Patent Application
20220235067
The present invention relates to organic device (e.g., solar cells and photodetectors) and methods of making the same.
(Note: This application references a number of different references as indicated throughout the specification by one or more reference numbers in superscripts, e.g., [x]. A list of these different publications ordered according to these reference numbers can be found below in the section entitled “References.” Each of these publications is incorporated by reference herein.
Organic optoelectronic devices have attracted attention for their inherent characteristics to be printed into ultra-thin, flexible, and conformal products through low-cost solution-processing techniques.[1,2] Organic semiconductors offer clear advantages related to their molecular diversities of organic chromophores which allow organic photodiodes to be explored for a wide range of optical applications by tailoring the absorption spectra.[3-7] Near-infrared (NIR) responsive organic semiconductors provide the potential in future applications such as semitransparent devices for building-integrated or green house systems.[8-10] Photodetectors (OPDs) with NIR responsivity have plenty of applications such as image sensing, night surveillance, optical communication, and health monitoring.[11-13]. NIR sensing has been conventionally realized with detectors based on single crystal inorganic semiconductor materials (e.g. Si, Ge, GaInAs, perovskite), which typically have drawbacks including costly processing, mechanical inflexibility, and sensitivity to temperature[37-39]. Considering that the spectral response window of organic semiconductors can be readily tuned by rational molecular design, NIR OPDs have been emerged as a cost-effective material choice. Bulk-heterojunction (BHJ) structure consisting of a donor and an acceptor components to promote the charge separation are generally adopted in organic solar cells.[14-16]
Conversely, the vast majority of state-of-the-art OPD systems comprise a semiconducting donor polymer governing the absorption range of the device, combined with a fullerene.[13] These OPDs exhibit disadvantages over commercially available inorganic devices (e.g. their relatively low photoresponsivities in the NIR region), which can be attributed to the low external quantum efficiency (EQE) due to limited NIR light absorption of the fullerene based acceptors, poor carrier generation and extraction with increased charge recombination when the bandgap of the donor polymers become narrower, large noise current and consequently low detectivity related to the poorly suppressed charge transport in the dark under reverse bias. Narrow bandgap (NBG) non-fullerene electron acceptors (NFA) are an emerging class of NIR organic absorbers that overcome some shortages of the BHJ photodiodes based on the fullerenes. Of note are the structural flexibility that provides an opportunity to promote an energy level variability as well as to tailor absorption characteristics toward NIR light with outstanding optoelectronic responses.[17-19] By combining narrow bandgap non-fullerene acceptors with wide gap donor polymers, strong absorption and high EQE across visible to NIR spectrum had led to solar cell efficiency up to 17%[40-41].
What is needed is organic devices with both improved efficiency at near infrared wavelengths and high transparency at visible wavelengths to realize efficient semitransparent and transparent NIR organic photodetectors and solar cells. The present disclosure satisfies this need.
The present disclosure describes a surprising and unexpected combination of donors and Non-Fullerene Acceptors (NFAs) which have strong absorption in the near infrared NIR region but relatively small absorption (high transparency) in the visible light region. In one or more examples, the donors and NFAs have narrow bandgaps of less than 1.4 eV (e.g., in the range 1.1-1.4 eV) while absorbing wavelengths up to at least ˜1100 nm. Compositions with such donor and non-fullerene acceptors exhibit broader NIR absorption and high transparency at visible wavelengths detected by human eyesight, thereby opening up new applications for semitransparent and transparent organic electronic devices.
In a first example, a NIR polymer PM2 and small molecule X2 were selected as the donors, and various NIR NFAs were selected as the acceptors for the electronic devices. Surprisingly, solar cells with PCE (power conversion efficiency) over 9% and photo current over 15 mA/cm2 were achieved. Surprisingly, photodetectors with responsivity as high as 0.36 A/W and specific detectivity close to 1012 Jones in the near IR region (beyond 800 nm wavelength) were also achieved. Surprisingly, the devices also showed very high transparency in the visible light region.
In a second example, NIR absorbing donor (P2) and various NIR-non fullerene acceptors were synthesized and introduced for semitransparent organic solar cells and organic photodetectors. The P2 polymer has an ultra-narrow energy bandgap of ˜1.12 V and absorbs sunlight at wavelengths of up to ˜1200 nm. Compositions with such NIR non-fullerene acceptors also exhibited broader NIR light absorption and high transparency for wavelengths detectable by a human's naked eye. As a result, solar cells with PCE (power conversion efficiency) close to 3% and photo current over 10 mA/cm2 were achieved. In one or more examples, the devices could surprisingly be fabricated without time consuming post-treatment.
Compositions of matter and devices according to embodiments described herein include, but are not limited to, the following.
1. A composition of matter, comprising:
a semiconducting compound of the structure (and isomers thereof):
wherein:
each Ar2 is independently a substituted or non-substituted aromatic functional group, or Ar2 is nothing and the valence of the ring is completed with hydrogen;
each Q is independently O, S Se, or N—R4;
each R and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain;
T is N, C—F, or C—Cl;
X is C, Si, Ge, N or P; and
a non-fullerene acceptor combined with the semiconducting compound.
2. The composition of matter of example 1, wherein the semiconducting compound comprises the structure:
3. The composition of matter of example 2, wherein the semiconducting compound comprises the structure:
4. The composition of matter of example 1, wherein the semiconducting compound comprises the structure:
wherein:
each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain;
T is N, C—F, or C—Cl; and
X is C, Si, Ge, N or P.
5. The composition of matter of example 1, wherein the semiconducting compound further comprises the structure:
wherein:
each Ar1 is independently a substituted or non-substituted aromatic functional group, or each Ar1 is nothing and the valence of the ring is completed with hydrogen.
each Z is independently O, S, Se, or N—R4;
each R1, R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
each Q is independently O, S Se, or N—R4;
6. The composition of matter of example 5, wherein the semiconducting compound comprises the structure:
7. The composition of matter of example 6, wherein the semiconducting compound comprises the structure:
8. The composition of matter of any of the examples 1-7, wherein the non-fullerene acceptor has the structure:
wherein:
each Ar is independently a substituted or non-substituted aromatic functional group, or each Ar is independently nothing and the valence of its respective thiophene ring is completed with hydrogen;
X is C, Si, Ge, N or P; Y is O, S, Se or N—R3;
Z is O, S, Se, or N—R3;
A is an acceptor moiety; and
each R1, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain; R4 is either a hydrogen or the same as Z—R2.
9. The composition of matter of any of the examples 1-8, wherein the non-fullerene acceptor has a bandgap less than or equal to the bandgap of the semiconducting compound.
10. The composition of matter of any of the examples 1-9, wherein the semiconducting compound comprises a semiconducting polymer having a repeat unit comprising the structure of any of the examples 1-7.
11. The composition of matter of example 10, wherein the semiconducting polymer comprises a semiconducting polymer having the structure:
12. The composition of matter of examples 10 or 11, wherein the acceptor unit in the semiconducting compound is regioregularly arranged along the conjugated main chain section (the side chains comprising C and H, e.g., C10H21 can be any R comprising a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
13. The composition of matter of any of the examples 1-12, wherein the non-fullerene acceptor comprises:
wherein R is a solubilizing chain comprising a substituted or non-substituted alkyl, aryl or alkoxy chain and the side chains comprising C and H may be any solubilizing chain comprising a substituted or non-substituted alkyl, aryl or alkoxy chain.
14. The composition of matter of any of the examples 1-13, wherein the non-fullerene acceptor has the structure:
wherein n is an integer; X is C, Si, Ge, N; EWG=any electron withdrawing group; and each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain.
15. The composition of matter of any of the examples 1-14, wherein the semiconducting compound comprises a semiconducting small molecule having a repeat unit comprising the structure of any of the examples 1-7.
16. The composition of matter of example 15, wherein the semiconducting compound is a small molecule donor comprising the structure of E-A-(D1-A)n-E, wherein:
D1 is
A is
each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain;
X is C, Si, Ge, N or P;
each T is independently C—H, N, C—F or C—Cl;
Q is O, S, Se or N—R4,
E is an alkylated bithiophene, and
n=1, 2 or 3.
16a. The composition of matter of any of the examples 1-6, wherein the semiconducting compound has a bandgap less than or equal to the bandgap of the non-fullerene acceptor.
17. The composition of matter of any of the examples 1-16, further comprising a bulk heterojunction comprising the composition of matter, wherein the semiconducting compound comprises a donor forming an interconnected network and heterointerface with the non fullerene acceptor, the donor and the acceptor are phase separated, and the donor phase is optionally crystalline.
18. The composition of matter of any of the examples 1-17, wherein the non fullerene acceptor has a bandgap of 1.3 eV or less (e.g., in a range of 0.8 eV-1.3 eV or in a range of 1 eV-1.3 eV where eV is electron volts.
19. A device comprising the composition of matter of any of the examples 1-18, wherein the device comprises a solar cell.
20. A device comprising the composition of matter of any of the examples 1-19, wherein the device comprises a photodetector.
21. The device of any of the examples 19-20, further comprising an active region comprising the composition of matter of any of the examples 1-18, wherein holes and electrons are generated in the active region in response to electromagnetic radiation incident on the active region,
the electrons are collected in the non-fullerene acceptor and are transmitted through to a cathode,
the holes are collected in the semiconducting compound comprising a donor and transmitted through to an anode,
so that the device outputs current in response to the electromagnetic radiation.
22. The device of any of the examples 19-21, comprising:
a film comprising a thickness of less than 1 micrometer and comprising:
23. The device of example 22, wherein the composition of matter has the structure:
each Ar1 and Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar1 and Ar2 is nothing and the valence of the ring is completed with hydrogen.
each Z is independently O, S, Se, or N—R4;
each X is C, Si, Ge, N or P;
each Q is independently O, S Se, or N—R4.
and
each R, R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
24. The device of example 23, wherein the semiconducting compound has the structure:
where each R, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain, and
n is an integer.
25. The device of example 22, further comprising:
a source of the visible electromagnetic radiation;
the photodetector on the source; and
a cover or window on the photodetector, such that the visible electromagnetic radiation is transmitted through the photodetector and the cover or window to a viewer.
26. The device of any of the examples 20-25, further comprising a biomedical sensor, wherein the photodetector measures electromagnetic radiation scattered or reflected from living tissue or cells.
27. A device, comprising:
an active region comprising organic semiconducting compounds (e.g., of any of the examples 1-18) outputting an electrical signal in response to electromagnetic radiation incident on the active region, the active region having:
a thickness less than 1 micrometer;
a transmittivity of at least 70% for the electromagnetic radiation having the wavelength in a range of 400 nanometers (nm) to 600 nm, and
an EQE of at least 30% for the electromagnetic radiation having the wavelength in a range of 700 nm-900 nm.
28. The device of example 27, wherein the semiconducting compound has the structure:
each Ar1 and Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar1 and Ar2 is nothing and the valence of the ring is completed with hydrogen.
each Z is independently O, S, Se, or N—R4;
each X is C, Si, Ge, N or P;
each Q is independently O, S Se, or N—R4
and
each R, R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
29. An infrared photodetector, comprising:
a first electrode;
a first carrier transport layer;
an active layer, wherein the first carrier transport layer is between the first electrode and the active layer;
a second carrier transport layer, wherein the active layer is between the first carrier transport layer and the second carrier transport layer; and
a second electrode on the second carrier transport layer, wherein:
the active layer comprises the composition of matter of any of the examples 1-18, and
a transmittance of the photodetector is 50% or more at the wavelengths of 400-600 nm.
30. The photodetector of example 29, wherein the semiconducting compound in the active layer comprises P2.
31. The photodetector of example 29, wherein the semiconducting compound in the active layer comprises PM2.
32. A device comprising the photodetector of any of the examples 29-31, comprising:
a display emitting the wavelengths;
the photodetector on or above the display;
a screen on or above the photodetector, wherein the display is readable by eye of a viewer through the photodetector; and
a circuit connected to the photodetector, the circuit determining a gesture of the viewer from a signal outputted from photodetector in response to infrared radiation incident on the photodetector.
33. The device of example 32, wherein the photodetector has a thickness of 3 micrometers or less.
Referring now to the drawings in which like reference numbers represent corresponding parts throughout:
In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
Small molecule organic solar cells exhibit many advantageous properties including, but not limited to, the possibility of tailoring their orbitals and molecular structure to achieve strong absorption, good reproducibility of synthesis, and high crystallinity for efficient charge transport.
Small molecule (SM) donor X2 and polymer donor PM2 are narrow band gap donors with optical bandgap (Egopt) of 1.41 eV and 1.42 eV respectively[14-19] and exhibiting absorption up to ˜ 900 nm in near IR region. The optimum BHJ morphology of OSCs (organic solar cells) requires nanoscale intermixed domains of donor and acceptor components with a bicontinuous network for efficient exciton splitting and charge transport[20]. Solution-processed polymer solar cells have been well established in the past decade[21]. However, in comparison with polymer-based OSCs, the morphological properties and the consequent photovoltaic properties of SM-OSCs are more sensitive to the conditions during film-forming process[22]. Crystallization of molecular donors is often crucial to ensure intermolecular interaction and phase separation required for the efficient photocurrent generation.[5-7,22] Thus, additional processing methods, i.e. solvent additives, thermal annealing (TA), and/or solvent vapor annealing (SVA) are required to kinetically favored crystallization and phase separation[23-26]. On the other hand, donor materials, such as X2, with a strong ability to crystallize without requiring additional treatments can produce favorable inter-connected networks and phase separation from the blends with fullerene.[27] Such compositions with non-fullerene small molecules as acceptor may yield highly efficient NIR organic solar cells via continuous, high throughput, and environmentally friendly manufacturing routes.
A1. Optical and Electrical Property of NIR Materials According to the First Example
The present disclosure describes electrical property and absorption spectra of multiple NIR non-fullerene acceptors (NFAs) and NIR donors. The molecular structures of donor and acceptors, named X2, PM2, ITIC-4F, IOTIC-4F and SiOTIC-4F, are illustrated in
The HOMO energy level and LUMO energy level of X2 are −5.04 eV and −3.63 eV, respectively. While PM2 has −5.30 eV for HOMO energy level and −3.88 eV for LUMO energy level. As shown in
ITIC-4F exhibits an optical bandgap of 1.51 eV and −5.58 eV HOMO and −4.19 eV LUMO. First ITIC-4F, IOTIC-4F and SiOTIC-4F were tested as the non-fullerene acceptors. The ITIC-4F Film exhibits broad absorption with a λmax of 717 nm and an Egopt of 1.51 eV. The IOTIC-4F film shows a maximum absorption peak at 856 nm with an absorption onset of ˜995 nm, corresponding to an Egopt of 1.25 eV. Lastly, structured SiOTIC-4F displays an absorption up to at least 1050 nm (Egopt of 1.18 eV) with a maxima peak at 937 nm, which is more redshifted relative to the other two acceptors. The main absorption region of these non-fullerene acceptors was in the wavelength range 700-1000 nm, which is desirable for semitransparent organic photovoltaic (OPV) and photodetector applications. The absorption in the visible light region is much weaker, up to ten times lower (X2 and PM2) than their maximum absorption, or close to zero (IOTIC-4F and SiOTIC-4F), which indicate high device transparency (low optical absorption) in visible light region.
aOptical band gap calculated from the absorption edge of thin film.
bHOMO enemy level estimated from the onset oxidation potential.
cLUMO energy level estimated from the onset reduction potential.
dLUMO energy level estimated from following equation ELUMO = Egopt + EHOMO.
A2. Photovoltaic Performance of Bulk-Heterojunction Solar Cells Comprising Active Regions Including Compositions of Matter According to the First Example
2.1. Device Fabrication and Characterization Method
Organic Photovoltaic (OPV) cells are one example of devices that can be used to clarify the sensitiveness of materials' response to photons. A composition comprising of NIR absorbing donor and non-fullerene-based acceptor (NFA) were prepared and tested in an OPV device having a high performance in the near infrared (NIR) region.
The OSC devices based on blends of X2:ITIC-4F and PM2:SiOTIC-4F were fabricated in an inverted device structure of indium-tin-oxide (ITO)/zinc oxide (ZnO)/NIR D:A/MoO3/Ag. For the OSCs of PM2:IOTIC-4F, the devices had configuration of indium-tin-oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/PM2:IOTIC-4F/ZnO nanoparticles (NPs)/Al. The procedures of device fabrication were as follows. Firstly, the ITO-coated glass substrates were cleaned with detergent, then ultra-sonicated in acetone and isopropyl alcohol, and subsequently dried in an oven at 100° C. Then, the cleaned ITO substrates were ultraviolet-ozone treated for 20 min to remove tiny organic residues. The zinc oxide (ZnO) solution was prepared using mixture of diethyl zinc solution in toluene and tetrahydrofuran (THF) (1:2, v/v %) and the ZnO film (ca. 35 nm thick) was spin-coated at 4000 rpm for 15 s and annealed at 110° C. for 15 min. PEDOT:PSS (Baytron P Clevios™ AI 4083, Germany) was spin-coated (ca. 45 nm thick), dried at 140° C. for 10 min. The X2:ITIC-4F blend solution was prepared by dissolving total 17 mg/ml of X2 (1.0 wt %) and ITIC-4F (1.5 wt %) in Chloroform (CF) with and without 0.5 vol % 1,8-diiodooctane or 0.5 vol % 1-chloronaphthalene. The blend solution of PM2:IOTIC-4F as well as the blend solution of PM2:SiOTIC-4F were prepared by dissolving total 20 mg/ml of PM2 (1.0 wt %):IOTIC-4F (1.0 wt %) in chlorobenzene (CB) or total 17 mg/ml of PM2 (1.0 wt %):SiOTIC-4F (1.5 wt %) in CF. These solutions were spin-coated at 2000 to 4000 rpm for film thickness optimization in a nitrogen-filled glove box. In case of conventional device of PM2:IOTIC-4F blend, the ZnO NPs in methanol were deposited on the active layer at 4000 rpm for 20 s. The device was pumped down in vacuum (<10−6 torr), and MoO3/Ag (6 nm/100 nm thick) electrode for inverted architecture or A1 (100 nm) electrode for conventional architecture were deposited by thermal evaporation. The active area via using aperture was 9.4 mm2. Photovoltaic characteristic measurement was carried out in the glove box using a solar simulator equipped with a Keithley 2635A source measurement unit. J-V curves were measured under AM 1.5G illumination at 100 mW cm2. EQE measurement was conducted in nitrogen-filled glove box using an EQE system. The monochromatic light intensity was calibrated using a Si photodiode and chopped at 100 Hz.
A2.2. Photovoltaic Characteristics
The blend of X2 small molecule donor and ITIC-4F non-fullerene acceptor has large HOMO/HOMO offset (˜0.54 eV), an efficient energetic driving force for exciton dissociation. The blends of PM2:SiOTIC-4F and PM2:IOTIC-4F showed much smaller HOMO/HOMO offset of −0.02 eV and 0.14 eV, respectively. Although PM2:SiOTIC-4F has negative value of HOMOoffset, it still exhibited decent photovoltaic performance. An empirical 0.3 eV minimum of HOMO/HOMO offset and LUMO/LUMO offset was observed in fullerene-based OSCs for efficient charge carrier generation, separation and extraction. It becomes problematic to maintain such energetic offset when the donor bandgap becomes narrower and narrower into the NIR region. As a consequence, poor carrier generation, extraction, and severe charge recombination is generally observed for NIR donor/fullerene based devices, especially when the bandgap approaches or is narrower than 1.4 eV, which leads to poor device EQE. It is encouraging that driving energies required for efficient charge separation in NIR donor/NFA solar cells described here are smaller than the empirical 0.3 eV observed in fullerene-based OSCs, which is advantageous to minimize energy losses from the difference between optical bandgap, this enables high photocurrents and high voltage to be achieved simultaneously.
These three compositions have sufficient absorption located in the near infrared region up to 1000 nm of wavelength, while simultaneously maintaining high transparency in visible region (400-600 nm), which is suitable for transparent organic photovoltaics. To optimize morphology of the active layers, device fabrication conditions were adjusted by introducing processing additive and changing spin-coating speed for thickness control.
In Current-voltage (J-V) characteristics, the X2:ITIC-4F-based devices exhibited a power conversion efficiency (PCE) of ˜1.43% with JSC of 5.36 mA cm−2, VOC of 0.69 V and fill factor (FF) of 0.39, which was fabricated with 0.5 vol % DIO additive. Note that X2 and ITIC-4F displayed overlapping absorption in the range of 600-800 nm wavelength, which could be a major factor of the limited JSC. PM2:IOTIC-4F showed higher PCE up to 5.25% arising from enhanced JSC of 11.59 mA cm−2 by 1 vol % CN additive in solution, VOC of 0.77 V and FF of 0.59. PM2:SiOTIC-4F based OPVs with a HOMOoffset close to 0 showed 3.17% PCE with 8.71 mA cm−2 (JSC), 0.66 V (VOC) and 0.55 (FF).
aX2:ITIC-4F = 1:1.5 (w/w), PM2:IOTIC-4F = 1:1 (w/w) and PM2:SiOTIC-4F = 1:1.5 (w/w)
bDiiodooctane (DIO), chloronaphthalene (CN) were used as processing solvent,
cHighest PCEs.
A.2.3 Electronic Proprieties
The indacenodithiophene (IDT)-based acceptors like ITIC-4F show lower electron mobility (10−5-10−4 cm2 V−1 s−1) as compared with the fullerene acceptors ((10−4-10−3 cm2 V−1 s−1), which may result in an unbalanced electron and hole mobility when blending with high hole mobility donor materials.
A3.1 Effects of Processing Environment
Small molecules may be sensitive to processing environment. Certain treatments such as thermal annealing, solvent annealing and adding processing additives were needed to form moderate crystallinities and adjust domain size. Too high crystallinity and large domain size reduces the charge dissociation efficiency and photovoltaic performance in the bulk heterojunction organic solar cells (OSCs).
The performance of OPVs based on X2:ITIC-4F with various treatments is shown below (see Table 3) Solvent vapor annealing with tetrahydrofuran (THF) gave higher PCE 2%, arising from improved JSC of 7.29 mA/cm2, VOC of 0.63, and FF of 0.45.
A.3.2 Bi Layer Structure Photovoltaic Performance
To confirm which materials are dominantly affected by additional treatment, bi-layer structured OPVs were fabricated and tested. We tested the effect of adding DIO processing additive, and THF-based solvent vapor annealing (SVA) for both donor layer and electron layer, respectively. Taking into account of material solubility and device configuration, the OPVs were fabricated with conventional structure (ITO/MoO3/Donor/Acceptor/Al). the OPV performance is listed in Table 4. For the best result, X2 required DIO processing additive and solvent vapor annealing, while, ITIC-4F needed only solvent vapor annealing. This indicates that X2 needs molecular re-ordering in the film for carrier balance with electron movement in ITIC-4F domains.
A.4 Device Performance with Donor PM2 as Function of NFA
Photovoltaic properties of PM2 with various NFAs with bandgap in the range of 1.1-1.4 eV were tested either in a device or an inverted device structure. The NFA bandgaps, HOMO-LUMO levels, device Voc, Jsc, FFs, PCEs, EQE peaks and EQE edges are summarized in tabular form in
A.5 Photodetector Performance of Bulk-Heterojunction Devices
Taking advantage of the optoelectronic properties of PM2:NFA and X2:NFA, we also fabricated efficient NIR organic photodetectors. The responsivity (R), which is an important parameter for evaluating the light-responding performance of a photodetector, is defined as the ratio of photocurrent to the incident light intensity, and can be calculated from the EQE according to the following equation:
where Jph is the photocurrent density in A/cm2, Ilight is the incident light intensity in W/cm2, λ is the wavelength.
In addition to responsivity, another critical figure of merit for the photodetector is specific detectivity (D*), which evaluates the sensitivity of a photodetector to weak optical signals. The shot noise-limited specific detectivity can be calculated from the responsivity and dark J-V characteristics. The D* of the photodetectors is shown in
Since the active layer absorption in fullerene based solar cells is mainly in the range from 300 nm to 800 nm, utilization of the near infrared (NIR) region of the solar spectrum has been limited.[5-8] Till now semitransparent organic solar cells have limited usage as an energy source for Internet of Things (IoT) generation and applications such as vehicle windows and smart building exteriors or windows. Moreover, since 50% of the sunlight at the earth's surface comprises infrared (IR) radiation intensity, ideal organic solar cells as next generation energy sources require narrow bandgap materials.
The combination of NIR donor and NIR NFAs described herein may be used realize high performance solar cells with high transparency. As described herein, by tuning their optical and electrical properties, donors and acceptors can absorb in the near infrared (NIR) region of the electromagnetic spectrum. In this regard, P2 was chosen as a narrow band gap material (bandgap less than 1.12 eV; HOMO energy level and LUMO energy level of P2 are −5.16 eV and −3.70 eV) to combine with NIR non-fullerene acceptors exhibiting a narrow bandgap of less than 1.30 eV. Such compositions of P2:COTIC-2F, P2:CO6IC, P2:C2P1, P2:GeOTIC-4F-EH and P2:GeOTIC-4F-BO can be applied to NIR organic solar cells and photodetectors. These narrow band gap devices are shown here to exhibit relatively higher transparency in the visible region as compared to fullerene-based organic solar cells[2-4] while also exhibiting strong absorption of photons in the NIR region.
In a recent study, it was shown that crystallization of molecular materials is often crucial for ensuring intermolecular interactions and phase separation required for the efficient electron extraction. Thus, additional processing methods, i.e. solvent additives, thermal annealing (TA) are required to kinetically favor crystallization and phase separation[14-17].
B1. Optical and Electrical Property of NIR Materials According to the Second Example
This example describes electrical property and absorption spectra of donor P2 and acceptors (COTIC-2F, CO6IC, C2P1, GeOTIC-4F-EH and GeOTIC-4F-BO). The chemical structures are illustrated in
The COTIC-2F acceptor exhibits broadened absorption with a λmax of 960 nm and an Egopt of 1.29 eV in solution. The COTIC-2F film shows a maximum absorption peak at 982 nm with an absorption onset of ˜1160 nm (Egopt ˜1.07 eV). The CO6IC acceptor exhibits broadened absorption with a λmax of 760 nm and an Egopt of 1.50 eV in solution. The C2P1 solution shows a maximum absorption peak at 755 nm and 833 nm with an absorption onset of ˜968 nm, corresponding to an Egopt of 1.28 eV. Lastly, structured GeOTIC-4F series materials display absorption until 1060 nm in solution (Egopt of 1.14 and 1.17 eV, respectively) with a maxima peak at 940 nm. The main absorption region of these non-fullerene acceptors is at 700-1000 nm with weak or close to zero absorption in the visible light range, which is desirable for semitransparent and transparent organic photovoltaic (OPV) and photodetector applications.
aOptical band gap calculated from the absorption edge of solution (materials are dissolved in chloroform (CF)).
bHOMO energy level estimated from the onset oxidation potential.
cLUMO energy level estimated from the onset reduction potential.
B2. Device Fabrication and Characterization Method
The OSC devices based on blends of P2:COTIC-2F, P2:CO6IC, P2:C2P1, P2:GeOTIC-4F-EH and P2:GeOTIC-4F-BO were fabricated in an inverted device structure of indium-tin-oxide (ITO)/zinc oxide (ZnO)/NIR D:A/MoO3/Ag or conventional device structure of ITO/PEDOT:PSS/NIR D:A/Al. This device architecture (illustrated in
Photovoltaic properties of P2 with various NFAs with bandgap in the range of 1.0-1.3 eV were tested either in a conventional or an inverted device structure. The NFA bandgaps, HOMO-LUMO levels, device Voc, Jsc, FFs, PCEs, EQE peaks and EQE edges are summarized in tabular form in
As described herein, related non-fullerene acceptor materials can be designed and synthesized with different chemical structures to tune chemical properties for narrower bandgaps and higher device efficiencies. Further examples of NFAs include those illustrated in
In addition, the device performance can be improved through further morphology control of active layer. Further device optimization includes but not limited to donor/acceptor ratio, solvent, solution concentration, processing additive type and amount, film deposition method (spin coating, blade coating, drop casting, spray coating, ink-jet printing etc.), film deposition temperature, film thickness, buffer layers (electron transporting layer, hole transporting layer).
The compositions of matter according to the embodiments described herein may be included in solar cell or photodetector devices having the structure illustrated in
The above systems can be applied to other organic electronic devices including organic field effect transistor and organic sensor. With a similar working principle to organic solar cells (OSCs), organic photodetectors (OPDs) with NIR responsivity have plenty of applications such as image sensing, night surveillance, optical communication, and health monitoring. Considering that the spectral response window of organic semiconductors can be readily tuned by rational molecular design, NIR OPDs have been emerged as a cost-effective material choice; typically, epitaxial grown inorganic materials such as InGaAs or quantum dots are cost intensive. Narrow bandgap (NBG) non-fullerene electron acceptors (NFA) are an emerging class of NIR organic absorbers that overcome the shortages of the BHJ photodiodes based on fullerenes. Of note are the structural flexibility that provides an opportunity to promote an energy level variability as well as to tailor absorption characteristics toward NIR light with outstanding optoelectronic responses such as efficient charge generation with low photon energy losses. In this context, the recent impressive improvement in device efficiency of OSC is expected to be of particular relevance with the advent of highly efficient NIR NFA materials. Conversely, the vast majority of state-of-the-art OPD systems comprise a narrow bandgap polymer governing the absorption range of the device, combined with a fullerene. These OPDs are expected to exhibit disadvantages over commercially available inorganic devices (e.g. their relatively low photo responsivities in the NIR region), which can be attributed to intrinsic properties of the fullerene acceptor.
As described herein, a bulk heterojunction comprising PM2, P2, X2 or its analogs and an acceptor (NFA) of maximum absorption wavelength in the NIR region generates photo-current under NIR light irradiation while transmitting most of light in the visible region. This unique feature allows us to fabricate semi-transparent NIR photodetectors. These photodetectors can be placed onto a display without greatly changing color tone and reducing brightness so that the display can recognize shape and motion of object in front of it. They can also be placed onto photodetectors detecting visible light without greatly reducing the responsivity of the photodetectors underneath so that the stack of photodetectors can detect visible and NIR separately at the same time. They can be useful not only for displays and image sensors but also for health monitoring systems including blood flow meters, hart rate monitors, and proprioception sensors, and metrology applications. Semi-transparent or transparent photodetectors can open up possibility for easier integration with other optical devices.
In one or more examples, the health system using NIR photodetectors according to embodiments described herein does not need a separate light source because the detector can sense ambient light, leading to a more compact health monitoring system.
E.1: Example Donors
Block 1800 represents providing one or more donors (e.g., electron donors).
In one or more examples of this invention, the semiconductor donor compound comprises a conjugated main chain section, the conjugated main chain section having a repeating donor unit (D1) comprises a dithiophene structure.
In one or more embodiments, the repeating donor unit of the semiconductor compound comprises the structure:
wherein each Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar2 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar2 groups can be the same. Each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. X is C, Si, Ge, N or P. In some embodiments, the R comprising the substituted or non-substituted alkyl, aryl, alkoxy or thioether chain can be a C6-C50 substituted or non-substituted chain, —(CH2CH2O)n (n=2˜20), C6H5, —CnF(2n+1) (n=2˜20), —(CH2)nN(CH3)3Br (n=2˜20), 2-ethylhexyl, PhCmH2m+1 (m=1-20), —(CH2)nN(C2H5)2 (n=2˜20), —(CH2)nSi(CmH2m+1)3 (m, n=1 to 20), or —(CH2)nSi(OSi(CmH2m+1)3)x(CpH2p+1)y (m, n, p=1 to 20, x+y=3).
In one or more embodiments, the donor unit comprises:
In one or more embodiments, the semiconductor donor compound is a polymer.
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section having a repeating acceptor unit (A) that comprises the structure:
wherein each Ar3 is independently a substituted or non-substituted aromatic functional group, or each Ar3 is nothing and the valence of the ring is completed with hydrogen. Each T is N, C—H, C—F or C—Cl.
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section having an acceptor unit (A) that comprises the structure:
wherein each T is C—H, N, C—F or C—Cl, and Q is O, S, Se or N—R4, Each R4 is independently hydrogen or a substituted or non-substituted alkyl or aryl chain.
In one or more embodiments, the acceptor unit comprises:
In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section.
In one or more embodiments, the semiconductor donor compound is a polymer.
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section further comprises a second donor unit (D2) that comprises the structure:
wherein each Ar1 is independently a substituted or non-substituted aromatic functional group, or each Ar1 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar1 groups can be the same. Each R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R1 groups can be the same. Each Z is independently O, S, Se, or N—R4. In some embodiments, the Z groups can be the same. The R1 and R4 comprising the substituted or non-substituted alkyl, aryl, alkoxy or thioether chain can be a C6-C50 substituted or non-substituted chain, —(CH2CH2O)n (n=2˜20), C6H5, —CnF(2n+1) (n=2˜20), —(CH2)nN(CH3)3Br (n=2˜20), 2-ethylhexyl, PhCmH2m+1 (m=1-20), —(CH2)nN(C2H5)2 (n=2˜20), —(CH2)nSi(CmH2m+1)3 (m, n=1 to 20), or —(CH2)nSi(OSi(CmH2m+1)3)x(CpH2p+1)y (m, n, p=1 to 20, x+y=3).
In one or more embodiments, the second donor unit comprises:
In one or more embodiments, the second donor unit comprises:
wherein each Ar1 is independently a substituted or non-substituted aromatic functional group, or each Ar1 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar1 groups can be the same. Each R2, R3 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R2 groups can be the same. In some embodiments, the R3 groups can be the same. Each Z and Z1 is independently O, S, Se, or N—R4. In some embodiments, the Z groups can be the same. In some embodiments, the Z1 groups can be the same.
In one or more embodiments, the second donor unit comprises:
In one or more embodiments, the second donor unit comprises:
In one or more embodiments, the second donor unit comprises:
In one or more embodiments, the second donor unit comprises:
In one or more embodiments, the semiconductor donor compound is a polymer.
In one or more embodiments, the semiconductor donor compound comprises a conjugated main chain section, the conjugated main chain section further comprises a second donor unit (D2) that comprises the structure:
wherein each Ar4 is independently a substituted or non-substituted aromatic functional group, or each Ar4 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar4 groups can be the same. Each Z is independently O, S, Se, or N—R4. Each R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
In one or more embodiments, the second donor unit comprises:
In one or more embodiments, the semiconductor compound is a polymer.
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section having a D1-A structure, while D1 is a first donor unit, A is an acceptor unit.
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section having a D1-A structure that comprises the structure:
wherein each Ar2 and Ar3 is independently a substituted or non-substituted aromatic functional group, or each Ar2 and Ar3 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar2 groups can be the same. In some embodiments, the Ar3 groups can be the same. Each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. X is C, Si, Ge, N or P. T is C—H, N, C—F or C—Cl.
In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section.
In one or more embodiments, the conjugated main chain section comprises:
wherein the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
wherein each Ar2 s independently a substituted or non-substituted aromatic functional group, or each Ar2 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar2 groups can be the same. Each R and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. X is C, Si, Ge, N or P. T is C—H, N, C—F or C—Cl. Q is O, S, Se or N—R4.
In one or more embodiments, the conjugated main chain section comprises:
wherein the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises;
Each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. X is C, Si, Ge, N or P. T is C—H, N, C—F or C—Cl.
In one or more embodiments, the conjugated main chain section comprises:
In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section.
In one or more embodiments, the conjugated main chain section comprises:
In one or more embodiments, the conjugated main chain section comprises:
In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section.
In one or more embodiments, the semiconductor compound is a semiconductor polymer.
In one or more embodiments, the semiconductor polymer comprises the structure:
wherein each Ar2 s independently a substituted or non-substituted aromatic functional group, or each Ar2 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar2 groups can be the same. Each R and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. X is C, Si, Ge, N or P. T is C—H, N, C—F or C—Cl. Q is O, S, Se or N—R4. n is an integer.
In one or more embodiments, the acceptor unit is regioregularly arranged along the semiconductor polymer backbone.
In one or more embodiments, the semiconductor polymer comprises the structure:
Wherein each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. X is C, Si, Ge, N or P. T is C—H, N, C—F or C—Cl.
In one or more embodiments, the acceptor unit is regioregularly arranged along the semiconductor polymer backbone.
In one or more embodiments, the semiconductor polymer comprises the structure:
In one or more embodiments, the acceptor unit is regioregularly arranged along the semiconductor polymer backbone.
In one or more embodiments, the semiconducting compound further comprising the structure:
wherein:
each Ar is independently a substituted or non-substituted aromatic functional group, or each Ar is nothing and the valence of the ring is completed with hydrogen. each Z is independently O, S, Se, or N—R4; each R1, R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. each Q is independently O, S Se, or N—R4; T is C—H, N, C—F, or C—Cl.
In one or more embodiments, the semiconducting compound further comprising the structure:
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section having a D1-A-D2-A structure, while D1 is a first donor unit, D2 is a second donor unit, A is an acceptor unit.
In one or more embodiments, the semiconductor compound comprises a conjugated main chain section, the conjugated main chain section having a D1-A-D2-A structure that comprises the structure:
wherein each Ar1 and Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar1 and Ar2 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar1 groups can be the same. In some embodiments, the Ar2 groups can be the same. Each R, R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. In some embodiments, the R1 groups can be the same. Each Z is independently O, S, Se, or N—R4. In some embodiments, the Z groups can be the same. X is C, Si, Ge, Nor P; T is C—H, N, C—F, or C—Cl, and Qis O, S, Se or N—R4. In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
wherein the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
wherein each Ar1 and Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar1 and Ar2 is nothing and the valence of the ring is completed with hydrogen. In some embodiments, the Ar1 groups can be the same. In some embodiments, the Ar2 groups can be the same. Each R, R2, R3 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. In some embodiments, the R2 groups can be the same. In some embodiments, the R3 groups can be the same. Each Z and Z1 is independently O, S, Se, or N—R4. In some embodiments, the Z groups can be the same. In some embodiments, the Z1 groups can be the same. X is C, Si, Ge, N or P, and Q is O, S, Se or N—R4. In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
In one or more embodiments, the conjugated main chain section comprises:
wherein each R, R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. In some embodiments, the R1 groups can be the same. Each Z is independently O, S, Se, or N—R4. In some embodiments, the Z groups can be the same. X is C, Si, Ge, N or P, and Q is O, S Se, or N—R4. In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
wherein the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
In one or more embodiments, the conjugated main chain section comprises:
wherein each R, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. In some embodiments, the R2 groups can be the same. In some embodiments, the R3 groups can be the same. X is C, Si, Ge, N or P In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises.
Wherein the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the conjugated main chain section comprises:
In one or more embodiments, the semiconductor compound is a semiconductor polymer.
In one or more embodiments, the semiconductor polymer comprises:
wherein each R and R1 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. In some embodiments, the R1 groups can be the same. X is carbon (C), silicon (Si), germanium (Ge), nitrogen (N) or phosphorus (P) In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the semiconductor polymer comprises:
wherein each R, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In some embodiments, the R groups can be the same. In some embodiments, the R2 groups can be the same. In some embodiments, the R3 groups can be the same. In one or more embodiments, the acceptor unit is regioregularly arranged along the conjugated main chain section as shown in the structure.
In one or more embodiments, the semiconductor polymer comprises:
In one or more embodiments, the semiconductor donor polymer comprises a conjugated main chain section, the conjugated main chain section having a repeating unit of D1-A-D2-A structure, while D1 is a first donor unit with strong electron donating capability, D2 is a second donor unit with weaker electron donating capability, A is a strong acceptor unit. Such backbone structures can tune the optical bandgap, HOMO-LUMO levels and yield well-ordered polymer crystallite phases in thin films.
In one or more embodiments, the small molecule donor comprises the structure of E-A-(D1-A)n-E, while D1 can be selected from any of the above listed first donor units, and A can be selected from any of the above listed acceptor units. n=1-10. E is a terminal end group which can be independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy group.
In one or more embodiment, the small molecule donor comprises the structure of E-A-(D1-A)n-E, while D1 is
wherein each R and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. X is C, Si, Ge, N or P. T is C—H, N, C—F or C—Cl, and Q is O, S, Se or N—R4, E is an alkylated bithiophene, n=1, 2, 3, 4 or 5. Each T can be the same or different. Each X can be the same or different.
In one or more embodiment, the small molecule donor comprises the structure:
wherein each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain. In one or more embodiments, R1 is 2-ethylhexyl, and R2 is hexyl. In another embodiment, R2 is 2-ethylhexyl, and R1 is hexyl.
The R, R1, R2, R3 and R4 groups can be a linear or branched side-chain comprising a C3-C50, C5-C50, C8-C50, or C9-C50 substituted or non-substituted alkyl chain. Examples of alkyl chains include isopropyl, sec-butyl, t-butyl, 1,2-dimethylpropyl, 1,1-dimethyl-propyl, 4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1,2,2-trimethylpropyl, 1,1,2-trimethylpropyl, 5-methylhexyl, 1-methylhexyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl, 1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, 6-methylheptyl, 1-methylheptyl, 1,1,3,3-tetramethylbutyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-methyloctyl, 1-, 2-, 3-, 4- or 5-ethylheptyl, 1-, 2- or 3-propylhexyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- and 8-methylnonyl, 1-, 2-, 3-, 4-, 5- or 6-ethyloctyl, 1-, 2-, 3- or 4-propylheptyl, dimethyloctyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-methyldecyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-ethylnonyl, 1-, 2-, 3-, 4- or 5-propyloctyl, 1-, 2- or 3-butylheptyl, 1-pentylhexyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-methylundecyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- or 8-ethyldecyl, 1-, 2-, 3-, 4-, 5- or 6-propylnonyl, 1-, 2-, 3- or 4-butyloctyl, 1-, 2-pentylheptyl, branched butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonoadecyl, eicosyl with one or more branch points at any carbon of the alkyl chain, such as 2 (or 1, or 3, or 4)-ethylhexyl, 2 (or 1, or 3, or 4)-hexyldecyl, 2 (or 1, or 3, or 4)-octyldodecyl, 2 (or 1 or 3, or 4)-butyloctyl, 4 (or 1, or 2, or 3, or 5, or 6)-butyldecyl, 5 (or 1, or 2, or 3, or 4, or 6, or 7)-butylundecyl, 6 (or 1, or 2, or 3, or 4, or 5, or 7, or 8)-butyldodecyl, 12 (or 1, or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 11, or 13, or 14)-butyloctadecyl, and the like.
E.2. Example Non-Fullerene Acceptors
Block 1802 represents combining the donor(s) with one or more non-fullerene acceptor (NFA), e.g., to form a blend of the one or more donors and the one or more NFAs.
In one or more embodiments, the non-fullerene acceptors in this invention comprise the general structure:
EWG=any electron withdrawing group, can be but not limited to F, Cl. Br, I, CN, CF3, NO2, sulfonate, ketone, ester, n=1, 2, 3 or 4. Examples of Ar can be but not limited to the following:
wherein X is C, Si, Ge, N or P; Each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain.
In one or more embodiments, the non-fullerene acceptors in this invention comprise the general structure:
EWG=any electron withdrawing group, can be but not limited to F, Cl. Br, I, CN, CF3, NO2, sulfonate, ketone, ester, n=1, 2, 3 or 4. Examples of Ar can be but not limited to the following:
wherein X is C, Si, Ge, N or P; Each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain.
In one or more embodiments, the non-fullerene acceptors in this invention comprise the general structure:
wherein each Ar is independently a substituted or non-substituted aromatic functional group, or each Ar is independently nothing and the valence of its respective thiophene ring is completed with hydrogen, each Ar may comprise one, two, three or more 5-membered or 6-membered aromatic rings; X is C, Si, Ge, N or P; Y is O, S, Se or N—R3; Z is oxygen (O), sulphur/sulfur (S), selenium (Se), or N—R3; Each R1, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain; R4 is either a hydrogen or the same as Z—R2. In some embodiments, the R1, R2 and R3 groups can be the same. The R1, R2 and R3 comprising the substituted or non-substituted alkyl, aryl or alkoxy chain can be a C6-C50 substituted or non-substituted alkyl or alkoxy chain, —(CH2CH2O)n (n=2˜30), C6H5, —CnF(2n+1) (n=2˜50), —(CH2)nN(CH3)3Br (n=2˜50), 2-ethylhexyl, PhCmH2m+1 (m=1-50), —(CH2)nN(C2H5)2 (n=2˜50), —(CH2)nSi(CmH2m+1)3 (m, n=1 to 50), or —(CH2)nSi(OSi(CmH2m+1)3)x(CpH2p+1)y (m, n, p=1 to 50, x+y=3). Examples of A are listed in FIGS. 22a-g of U.S. patent application Ser. No. 16/179,294.
The R1, R2, R3 and R4 groups can be a linear or branched side-chain comprising a C3-C50, C5-C50, C8-C50, or C9-C50 substituted or non-substituted alkyl chain. Examples of alkyl chains include isopropyl, sec-butyl, t-butyl, 1,2-dimethylpropyl, 1,1-dimethyl-propyl, 4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1,2,2-trimethylpropyl, 1,1,2-trimethylpropyl, 5-methylhexyl, 1-methylhexyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl, 1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, 6-methylheptyl, 1-methylheptyl, 1,1,3,3-tetramethylbutyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-methyloctyl, 1-, 2-, 3-, 4- or 5-ethylheptyl, 1-, 2- or 3-propylhexyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- and 8-methylnonyl, 1-, 2-, 3-, 4-, 5- or 6-ethyloctyl, 1-, 2-, 3- or 4-propylheptyl, dimethyloctyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-methyldecyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-ethylnonyl, 1-, 2-, 3-, 4- or 5-propyloctyl, 1-, 2- or 3-butylheptyl, 1-pentylhexyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-methylundecyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- or 8-ethyldecyl, 1-, 2-, 3-, 4-, 5- or 6-propylnonyl, 1-, 2-, 3- or 4-butyloctyl, 1-, 2-pentylheptyl, branched butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonoadecyl, eicosyl with one or more branch points at any carbon of the alkyl chain, such as 2 (or 1, or 3, or 4)-ethylhexyl, 2 (or 1, or 3, or 4)-hexyldecyl, 2 (or 1, or 3, or 4)-octyldodecyl, 2 (or 1 or 3, or 4)-butyloctyl, 4 (or 1, or 2, or 3, or 5, or 6)-butyldecyl, 5 (or 1, or 2, or 3, or 4, or 6, or 7)-butylundecyl, 6 (or 1, or 2, or 3, or 4, or 5, or 7, or 8)-butyldodecyl, 12 (or 1, or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 11, or 13, or 14)-butyloctadecyl, and the like.
In one or more embodiments, the non-fullerene acceptors in this invention comprise the general structure:
wherein X is C, Si, Ge, N or P; Y is O, S or Se; Z is O or S; Each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain. A is an acceptor moiety. Examples of A are listed in FIGS. 22a-g of U.S. patent application Ser. No. 16/179,294.
In one or more embodiments, the non-fullerene acceptors comprise the general structure:
wherein X is C, Si, Ge, N or P; Y is O, S or Se; Z is O or S; Each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain. A is an acceptor moiety. Examples of A are listed in FIGS. 22a-g of U.S. patent application Ser. No. 16/179,294.
In one or more embodiments, the non-fullerene acceptors in this invention comprise the general structure:
EWG=any electron withdrawing group, can be but not limited to F, Cl. Br, I, CN, CF3, NO2, sulfonate, ketone, ester, n=1, 2, 3 or 4. Examples of Ar can be but not limited to the following:
wherein X is C, Si, Ge; Each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain.
In one embodiment, the organic semiconducting molecule has the structure
wherein
R1 is 4-hexylphenyl, and
R2 is 2-ethylhexyl or R1 and R2 are each independently a solubilizing chain, hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
In one or more embodiments, the A-D′-D-D′-A semiconductors comprise the general structure:
wherein X s C, Si, Ge; EWG=any electron withdrawing group, can be but not limited to F, Cl. Br, I, CN, NO2, sulfonate, ketone, ester; n=1, 2, 3 or 4; Each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain.
In another embodiment, the NFA has the structure:
wherein
R1 is 4-hexylphenyl, and
R2 is 2-ethylhexyl, or R1 and R2 are each independently hydrogen, a solubilizing chain, or a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
Other examples include, but are not limited to.
wherein C8H17, 4-hexylphenyl, C6H13 and 2-ethylhexyl can be replaced with hydrogen, a solubilizing chain, or a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
In yet a further embodiment, the organic semiconducting molecule has the structure:
wherein
or R is a solubilizing chain or hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
In yet another embodiment, the NFA has the structure:
or wherein R is a solubilizing chain or hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
In yet further examples, the molecule or acceptor comprises
wherein 2-ethylhexyl, C2H5, C4H9 can be replaced with R that is a solubilizing chain or hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
Examples of dithiophene units include those illustrated in Table B (
Block 1804 represents the end result, a composition of matter comprising the NFA and the donor.
Block 1806 represents optionally processing the composition of matter in a device.
In one or more examples, the device or composition of matter comprises a plurality of the electron donors and a plurality of the organic semiconducting molecules that are phase separated, wherein the organic semiconducting molecules are disposed in a hierarchical network and the electron donors comprising the second organic semiconducting molecules occupy spaces in the hierarchical network. In one example, the hierarchical network comprises larger mid rib shaped regions connected by smaller or thinner regions. In one example, the composition of matter is solution processed with an additive that promotes formation of the hierarchical network.
In one or more embodiments, the semiconductor donor compound has a HOMO in a range of −4.8 eV to −5.5 eV, a LUMO in a range of −3.5 eV to −4.0 eV, and a bandgap in a range of 1.0 eV to 1.4 eV.
In one or more embodiments, the semiconductor donor compound has HOMO in a range of −5.0 eV to −5.3 eV, a LUMO in a range of −3.5 eV to −3.9 eV, and a bandgap in a range of 1.0 eV to 1.3 eV.
In one or more embodiments, the semiconductor donor compound has a bandgap narrower than 1.3 eV.
In one or more embodiments, the semiconductor donor compound has a bandgap narrower than 1.2 eV or narrower than 1.1 eV.
In one or more embodiments, the semiconductor donor compound has a main absorption band between 600 and 1200 nm.
In one or more embodiments, the semiconductor donor compound has a main absorption band between 600 and 900 nm.
In one or more embodiments, the semiconductor donor compound has a main absorption band between 700 and 1100 nm.
In one or more embodiments, the semiconductor donor compound has a maximum extinction coefficient in solution of at least 1×10 M−1 cm−1.
In one or more embodiments, the NFA has a HOMO in a range of −5.0 eV to −5.5 eV, a LUMO in a range of −3.8 eV to −4.3 eV, and a bandgap in a range of 1.0 eV to 1.4 eV.
In one or more embodiments, the NFA has a bandgap narrower than 1.3 eV.
In one or more embodiments, the NFA has a bandgap narrower than 1.2 eV or narrower than 1.1 eV.
In one or more embodiments, the NFA has a main absorption band between 850 and 1100 nm.
In one or more embodiments, the NFA has a maximum extinction coefficient in solution of at least 1×105 M−1 cm−1.
In one or more embodiments, the device:
In one or more embodiments, the active region (e.g., in the solar cell or the photodetector) is sensitive to infrared wavelengths (i.e., the bandgap of the acceptor molecule and/or donor molecule are sufficiently low to absorb infrared radiation).
The photovoltaic device may have a standard or inverted structure. It may comprise a substrate, a first electrode deposited on the substrate, a second electrode, an electron conducting/hole blocking layer deposited either between the first electrode and the active layer, or between the active layer and the second electrode, and an optional hole conducting/electron blocking layer deposited either in between the first electrode and the active layer, or between the active layer and the second electrode.
In one or more examples, the device 1400, as illustrated in
holes and electrons are generated in the active region in response to electromagnetic radiation incident on the active region,
the electrons are collected in the electron acceptor and are transmitted through to the cathode, and
the holes are collected in the electron donor and transmitted through to the anode.
Also illustrated is a hole blocking layer 1408 between the cathode and the active region, and an electron blocking layer 1410 between the anode and the active region.
During operation, either or both the electron donor and the electron acceptor absorb photons to create electron-hole pairs, the electron acceptor (interfacing with the electron donor) receives or collects the electron in the electron hole pair and transports the electron to the cathode interface layer/hole blocking layer and the cathode. The hole is transported by the electron donor to the anode interface layer/electron blocking layer and then the anode.
In one or more examples, the device 1400 comprises an infrared photodetector, comprises a first electrode 1402 (e.g., anode or cathode); a first carrier transport layer 1408; an active layer 1406, wherein the first carrier transport layer (e.g., hole blocking layer or electron blocking layer) is between the first electrode and the active layer; a second carrier transport layer 1410, wherein the active layer is between the first carrier transport layer and the second carrier transport layer; and a second electrode 1404 (e.g., anode or cathode) on the second carrier transport layer (e.g., hole blocking layer or electron blocking layer). The active layer comprises the composition of matter of Block 1804 and a transmittance of the photodetector is 50% or more at the wavelengths of 400-600 nm. In one or more embodiments, transmittance of the active layer is 70% or more (e.g., in a range of 70%-90%, 70%-99%, 70%-100%). In one or more examples, transmittance of the photodetector of 50% or more (e.g., in a range of 50%-90%, 50%-99%, 50%-100%) in the wavelengths of 400-600 nm means that the mean transmittance for the wavelengths (in the range of 400-600 nm) is 50% or more. The transmittance of the photodetector can be measured, if the photodetector is stacked on a transparent matter such as window, by differentiating the transmittance of the stack of the transparent matter and the photodetector and that of the transparent matter without the photodetector.
In one or more examples (referring also to
In one or more examples (referring also to
In one or more examples, the thickness 1450 of photodetector is preferably less than 3 micrometers.
Examples of a substrate include, but are not limited to, a flexible substrate, a plastic substrate, a polymer substrate, a metal substrate, a silicon substrate, or a glass substrate. In one or more embodiments, the flexible substrate is at least one film or foil selected from a polyimide film, a polyether ether ketone (PEEK) film, a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a polytetrafluoroethylene (PTFE) film, a polyester film, a metal foil, a flexible glass film, and a hybrid glass film. Examples of cathode interface layer include, but are not limited to ZnO and/or ITO. The ZnO can include multiple layers (e.g., two layers) and have a surface roughness of less than 5 nm over an area of 0.2 cm2.
Examples of anode interface layer include, but are not limited to MoOx having a thickness in a range of 5-150 nm. Further examples include, but are not limited to, the hole transporting/conducting layer material selected from, but not limited to, the group comprising or consisting of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS), p-type organic small molecule semiconductors such as Spiro-MeOTAD, pentacene, biscarbazolylbenzene, oligomer semiconductors, polymer semiconductors such as PTAA, poly(3-hexylthiophene-2,5-diyl) (P3HT), donor-acceptor copolymer semiconductors such as PCPDTBT, PCDTBT, metal oxides such as Cul, CuBr, CuSCN, Cu2O, CuO or CIS. VOx, NbOx, MoOx, WOx, NiOx, where x is 3 or less than 3, or other main group or transition metal oxides and a compound as shown in FIG. 1 of U.S. Ser. No. 14/954,131.
Examples of cathode material include, but are not limited to, ITO. In further examples, the electron transporting/conducting layer material is selected from, but not limited to, the group comprising or consisting of TiO2, ZnO, SnO, SnO2, SiO2, CeO2, ZrO2, CdSe, WO3, ZnSnO4, PbI2, SrTiO3, fullerene based electron acceptors (C60, C70, PC61BM, PC71BM, ICBA), borane based electron acceptors (3TPYMB), Bathocuproine (BCP), bathophenanthroline (Bphen), ITIC type of non-fullerene acceptors, NDI and PDI based non-fullerene acceptors, and the combination of above (double layer). The electron transporting layer may have a thickness of 2 nm to 500 nm, preferably a thickness of 20 nm to 200 nm, more preferably a thickness of 20-50 nm, or 50 nm to 100 nm.
Examples of cathode and anode materials include, but are not limited to, a metal or at least one material selected from gold, aluminum, copper, silver, silver paste, palladium, platinum, nickel, a combination/bilayer of metal and molybdenum oxide or molybdenum (wherein the MoOx is an interlayer), a liquid metal (e.g., mercury alloy, eutectic gallium indium), a transparent conductive layer, carbon nanotubes, graphene, carbon paste, PEDOT:PSS, and a conjugated polvelectrolyte.
In one or more embodiments, the electrodes, anode, cathode, interface layers, electron transporting/hole blocking layers, hole transporting/electron blocking layers of the electronic device can be transparent or semitransparent.
The active layer, electron transporting/hole blocking layers, hole transporting/electron blocking layers of the electronic device may be deposited by solution casting or vapor deposition. Illustrative thin film deposition methods include a spin coating method, a casting method, a microgravure coating method, a gravure coating method, a bar coating method, a roll coating method, a blade coating method, a wire bar coating method, a dip coating method, a spray coating method, a free span coating method, a dye coating method, a screen printing method, a flexo printing method, an offset printing method, an inkjet printing method, a dispenser printing method, a nozzle coating method and a capillary coating method, for forming a film from a solution.
In one or more examples, the active layer has a thickness in a range of 50-600 nm. In some embodiments, the active layer has a thickness in a range of 87-300 nm. In some embodiments, the active layer has a thickness of at least 300 nanometers or in a range of 200 nm to 1 micrometer.
Advantages of organic photosensitive devices include the ability to tune optical and electrical properties for NIR irradiation absorption. Small molecules and polymers which absorb up to NIR wavelengths (Absorption >700 nm) have been reported with improvement of OPV performance due to the enhanced current density from electrical conversion of photon in NIR region.[11-13] Introduction of non-fullerene acceptors has also led to improved performance of organic solar cells beyond the limit of PCBM used in the past.[8-10]
However, conventional organic photovoltaic (OPV) devices face some competition with silicon solar cells and perovskite solar cells in terms of commercial applications as a kind of next generation energy source due to their relatively lower device efficiencies. The present disclosure has surprisingly demonstrated that organic devices according to embodiments described herein can include active region compositions with frontier molecular orbitals and molecular structure tailored for strong absorption profiles (and high device efficiency) in the NIR while maintaining high transparency at visible wavelengths. Such significantly improved transparency is surprising because materials that are more transparent at visible wavelengths are typically also be more transparent at near infrared wavelengths, leading to less desirable photosensitive properties at the near infrared wavelengths. Specifically, is not easy to develop narrow gap donors and acceptors, and it is much harder to develop a combination with good absorptive performance at NIR wavelengths when the bandgaps become narrower and narrower. When the bandgaps become narrower, it is more difficult to achieve the energy offset between HOMOD/HOMOA and the energy offset between LUMOD/LUMOA (see
Moreover, the HOMOs and LUMOs are affected by the molecular conformation (flat, bent etc.) and the environment (crystalline or amorphous domains, surrounded by other donors or acceptors etc.). Thus, in a BHJ the HOMOs and LUMOs are a range instead of a single number. As a result, it is harder to develop new materials that have the right HOMO/LUMO range and energy offset when the bandgaps become narrower and narrower.
The improved transmission of the active regions at visible wavelengths has enabled new devices (e.g., displays with gesture sensors or pulse oximeters) requiring higher transparency at visible wavelengths.
Device and Composition of Matter Examples
Compositions of matter and devices according to embodiments described herein include, but are not limited to, the following.
2. A composition of matter, comprising:
a semiconducting compound of the structure (and isomers thereof):
wherein:
each Ar2 is independently a substituted or non-substituted aromatic functional group, or Ar2 is nothing and the valence of the ring is completed with hydrogen;
each Q is independently O, S Se, or N—R4;
each R and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain;
T is N, C—F, or C—Cl;
X is C, Si, Ge, N or P; and
a non-fullerene acceptor combined with the semiconducting compound.
2. The composition of matter of example 1, wherein the semiconducting compound comprises the structure:
3. The composition of matter of example 2, wherein the semiconducting compound comprises the structure:
4. The composition of matter of example 1, wherein the semiconducting compound comprises the structure:
wherein:
each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain;
T is N, C—F, or C—Cl; and
X is C, Si, Ge, Nor P.
5. The composition of matter of example 1, wherein the semiconducting compound further comprises the structure:
wherein:
each Ar1 is independently a substituted or non-substituted aromatic functional group, or each Ar1 is nothing and the valence of the ring is completed with hydrogen.
each Z is independently O, S, Se, or N—R4;
each R1, R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
each Q is independently O, S Se, or N—R4,
6. The composition of matter of example 5, wherein the semiconducting compound comprises the structure:
7. The composition of matter of example 6, wherein the semiconducting compound comprises the structure:
8. The composition of matter of any of the examples 1-7, wherein the non-fullerene acceptor has the structure:
wherein:
each Ar is independently a substituted or non-substituted aromatic functional group, or each Ar is independently nothing and the valence of its respective thiophene ring is completed with hydrogen;
X is C, Si, Ge, N or P; Y is O, S, Se or N—R3;
Z is O, S, Se, or N—R3;
A is an acceptor moiety; and
each R1, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain: R4 is either a hydrogen or the same as Z—R2.
9. The composition of matter of any of the examples 1-8, wherein the non-fullerene acceptor has a bandgap less than or equal to the bandgap of the semiconducting compound.
10. The composition of matter of any of the examples 1-9, wherein the semiconducting compound comprises a semiconducting polymer having a repeat unit comprising the structure of any of the examples 1-7.
11. The composition of matter of example 10, wherein the semiconducting polymer comprises a semiconducting polymer having the structure:
12. The composition of matter of examples 10 or 11, wherein the acceptor unit in the semiconducting compound is regioregularly arranged along the conjugated main chain section (the side chains comprising C and H, e.g., C10H21 can be any R comprising a substituted or non-substituted alkyl, aryl or alkoxy chain as described herein.
13. The composition of matter of any of the examples 1-12, wherein the non-fullerene acceptor comprises;
wherein R is a solubilizing chain comprising a substituted or non-substituted alkyl, aryl or alkoxy chain and the side chains comprising C and H may be any solubilizing chain comprising a substituted or non-substituted alkyl, aryl or alkoxy chain.
14. The composition of matter of any of the examples 1-13, wherein the non-fullerene acceptor has the structure:
wherein n is an integer; X is C, Si, Ge; EWG=any electron withdrawing group; and each R1 and R2 is independently hydrogen or a substituted or non-substituted alkyl, aryl or alkoxy chain.
15. The composition of matter of any of the examples 1-14, wherein the semiconducting compound comprises a semiconducting small molecule having a repeat unit comprising the structure of any of the examples 1-7.
16. The composition of matter of example 15, wherein the semiconducting compound is a small molecule donor comprising the structure of E-A-(D1-A)n-E, wherein:
D1 is
A is
each R is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain;
X is C, Si, Ge, N or P;
each T is independently C—H, N, C—F or C—Cl;
Q is O, S, Se or N—R4,
E is an alkylated bithiophene, and
n=1, 2 or 3.
17. The composition of matter of any of the examples 1-16, further comprising a bulk heterojunction comprising the composition of matter, wherein the semiconducting compound comprises a donor forming an interconnected network and heterointerface with the non fullerene acceptor, the donor and the acceptor are phase separated, and the donor phase is optionally crystalline. In one or more examples, the NFAs and the donors are combined under conditions to form a blend comprising the donors in first domains and the NFAs in second domains, wherein each of the first domains and second domains are micro or nano sized (e.g., the domains each have a width of 50 nm or less), the first domains and the second domains are sufficiently spatially separated for charge separation of electrons and holes to occur during operation of the solar cell or photodetector (electrons and holes generated in response to incident electromagnetic radiation), but the domains are also sufficiently mixed to form a heterointerface between the donors and the NFAs.
In one or more examples, the first domains and the second domains are not composed of pure donor or pure acceptor phases, respectively, so that the donors and acceptors have sufficient miscibility.
Atomic force microscope images show that is some example blends described herein, the aggregates of donors or acceptor in the blend are relatively small. Conventional devices have suffered from large aggregates of acceptors which easily crystallize using unoptimized molecular structure or film deposition processes. In one or more embodiments described herein, film material structures and compositions and/or processing environment (e.g., solvent, annealing) enable the formation of the donor and acceptor domains that are preferably smaller than 50 nm.
18a. The composition of matter of any of the examples 1-17, wherein the non fullerene acceptor has a bandgap of 1.3 eV or less (e.g., in a range of 0.8 eV-1.3 eV or 1 eV-1.3 eV where eV is electron volts).
19. A device comprising the composition of matter of any of the examples 1-18, wherein the device comprises a solar cell.
20. A device comprising the composition of matter of any of the examples 1-19, wherein the device comprises a photodetector.
21. The device of any of the examples 19-20, further comprising an active region comprising the composition of matter of any of the examples 1-18, wherein holes and electrons are generated in the active region in response to electromagnetic radiation incident on the active region,
the electrons are collected in the non-fullerene acceptor and are transmitted through to a cathode,
the holes are collected in the semiconducting compound comprising a donor and transmitted through to an anode,
so that the device outputs current in response to the electromagnetic radiation.
22. The device of any of the examples 19-21, comprising:
a film comprising a thickness of less than 1 micrometer and comprising:
23. The device of example 22, wherein the composition of matter has the structure:
each Ar1 and Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar1 and Ar2 is nothing and the valence of the ring is completed with hydrogen.
each Z is independently O, S, Se, or N—R4;
each X is C, Si, Ge, N or P;
each Q is independently O, S Se, or N—R4;
and
each R, R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
24. The device of example 23, wherein the semiconducting compound has the structure:
where each R, R2 and R3 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain, and
n is an integer.
25. The device of example 22, further comprising:
a source of the visible electromagnetic radiation;
the photodetector on the source; and
a cover or window on the photodetector, such that the visible electromagnetic radiation is transmitted through the photodetector and the cover or window to a viewer.
26. The device of any of the examples 20-25, further comprising a biomedical sensor, wherein the photodetector measures electromagnetic radiation scattered or reflected from living tissue or cells.
27. A device, comprising:
an active region comprising organic semiconducting compounds (e.g., of any of the examples 1-18) outputting an electrical signal in response to electromagnetic radiation incident on the active region, the active region having:
a thickness less than 1 micrometer;
a transmittivity of at least 70% for the electromagnetic radiation having the wavelength in a range of 400 nanometers (nm) to 600 nm, and
an EQE of at least 30% for the electromagnetic radiation having the wavelength in a range of 700 nm-900 nm.
28. The device of example 27, wherein the semiconducting compound has the structure:
each Ar1 and Ar2 is independently a substituted or non-substituted aromatic functional group, or each Ar1 and Ar2 is nothing and the valence of the ring is completed with hydrogen.
each Z is independently O, S, Se, or N—R4;
each X is C, Si, Ge, N or P;
each Q is independently O, S Se, or N—R4,
and
each R, R1 and R4 is independently hydrogen or a substituted or non-substituted alkyl, aryl, alkoxy or thioether chain.
29. An infrared photodetector, comprising:
a first electrode;
a first carrier transport layer;
an active layer, wherein the first carrier transport layer is between the first electrode and the active layer;
a second carrier transport layer, wherein the active layer is between the first carrier transport layer and the second carrier transport layer; and
a second electrode on the second carrier transport layer, wherein:
the active layer comprises the composition of matter of any of the examples 1-18, and
a transmittance of the photodetector is 50% or more at the wavelengths of 400-600 nm.
30. The photodetector of example 29, wherein the semiconducting compound in the active layer comprises P2.
31. The photodetector of example 29, wherein the semiconducting compound in the active layer comprises PM2.
32. A device comprising the photodetector of any of the examples 29-31, comprising:
a display emitting the wavelengths;
the photodetector on or above the display;
a screen on or above the photodetector, wherein the display is readable by eye of a viewer through the photodetector; and
a circuit connected to the photodetector, the circuit determining a gesture of the viewer from a signal outputted from photodetector in response to infrared radiation incident on the photodetector.
33. The device of example 32, wherein the photodetector has a thickness of 3 micrometers or less.
The following references are incorporated by reference herein
The following references are incorporated by reference herein.
This concludes the description of the preferred embodiment of the present invention. The foregoing description of one or more embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
This application claims the benefit under 35 U.S.C. Section 119(e) of the following co-pending and commonly-assigned applications: U.S. Provisional Patent Application No. 62/866,849, filed Jun. 26, 2019, by Guillermo C Bazan, Jaewon Lee, Seyeong Song, Thuc-Quyen Nguyen, and Seo-Jin Ko, entitled “COMPOSITIONS AND METHODS OF FABRICATION OF NEAR INFRARED PHOTOVOLTAIC DEVICES” Attorney's Docket No. 30794.735-US-P1 (2019-965-1); U.S. Provisional Patent Application No. 63/029,135, filed May 22, 2020, by Guillermo C. Bazan, Jaewon Lee, Seyeong Song, Thuc-Quyen Nguyen, and Seo-Jin Ko, entitled “COMPOSITIONS AND METHODS OF FABRICATION OF NEAR INFRARED PHOTOVOLTAIC DEVICES” Attorney's Docket No. 30794.735-US-P2 (2019-965-2); and U.S. Provisional Patent Application No. 62/965,620, filed Jan. 24, 2020, by Guillermo Bazan, Seyeong Song, Jaewon Lee, and Ziyue Zhu, entitled “NEAR INFRARED (NIR) ORGANIC ELECTRONIC DEVICES” Attorney's Docket No. 30794.760-US-P1 (2020-093-1); all of which applications are incorporated by reference herein. This application is related to the following co-pending an commonly assigned U.S. applications: U.S. Utility patent application Ser. No. 16/179,294, filed Nov. 2, 2018, by Martin Seifrid, Guillermo C. Bazan, Jaewon Lee, Thuc-Quyen Nguyen, and Seo-Jin Ko, entitled “NARROW BANDGAP NON-FULLERENE ACCEPTORS AND DEVICES INCLUDING NARROW BANDGAP NON-FULLERENE ACCEPTORS,” Attorney's Docket No. 30794.657-US-U1 (2018-083), which application claims the benefit under 35 USC 119(e) of U.S. Provisional Patent Application No. 62/580,710, filed Nov. 2, 2017, by Martin Seifrid, Guillermo C. Bazan, Jaewon Lee, Thuc-Quyen Nguyen, and Seo-Jin Ko, entitled “NARROW BANDGAP NON-FULLERENE ACCEPTORS AND DEVICES INCLUDING NARROW BANDGAP NON-FULLERENE ACCEPTORS,” Attorney's Docket No. 30794.657-US-P1 (2018-083); U.S. Utility patent application Ser. No. 16/792,000, filed Feb. 14, 2020, by Jaewon Lee, Seo-Jin Ko, Jianfei Huang, Martin Seifrid, Hengbin Wang, Thuc-Quyen Nguyen, and Guillermo C. Bazan, entitled “ORGANIC SOLAR CELL AND PHOTODETECTOR MATERIALS AND DEVICES” Attorney's Docket No. 30794.717-US-U1 (2019-400-1), which application claims the benefit under 35 USC 119(e) of U.S. Provisional Patent Application No. 62/806,232, filed Feb. 15, 2019, by Jaewon Lee, Seo-Jin Ko, Jianfei Huang, Martin Seifrid, Hengbin Wang, Thuc-Quyen Nguyen, and Guillermo C. Bazan, entitled “ORGANIC SOLAR CELL AND PHOTODETECTOR MATERIALS AND DEVICES” Attorney's Docket No. 30794.717-US-P1 (2019-400-1); and U.S. Provisional Patent Application No. 62/866,797, filed Jun. 26, 2019, by Thuc-Quyen Nguyen. Jianfei Huang. Jaewon Lee, Guillermo C Bazan, and Hengbin Wang, entitled “ORGANIC SOLAR CELL AND PHOTODETECTOR MATERIALS AND DEVICES” Attorney's Docket No. 30794.734-US-P1 (2019-937-1); all of which applications are incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US20/39963 | 6/26/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 63029135 | May 2020 | US | |
| 62965620 | Jan 2020 | US | |
| 62866849 | Jun 2019 | US |
