Patent Application
20150028290
The claimed invention was made by, on behalf of, and/or in connection with one or more of the following parties to a joint university corporation research agreement: Regents of the University of Michigan, Princeton University, University of Southern California, and the Universal Display Corporation. The agreement was in effect on and before the date the claimed invention was made, and the claimed invention was made as a result of activities undertaken within the scope of the agreement.
The present invention relates to compounds for use as emitters and devices, such as organic light emitting diodes, including the same. More particularly, the compounds disclosed herein are novel heteroleptic bistridentate osmium carbene complexes and a novel synthetic method to make both homoleptic and heteroleptic bistridentate osmium carbene complexes.
Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants.
OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting. Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.
One application for phosphorescent emissive molecules is a full color display. Industry standards for such a display call for pixels adapted to emit particular colors, referred to as “saturated” colors. In particular, these standards call for saturated red, green, and blue pixels. Color may be measured using CIE coordinates, which are well known to the art.
One example of a green emissive molecule is tris(2-phenylpyridine) iridium, denoted Ir(ppy)3, which has the following structure:
In this, and later figures herein, we depict the dative bond from nitrogen to metal (here, Ir) as a straight line.
As used herein, the term “organic” includes polymeric materials as well as small molecule organic materials that may be used to fabricate organic opto-electronic devices. “Small molecule” refers to any organic material that is not a polymer, and “small molecules” may actually be quite large. Small molecules may include repeat units in some circumstances. For example, using a long chain alkyl group as a substituent does not remove a molecule from the “small molecule” class. Small molecules may also be incorporated into polymers, for example as a pendent group on a polymer backbone or as a part of the backbone. Small molecules may also serve as the core moiety of a dendrimer, which consists of a series of chemical shells built on the core moiety. The core moiety of a dendrimer may be a fluorescent or phosphorescent small molecule emitter. A dendrimer may be a “small molecule,” and it is believed that all dendrimers currently used in the field of OLEDs are small molecules.
As used herein, “top” means furthest away from the substrate, while “bottom” means closest to the substrate. Where a first layer is described as “disposed over” a second layer, the first layer is disposed further away from substrate. There may be other layers between the first and second layer, unless it is specified that the first layer is “in contact with” the second layer. For example, a cathode may be described as “disposed over” an anode, even though there are various organic layers in between.
As used herein, “solution processible” means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.
A ligand may be referred to as “photoactive” when it is believed that the ligand directly contributes to the photoactive properties of an emissive material. A ligand may be referred to as “ancillary” when it is believed that the ligand does not contribute to the photoactive properties of an emissive material, although an ancillary ligand may alter the properties of a photoactive ligand.
As used herein, and as would be generally understood by one skilled in the art, a first “Highest Occupied Molecular Orbital” (HOMO) or “Lowest Unoccupied Molecular Orbital” (LUMO) energy level is “greater than” or “higher than” a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Since ionization potentials (IP) are measured as a negative energy relative to a vacuum level, a higher HOMO energy level corresponds to an IP having a smaller absolute value (an IP that is less negative). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) having a smaller absolute value (an EA that is less negative). On a conventional energy level diagram, with the vacuum level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A “higher” HOMO or LUMO energy level appears closer to the top of such a diagram than a “lower” HOMO or LUMO energy level.
As used herein, and as would be generally understood by one skilled in the art, a first work function is “greater than” or “higher than” a second work function if the first work function has a higher absolute value. Because work functions are generally measured as negative numbers relative to vacuum level, this means that a “higher” work function is more negative. On a conventional energy level diagram, with the vacuum level at the top, a “higher” work function is illustrated as further away from the vacuum level in the downward direction. Thus, the definitions of HOMO and LUMO energy levels follow a different convention than work functions.
More details on OLEDs, and the definitions described above, can be found in U.S. Pat. No. 7,279,704, which is incorporated herein by reference in its entirety.
According to an aspect of the present disclosure, a method of making an osmium(II) complex having Formula I
L1-Os-L2, wherein L1 and L2 are independently a biscarbene tridentate ligand, wherein L1 and L2 can be same or different is disclosed. The method comprises: (a) reacting a precursor of ligand L1 with an osmium precursor to form an intermediate product, wherein the osmium precursor having the formula OsHx(PR3)y, wherein x is an integer from 2 to 6 and y is an integer from 2 to 5, and R is selected from the group consisting of aryl, alkyl and cycloalkyl; and (b) reacting a precursor of ligand L2 with said intermediate product.
In one embodiment of the method, L1 and L2 are monoanionic ligands. In some embodiments, L1 and L2 are independently selected from ligands having Formula II:
wherein Y1, Y2 and Y3 comprise C or N; wherein R3 and R4 may represent mono-, or di-substitutions, or no substitution; wherein R5 may represent mono-, di-, or tri-substitutions, or no substitution; wherein R1, R2, R3, R4 and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein any two adjacent substituents of R1, R2, R3, R4 and R5 are optionally joined to form a ring; and wherein the dash lines show the connection points to osmium.
According to an embodiment, a compound having the structure according to Formula I as defined herein is disclosed.
According to another aspect of the present disclosure, a first device comprising a first organic light emitting device is disclosed. The first organic light emitting device comprises an anode; a cathode; and an organic layer, disposed between the anode and the cathode. The organic layer can comprise a compound having the structure according Formula I
The novel compounds, heteroleptic bistridentate osmium carbene complexes, and a novel synthetic method to make both homoleptic and heteroleptic bistridentate osmium carbene complexes disclosed herein are useful as emitters in organic light emitting devices. The inventors have discovered that the incorporation of these ligands can narrow the emission spectrum and improve device efficiency.
Generally, an OLED comprises at least one organic layer disposed between and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer(s). The injected holes and electrons each migrate toward the oppositely charged electrode. When an electron and hole localize on the same molecule, an “exciton,” which is a localized electron-hole pair having an excited energy state, is formed. Light is emitted when the exciton relaxes via a photoemissive mechanism. In some cases, the exciton may be localized on an excimer or an exciplex. Non-radiative mechanisms, such as thermal relaxation, may also occur, but are generally considered undesirable.
The initial OLEDs used emissive molecules that emitted light from their singlet states (“fluorescence”) as disclosed, for example, in U.S. Pat. No. 4,769,292, which is incorporated by reference in its entirety. Fluorescent emission generally occurs in a time frame of less than 10 nanoseconds.
More recently, OLEDs having emissive materials that emit light from triplet states (“phosphorescence”) have been demonstrated. Baldo et al., “Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices,” Nature, vol. 395, 151-154, 1998; (“Baldo-I”) and Baldo et al., “Very high-efficiency green organic light-emitting devices based on electrophosphorescence,” Appl. Phys. Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporated by reference in their entireties. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporated by reference.
More examples for each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Pat. No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003/0230980, which is incorporated by reference in its entirety. Examples of emissive and host materials are disclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which is incorporated by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. Patent Application Publication No. 2003/0230980, which is incorporated by reference in its entirety. U.S. Pat. Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entireties, disclose examples of cathodes including compound cathodes having a thin layer of metal such as Mg:Ag with an overlying transparent, electrically-conductive, sputter-deposited ITO layer. The theory and use of blocking layers is described in more detail in U.S. Pat. No. 6,097,147 and U.S. Patent Application Publication No. 2003/0230980, which are incorporated by reference in their entireties. Examples of injection layers are provided in U.S. Patent Application Publication No. 2004/0174116, which is incorporated by reference in its entirety. A description of protective layers may be found in U.S. Patent Application Publication No. 2004/0174116, which is incorporated by reference in its entirety.
The simple layered structure illustrated in
Structures and materials not specifically described may also be used, such as OLEDs comprised of polymeric materials (PLEDs) such as disclosed in U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated by reference in its entirety. By way of further example, OLEDs having a single organic layer may be used. OLEDs may be stacked, for example as described in U.S. Pat. No. 5,707,745 to Forrest et al, which is incorporated by reference in its entirety. The OLED structure may deviate from the simple layered structure illustrated in
Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties, organic vapor phase deposition (OVPD), such as described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety, and deposition by organic vapor jet printing (OVJP), such as described in U.S. Pat. No. 7,431,968, which is incorporated by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, and patterning associated with some of the deposition methods such as ink jet and OVJD. Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having 20 carbons or more may be used, and 3-20 carbons is a preferred range. Materials with asymmetric structures may have better solution processibility than those having symmetric structures, because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.
Devices fabricated in accordance with embodiments of the present invention may further optionally comprise a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment including moisture, vapor and/or gases, etc. The barrier layer may be deposited over, under or next to a substrate, an electrode, or over any other parts of a device including an edge. The barrier layer may comprise a single layer, or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include compositions having a single phase as well as compositions having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate an inorganic or an organic compound or both. The preferred barrier layer comprises a mixture of a polymeric material and a non-polymeric material as described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos. PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporated by reference in their entireties. To be considered a “mixture”, the aforesaid polymeric and non-polymeric materials comprising the barrier layer should be deposited under the same reaction conditions and/or at the same time. The weight ratio of polymeric to non-polymeric material may be in the range of 95:5 to 5:95. The polymeric material and the non-polymeric material may be created from the same precursor material. In one example, the mixture of a polymeric material and a non-polymeric material consists essentially of polymeric silicon and inorganic silicon.
Devices fabricated in accordance with embodiments of the invention may be incorporated into a wide variety of consumer products, including flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads up displays, fully transparent displays, flexible displays, laser printers, telephones, cell phones, personal digital assistants (PDAs), laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, vehicles, a large area wall, theater or stadium screen, or a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as 18 degrees C. to 30 degrees C., and more preferably at room temperature (20-25 degrees C.), but could be used outside this temperature range, for example, from −40 degree C. to +80 degree C.
The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may employ the materials and structures. More generally, organic devices, such as organic transistors, may employ the materials and structures.
The terms halo, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group, aryl, aromatic group, and heteroaryl are known to the art, and are defined in U.S. Pat. No. 7,279,704 at cols. 31-32, which are incorporated herein by reference.
As used herein, “substituted” indicates that a substituent other than H is bonded to the relevant carbon. Thus, where R2 is monosubstituted, then one R2 must be other than H. Similarly, where R3 is disubstituted, then two of R3 must be other than H. Similarly, where R2 is unsubstituted R2 is hydrogen for all available positions.
In the present disclosure, novel heteroleptic bistridentate Os(II) complexes and a novel method for synthesizing both homoleptic and heteroleptic bistridentate Os(II) complexes is provided. Heteroleptic osmium complexes provide great freedom of tuning emission color, electrochemical energy levels, and improving evaporation properties.
Osmium (II) complexes have been investigated for OLED applications. The octahedral ligand arrangement of the Os(II) complexes resembles that of Ir(III) complexes. Os(II) complexes generally exhibit low oxidation potential, i.e. shallow HOMO energy level than Ir(III) complexes. The inventors have discovered that bistridentate Os(II) carbene complexes offer performance advantages for OLED applications. Without being bound to a theory, the inventors believe that the rigid nature of the tridentate ligands are providing narrow emission line widths and short excited state lifetimes, which can result in better color purity and longer device lifetime, making them suitable for display applications.
US2005260449 and WO2009046266 disclosed bistridentate Os(II) complexes. Examples of homoleptic Os(II) complexes were provided. The two tridentate ligands binding to Os(II) metal are identical. It may be beneficial to incorporate two different ligands to Os(II) metal to form a heterlopetic complex. For example, the thermal properties, electrochemical properties, and photophysical properties can be tuned by selecting two proper ligands. It offers more flexibility for materials design than two identical ligands.
The synthesis of homoleptic complexes, however, has been challenging; let alone the heteroleptic complexes. The synthesis method used in WO2009046266 generated very low yield, typically 2-5%. In a later application, US2012215000, the yield was significantly improved to over 30% using a new osmium precursor. In theory, both of these methods should work for synthesis of heteroleptic bistridentate Os(II) complexes by introducing two different ligands at the complexation stage and isolating the desired heteroleptic complex from the reaction mixture. The synthesis will be extremely inefficient and impractical.
The inventors have developed a new stepwise complexation method. This method is suitable for making both homoleptic and heteroleptic bistridentate Os(II) complexes. As shown in the scheme below, an osmium precursor was first reacted with a bistridentate ligand to generate an intermediate that has one tridentate ligand coordinated to the metal. The intermediate was then treated with another tridentate ligand to generate the final complex. Depending on the structure of the second ligand, homoleptic or heteroleptic complexes can be synthesized. In addition, the yield was improved. One example of the inventive synthetic method is shown below:
In describing the novel synthesis method of the inventors, all reactions were carried out with rigorous exclusion of air using Schlenk-tube techniques. Solvents, except DMF and acetonitrile that were dried and distilled under argon, were obtained oxygen- and water-free from an MBraun solvent purification apparatus. 1H, 31P{1H}, 19F and 13C{1H} NMR spectra were recorded on Bruker 300 ARX, Bruker Avance 300 MHz, and Bruker Avance 400 MHz instruments. Chemical shifts (expressed in parts per million) are referenced to residual solvent peaks (1H, 13C {1H}) or external 85% H3PO4 (31P {1H}), or external CFCl3 (19F). Coupling constants J and N are given in hertz. Attenuated total reflection infrared spectra (ATR-IR) of solid samples were run on a Perkin-Elmer Spectrum 100 FT-IR spectrometer. C, H, and N analyses were carried out in a Perkin-Elmer 2400 CHNS/O analyzer. High-resolution electrospray mass spectra were acquired using a MicroTOF-Q hybrid quadrupole time-of-flight spectrometer (Bruker Daltonics, Bremen, Germany). OsH6(PiPr3)2 was prepared by the method published in Aracama, M.; Esteruelas, M. A.; Lahoz, F. J.; López, J. A.; Meyer, U.; Oro, L. A.; Werner, H. Inorg. Chem. 1991, 30, 288.
Preparation of Dihydride-BF4
A solution of OsH6(PiPr3)2 (261 mg, 0.505 mmol) in dimethylformamide (DMF) (5 mL) was treated with 1,3-bis[(1-methyl)benzylimidazolium-3-yl]benzene diiodide (300 mg, 0.505 mmol). The resulting mixture was refluxed for 20 min, getting a very dark solution. After cooling at room temperature the solvent was removed in vacuo, affording a dark residue. The residue was dissolved in acetonitrile (10 mL) and AgBF4 (98.3 mg, 0.505 mmol) was added. After stirring protected from the light for 30 min the resulting suspension was filtered through Celite to remove the silver salts. The solution thus obtained was evaporated to ca. 0.5 mL and diethyl ether (10 mL) was added to afford a beige solid, that was washed with further portions of diethyl ether (2×2 mL) and dried in vacuo. Yield: 240 mg (50%). Analytical Calculation for C40H61BF4N4OsP2: C, 51.28; H, 6.56; N, 5.98. Found: C, 51.55; H, 6.70; N, 5.62. HRMS (electrospray, m/z): calcd for C40H61N4OsP2 [M]+: 851.3983; found: 851.4036. IR (cm−1): v(Os—H) 2104 (w), v(BF4) 1080-1000 (vs). 1H NMR (300 MHz, CD3CN, 298K): δ 8.31 (m, 2H, CH bzm), 7.98 (d, JH-H=7.9, 2H, CH Ph), 7.70 (m, 2H, CH bzm), 7.57 (t, JH-H=7.9, 1H, CH Ph), 7.54-7.50 (m, 4H, CH bzm), 4.32 (s, 6H, CH3), 1.54 (m, 6H, PCH(CH3)2), 0.67 (dvt, JHH=6.2, N=13.2, 36H, PCH(CH3)2), −6.25 (t, JH-P=13.6, 2H, Os—H). 13C {1H} NMR (75.42 MHz, CD3CN, 293K): δ 189.4 (t, JC-P=7.5, NCN), 161.3 (Os—C), 146.9 (s, CPh), 137.3 (s, CBzm), 132.8 (s, C Bzm), 124.9 (s, CH Bzm), 124.5 (s, CH Bzm), 124.2 (s, CH Ph), 112.8 (s, CH Bzm), 111.9 (s, CH Bzm), 109.2 (s, CH Ph), 38.9 (s, CH3), 29.3 (t, N=27, PCH(CH3)2), 18.5 (s, PCH(CH3)2). 31P{1H} NMR (121.4 MHz, CD3CN, 293K): δ 4.5 (s).
Preparation of Complex Monohydride, Shown Below:
This monohydride compound can be prepared by using two different methods. Method (A): A solution of OsH6(PiPr3)2 (261 mg, 0.505 mmol) in DMF (5 mL) was treated with 1,3-bis[(1-methyl)benzylimidazolium-3-yl]benzene diiodide (300 mg, 0.505 mmol). The resulting mixture was refluxed for 20 min, getting a very dark solution. After cooling at room temperature the solvent was removed in vacuo, affording a dark residue. The dark residue was dissolved in 10 mL of tetrahydrofuran (THF) and KtBuO (142 mg, 1.263 mmol) was added to the solution. After stirring at room temperature for 10 min the resulting suspension was filtered through Celite to remove the potassium salts. The solution thus obtained was evaporated to dryness to afford a yellow residue. Addition of pentane afforded a yellow solid, which was washed with pentane (1×2 mL) and dried in vacuo to obtain a yellow solid. Yield: 378 mg (88%). Method (B): A solution of dihydride-BF4 (200 mg, 0.213 mmol) in THF (5 mL) was treated with KtBuO (28.6 mg, 0.255 mmol). After stirring at room temperature for 10 min the resulting suspension was filtered through Celite to remove the potassium salts. The solution thus obtained was evaporated to dryness to afford a yellow residue. Addition of pentane afforded a yellow solid, which was washed with pentane (1×2 mL) and dried in vacuo obtain a yellow solid. Yield: 163 mg (90%). Anal. Calcd. for C40H60N4OsP2: C, 56.58; H, 7.12; N, 6.60. Found: C, 56.00; H, 6.69; N, 6.76. HRMS (electrospray, m/z): calcd. For [M+H]+ 851.3983; found: 851.3979. IR (cm−1): v(Os—H) 1889 (w). 1H NMR (300 MHz, C6D6, 298K): δ 8.17 (d, JH-H=7.7, 2H, CH Ph), 8.06 (d, JH-H=7.7, 2H, CH bzm), 7.60 (t, JH-H=7.7, 1H, CH Ph), 7.20 (td, JH-H=7.9, JH-H=1.0, 2H, CH bzm), 7.14-7.03 (m, 4H CH bzm), 3.92 (s, 6H, CH3), 1.55 (m, 6H, PCH(CH3)2), 0.67 (dvt, JH-H=6.9, N=12.3, 36H, PCH(CH3)2), −9.55 (t, JH-P=33.6, 1H, Os—H). 13C {1H} NMR (75.42 MHz, C6D6, 293K): δ 197.6 (t, JC-P=9.2, Os—NCN), 173.2 (t, JC-P=2.9, Os—C), 148.4 (s, CPh), 137.3 (s, C Bzm), 134.4 (s, CBzm), 121.5 (s, CH Bzm), 121.2 (s, CH Bzm), 117.9 (s, CH Ph), 109.6 (s, CH Bzm), 108.5 (s, CH Bzm), 105.8 (s, CH Ph), 37.9 (s, CH3), 31.0 (t, N=24.2, PCH(CH3)2), 19.7 (s, PCH(CH3)2). 31P {1H} NMR (121.4 MHz, C6D6, 293K): δ 20.6 (s, doublet under off resonance conditions).
Preparation of Complex Monohydride-CF3:
Method (A): A solution of dihydride-CF3-BF4 (200 mg, 0.2 mmol) in THF (5 mL) was treated with KtBuO (26.8 mg, 0.24 mmol). After stirring at room temperature for 10 min the resulting suspension was filtered through Celite to remove the potassium salts. The solution thus obtained was evaporated to dryness to afford a yellow residue. Addition of pentane afforded a yellow solid, which was washed with pentane (1×2 mL) and dried in vacuo obtain a yellow solid. Yield: 240 mg (50%). Anal. Calcd. for C4H59F3N4OsP2: C, 53.69; H, 6.48; N, 6.11. Found: C, 53.20; H, 6.33; N, 6.18. IR (cm−1): v(Os—H) 1842 (w). 1H NMR (300 MHz, C6D6, 298K): δ 8.53 (s, 2H, CH Ph-CF3), 8.18 (m, 2H, CH bzm), 7.15-6.98 (m, 6H, CH bzm), 3.86 (s, 6H, CH3), 1.49 (m, 6H, PCH(CH3)2), 0.60 (dvt, JH.H=6.6, N=12.9, 36H, PCH(CH3)2), −9.29 (t, JH-P=34.0, 1H, Os—H). 13C {1H} NMR (75.42 MHz, C6D6, 293K): δ 197.4 (t, JC-P=9.0, Os—NCN), 173.2 (t, JC-P=3.6, Os—C), 148.0 (s, CPh), 137.2 (s, CBzm), 133.9 (s, CBzm), 128.2 (q, JC-F=270.0, CF3), 122.0 (s, CH Bzm), 121.7 (s, CH Bzm), 118.9 (q, JC-F=30.8, C—CF3), 109.8 (s, CH Bzm), 108.7 (s, CH Bzm), 102.0 (q, JC-F=4.0 CH Ph), 37.9 (s, CH3), 30.9 (t, N=24.8, PCH(CH3)2), 19.5 (s, PCH(CH3)2). 31P {1H} NMR (121.4 MHz, C6D6, 293K): δ 21.4 (s, doublet under off resonance conditions). 19F NMR 282 MHz, C6D6, 293K): 6-60.10 (CF3). Method (B): A solution of OsH6(PiPr3)2 (235 mg, 0.455 mmol) in DMF (5 mL) was treated with 1,3-bis[(1-methyl)benzylimidazolium-3-yl]-5-trifluoromethyl-benzene diiodide (300 mg, 0.455 mmol). The resulting mixture was refluxed for 20 min, getting a very dark solution. After cooling at room temperature the solvent was removed in vacuo, affording a dark residue. The addition of 4 mL of toluene caused the precipitation of a brown solid that was washed with further portions of diethyl ether (2×4 mL). The brown solid was dissolved in THF (10 mL) and KtBuO (102 mg, 0.906 mmol) was added. After stirring for 20 min the resulting suspension was filtered through Celite to remove the iodide salts. The solution thus obtained was evaporated to dryness and pentane (4 mL) was added to afford an orange solid that was washed with further portions of pentane (1×3 mL) and dried in vacuo. This orange solid was suspended in diethyl ether (10 mL) and treated with HBF4:Et2O (93 μL, 0.680 mmol) getting a white suspension. This solid was decanted, washed with further portions of diethyl ether (2×4 mL) and dried in vacuo. Yield: 405 mg (89%) Anal. Calcd. for C41H60BF7N4OsP2: C, 49.00; H, 6.02; N, 5.58. Found: C, 49.21; H, 5.79; N, 5.69. HRMS (electrospray, m/z): calcd for [M]+: 919.3857; found: 919.4035. IR (cm−1): v(Os—H) 2097 (w), v(BF4) 1080-1000 (vs). 1H NMR (300 MHz, CD3CN, 298K): δ 9.60 (m, 2H, CH bzm), 9.41 (s, 2H, CH Ph), 8.96 (m, 2H, CH bzm), 8.80 (m, 4H, CH bzm), 5.57 (s, 6H, CH3), 2.80 (m, 6H, CHP), 1.91 (dvt, 36H, JHH=7.1, N=13.5, CH3-P), −4.70 (t, 2H, JH-P=13.5, Hhyd); 13C {1H}NMR (75.42 MHz, CD3CN, 293K): δ 189.6 (t, JC-P=7.5, NCN), 169.6 (t, JC-P=5.7, Os—C), 146.7 (s, C Ph), 137.4 (s, C Bzm), 132.6 (s, C Bzm), 126.7 (q, JC-F=270, CF3), 126.3 (q, JC-F=28.6, CCF3), 125.4 (s, CH Bzm), 125.1 (s, CH Bzm), 113.2 (s, CH Bzm), 112.3 (s, CH Bzm), 105.6 (q, JC-F=3.9, CH Ph), 39.1 (s, CH3), 29.5 (t, N=13.5, PCH(CH3)2), 19.6 (s, PCH(CH3)2). 31P {1H} NMR (121.4 MHz, CD3CN, 293K): δ 5.2 (s). 19F {1H} NMR (282 MHz, CD3CN, 293K): δ−60.21 (s, CF3); −151.7 (broad signal, BF4)
Preparation of Complex A:
Monohydride (250 mg, 0.294 mmol) and 1,3-bis[(1-methyl)benzylimidazolium-3-yl]benzene ditetrafluoroborate (181 mg, 0.353 mmol) were dissolved in 5 mL of DMF and triethyl amine (0.6 mL, 4.4 mmol) was added to the solution. The resulting mixture was refluxed for 1.5 h and then it was cooled to room temperature. The solvent was evaporated under vacuum to afford a brown residue. Addition of acetonitrile afforded a bright yellow solid that was washed with acetonitrile (1×2 mL) and dried in vacuo. Yield: 153 mg (60%). HRMS (electrospray, m/z): calcd for C44H34N8Os [M]+: 867.2562; found: 867.2597. 1H NMR (300 MHz, C6D6, 293K): δ 8.29 (d, JH-H=7.7, 4H, CH Ph), 8.18 (d, JH-H=7.9, 4H, CH bzm), 7.81 (t, JH-H=7.7, 2H, CH Ph), 7.08 (td, JH-H=7.9, JH-H=1.0, 4H, CH bzm), 6.80 (td, JH-H=7.9, JH-H=1.0, 4H, CH bzm), 6.18 (d, JH-H=7.9, 4H, CH bzm), 2.25 (s, 12H, CH3). 13C {1H} NMR (75.42 MHz, C6D6, 293K): δ 192.6 (s, Os—NCN), 171.1 (s, Os—C), 146.8 (s, CPh), 137.2 (s, CBzm), 133.4 (s, CBzm), 121.43 (s, CH Bzm), 121.03 (s, CH Bzm), 117.8 (s, CH Ph), 109.9 (s, CH Bzm), 109.0 (s, CH Bzm), 106.4 (s, CH Ph), 32.7 (s, CH3).
Preparation of Complex A-CF3:
Monohydride (250 mg, 0.294 mmol) and 1,3-bis[(1-methyl)benzylimidazolium-3-yl]-5-trifluoromethyl-benzene ditetrafluoroborate (170 mg, 0.294 mmol) were dissolved in 5 mL of DMF and triethyl amine (0.6 mL, 4.4 mmol) was added to the solution. The resulting mixture was refluxed for 1.5 h and then it was cooled to room temperature. The solvent was evaporated under vacuum to afford a brown residue. Addition of acetonitrile afforded a bright yellow solid that was washed with acetonitrile (1×2 mL) and dried in vacuo. Yield: 147 mg (53%). HRMS (electrospray, m/z): calcd for C45H33F3N8Os [M]+: 934.2392; found: 934.2398. 1H NMR (300 MHz, C6D6, 293K): δ 8.75 (s, 2H, CH Ph-CF3), 8.24 (d, JH-H=7.8, 2H, CH Ph), 8.16 (d, JH-H=7.8, 2H, CH bzm), 8.14 (d, JH-H=7.8, 2H, CH bzm), 7.78 (t, JH-H=7.8, 1H, CH Ph), 7.08 (t, JH-H=7.8, 2H, CH bzm), 6.99 (t, JH-H=7.8, 2H, CH bzm), 6.81 (t, JH-H=7.9, 2H, CH bzm), 6.78 (t, JH-H=7.9, 2H, CH bzm), 6.21 (d, JH-H=7.8, 2H, CH bzm), 6.14 (d, JH-H=7.8, 2H, CH bzm), 2.22 (s, 6H, CH3), 2.11 (s, 6H, CH3). 13C {1H} NMR (100.63 MHz, C6D6, 293K): δ 192.4 (s, Os—NCN), 192.1 (s, Os—NCN), 179.0 (s, Os—C), 170.1 (s, Os—C), 146.7 (s, CPh), 146.5 (s, CPh), 137.2 (s, CBzm), 137.1 (s, CBzm), 133.4 (s, CBzm), 133.2 (s, CBzm), 128.4 (q, JC-F=270.4 Hz, CF3) 122.0 (s, CH Bzm), 121.8 (s, CH Bzm), 121.7 (s, CH Bzm), 121.4 (s, CH Bzm), 119.0 (q, JC-F=30.7 Hz, CCF3) 118.5 (s, CH Ph), 110.14 (s, CH Bzm), 110.08 (s, CH Bzm), 109.30 (s, CH Bzm), 109.28 (s, CH Bzm), 107.0 (s, CH Ph), 103.1 (q, JC-F=3.8 Hz, CHPh), 32.8 (s, CH3), 32.7 (s, CH3). 19F NMR (282 MHz, C6D6, 293K): δ −57.1 (CF3).
According to an aspect of the present disclosure, a method of making an osmium(II) complex having Formula I
L1-Os-L2, wherein L1 and L2 are independently a biscarbene tridentate ligand, wherein L1 and L2 can be same or different is disclosed. The method comprises: (a) reacting a precursor of ligand L1 with an osmium precursor to form an intermediate product, wherein the osmium precursor having the formula OsHx(PR3)y, wherein x is an integer from 2 to 6 and y is an integer from 2 to 5, and R is selected from the group consisting of aryl, alkyl and cycloalkyl; and (b) reacting a precursor of ligand L2 with said intermediate product.
In one embodiment of the method, L1 and L2 are monoanionic ligands. In some embodiments, L1 and L2 are independently selected from ligands having Formula II:
wherein Y1, Y2 and Y3 comprise C or N; wherein R3 and R4 may represent mono-, or di-substitutions, or no substitution; wherein R5 may represent mono-, di-, or tri-substitutions, or no substitution; wherein R1, R2, R3, R4 and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein any two adjacent substituents of R1, R2, R3, R4 and R5 are optionally joined to form a ring; and wherein the dash lines show the connection points to osmium.
In one embodiment of the method, Y1, Y2 and Y3 comprise C. In one embodiment, Y1 and Y3 comprise C, and Y2 is N. In one embodiment, Y1 and Y3 are N, and Y2 comprise C. In one embodiment, R1 and R2 are independently selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl, and partially or fully deuterated variants thereof. In one embodiment, R1 and R2 are independently selected from the group consisting of methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclopentyl, cyclohexyl, partially or fully deuterated variants thereof, and combinations thereof.
In one embodiment of the method, the osmium precursor having the formula OsH6(PR3)2. In another embodiment, R in the osmium precursor having the formula OsH6(PR3)y is selected from the group consisting of methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, cyclohexyl, phenyl, 2,6-dimethylphenyl, and 2-methylphenyl. In other embodiment, R is 1-methylethyl.
In another embodiment, the ligands having Formula II are selected from the group consisting of:
According to an embodiment, a compound having a structure according to Formula I, L1-Os-L2 is provided, wherein L1 and L2 are different; wherein L1 and L2 are independently selected from ligands having Formula II,
In Formula II, Y1, Y2 and Y3 comprise C or N; wherein R3 and R4 may represent mono-, or di-substitutions, or no substitution; wherein R5 may represent mono-, di-, or tri-substitutions, or no substitution; wherein R1 and R2 are independently selected from the group consisting of alkyl and cycloalkyl; wherein R3, Wand R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, and combinations thereof; wherein any two adjacent substituents of R1, R2, R3, R4 and R5 are optionally joined to condense into a fused ring; and wherein the dash lines show the connection points to osmium.
In an embodiment of the compound, Y1, Y2 and Y3 comprise C. In one embodiment of the compound, Y1 and Y3 comprise C, and Y2 is N. In some embodiments, Y1 and Y3 are N, and Y2 comprise C. In one embodiment, R1 and R2 are independently selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl, and partially or fully deuterated variants thereof. In one embodiment, R1 and R2 are independently selected from the group consisting of methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclopentyl, cyclohexyl, partially or fully deuterated variants thereof, and combinations thereof.
In some embodiments of the compound, L1 and L2 are independently selected from ligands having Formula III:
wherein X1, X2, X3, X4, X5, X6, X7 and X8 comprise C or N. In one embodiment, X1, X2, X3, X4, X5, X6, X7 and X8 comprise C.
In some embodiments, the ligands having Formula II are selected from the group consisting of: L101 to L159 defined herein.
In some embodiments, the compound having a structure according to Formula I, L1-Os-L2 is selected from the group consisting of Compounds 1 to 1159 defined in Table 1 below:
In one embodiment, a first device comprising a first organic light emitting device is disclosed. The first organic light emitting device comprises an anode; a cathode; and an organic layer, disposed between the anode and the cathode, comprising a compound having the structure according Formula I, L1-Os-L2; wherein L1 and L2 are different; wherein L1 and L2 are independently selected from ligands having Formula II:
wherein Y1, Y2 and Y3 comprise C or N; wherein R3 and R4 may represent mono-, or di-substitutions, or no substitution; wherein R5 may represent mono-, di-, or tri-substitutions, or no substitution; wherein R1 and R2 are independently selected from the group consisting of alkyl and cycloalkyl; wherein R3, R4 and R5 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, and combinations thereof; wherein any two adjacent substituents of R1, R2, R3, R4 and R5 are optionally joined to condense into a fused ring; and wherein the dash lines show the connection points to osmium.
In one embodiment of the first device, Y1, Y2 and Y3 comprise C. In one embodiment, Y1, Y2 and Y3 are N. In one embodiment, R1 and R2 are independently selected from the group consisting of methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclopentyl, cyclohexyl, partially or fully deuterated variants thereof, and combinations thereof.
In some embodiments of the first device, L1 and L2 are independently selected from ligands having Formula III:
wherein X1, X2, X3, X4, X5, X6, X7 and X8 comprise C or N. In some embodiments, X1, X2, X3, X4, X5, X6, X7 and X8 comprise C.
In some embodiments of the first device, the ligands having Formula II are selected from the group consisting of L101 to L159 defined herein.
In some embodiments of the first device, the first emitting compound is selected from the group consisting of Compounds 1 to 1159 defined in Table 1.
The first device can be one or more of a consumer product, an organic light-emitting device, and/or a lighting panel.
The organic layer in the organic light emitting device can be an emissive layer and the compound can be an emissive dopant in some embodiments, while the compound can be a non-emissive dopant in other embodiments.
The organic layer can also include a host. In some embodiments, the host can include a metal complex. In one embodiment, the host can be a metal 8-hydroxyquinolate. The host can be a triphenylene containing benzo-fused thiophene or benzo-fused furan. Any substituent in the host can be an unfused substituent independently selected from the group consisting of CnH2n+1, OCnH2+1, OAr1, N(CnH2+1)2, N(Ar1)(Ar2), CH═CH—CnH2n+1, C≡C—CnH2+1, Ar1, Ar1—Ar2, CnH2n—Ar1, or no substitution. In the preceding substituents n can range from 1 to 10; and Ar1 and Ar2 can be independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.
The host can be a compound selected from the group consisting of carbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene. The “aza” designation in the fragments described above, i.e., aza-dibenzofuran, aza-dibenzonethiophene, etc., means that one or more of the C—H groups in the respective fragment can be replaced by a nitrogen atom, for example, and without any limitation, azatriphenylene encompasses both dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. One of ordinary skill in the art can readily envision other nitrogen analogs of the aza-derivatives described above, and all such analogs are intended to be encompassed by the terms as set forth herein. The host can include a metal complex. The host can be a specific compound selected from the group consisting of:
and combinations thereof.
In yet another aspect of the present disclosure, a formulation comprising the compound having a structure according to Formula I, L1-Os-L2, as defined herein, is disclosed. The formulation can include one or more components selected from the group consisting of a solvent, a host, a hole injection material, hole transport material, and an electron transport layer material, disclosed herein.
Combination with Other Materials
The materials described herein as useful for a particular layer in an organic light emitting device may be used in combination with a wide variety of other materials present in the device. For example, emissive dopants disclosed herein may be used in conjunction with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes and other layers that may be present. The materials described or referred to below are non-limiting examples of materials that may be useful in combination with the compounds disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that may be useful in combination.
A hole injecting/transporting material to be used in the present invention is not particularly limited, and any compound may be used as long as the compound is typically used as a hole injecting/transporting material. Examples of the material include, but not limit to: a phthalocyanine or porphryin derivative; an aromatic amine derivative; an indolocarbazole derivative; a polymer containing fluorohydrocarbon; a polymer with conductivity dopants; a conducting polymer, such as PEDOT/PSS; a self-assembly monomer derived from compounds such as phosphonic acid and silane derivatives; a metal oxide derivative, such as MoOx; a p-type semiconducting organic compound, such as 1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and a cross-linkable compounds.
Examples of aromatic amine derivatives used in HIL or HTL include, but not limit to the following general structures:
Each of Ar1 to Ar9 is selected from the group consisting aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; group consisting aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine; and group consisting 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Wherein each Ar is further substituted by a substituent selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
In one aspect, Ar1 to Ar9 is independently selected from the group consisting of:
wherein k is an integer from 1 to 20; X101 to X108 is C (including CH) or N; Z101 is NAr1, O, or S; Ar1 has the same group defined above.
Examples of metal complexes used in HIL or HTL include, but not limit to the following general formula:
wherein Met is a metal, which can have an atomic weight greater than 40; (Y101-Y102) is a bidentate ligand, Y101 and Y102 are independently selected from C, N, O, P, and S; L101 is an ancillary ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal; and k′+k″ is the maximum number of ligands that may be attached to the metal.
In one aspect, (Y101-Y102) is a 2-phenylpyridine derivative. In another aspect, (Y101-Y102) is a carbene ligand. In another aspect, Met is selected from Ir, Pt, Os, and Zn. In a further aspect, the metal complex has a smallest oxidation potential in solution vs. Fc+/Fc couple less than about 0.6 V.
The light emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as light emitting material, and may contain a host material using the metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complexes or organic compounds may be used as long as the triplet energy of the host is larger than that of the dopant. While the Table below categorizes host materials as preferred for devices that emit various colors, any host material may be used with any dopant so long as the triplet criteria is satisfied.
Examples of metal complexes used as host are preferred to have the following general formula:
wherein Met is a metal; (Y103-Y104) is a bidentate ligand, Y103 and Y104 are independently selected from C, N, O, P, and S; L101 is an another ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal; and k′+k″ is the maximum number of ligands that may be attached to the metal.
In one aspect, the metal complexes are:
wherein (O—N) is a bidentate ligand, having metal coordinated to atoms O and N.
In another aspect, Met is selected from Ir and Pt. In a further aspect, (Y103-Y104) is a carbene ligand.
Examples of organic compounds used as host are selected from the group consisting aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; group consisting aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine; and group consisting 2 to 10 cyclic structural units which are groups of the same type or different types selected from the aromatic hydrocarbon cyclic group and the aromatic heterocyclic group and are bonded to each other directly or via at least one of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, chain structural unit and the aliphatic cyclic group. Wherein each group is further substituted by a substituent selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.
In one aspect, host compound contains at least one of the following groups in the molecule:
wherein R101 to R107 is independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. k is an integer from 0 to 20 or 1 to 20; k′″ is an integer from 0 to 20. X101 to X108 is selected from C (including CH) or N. Z101 and Z102 is selected from NR101, O, or S.
A hole blocking layer (HBL) may be used to reduce the number of holes and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED.
In one aspect, compound used in HBL contains the same molecule or the same functional groups used as host described above.
In another aspect, compound used in HBL contains at least one of the following groups in the molecule:
wherein k is an integer from 1 to 20; L101 is an another ligand, k′ is an integer from 1 to 3.
Electron transport layer (ETL) may include a material capable of transporting electrons. Electron transport layer may be intrinsic (undoped), or doped. Doping may be used to enhance conductivity. Examples of the ETL material are not particularly limited, and any metal complexes or organic compounds may be used as long as they are typically used to transport electrons.
In one aspect, compound used in ETL contains at least one of the following groups in the molecule:
wherein R101 is selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is aryl or heteroaryl, it has the similar definition as Ar's mentioned above. Ar1 to Ar3 has the similar definition as Ar's mentioned above. k is an integer from 1 to 20. X101 to X108 is selected from C (including CH) or N.
In another aspect, the metal complexes used in ETL contains, but not limit to the following general formula:
wherein (O—N) or (N—N) is a bidentate ligand, having metal coordinated to atoms O, N or N,N; L101 is another ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal.
In any above-mentioned compounds used in each layer of the OLED device, the hydrogen atoms can be partially or fully deuterated. Thus, any specifically listed substituent, such as, without limitation, methyl, phenyl, pyridyl, etc. encompasses undeuterated, partially deuterated, and fully deuterated versions thereof. Similarly, classes of substituents such as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc. also encompass undeuterated, partially deuterated, and fully deuterated versions thereof.
In addition to and/or in combination with the materials disclosed herein, many hole injection materials, hole transporting materials, host materials, dopant materials, exiton/hole blocking layer materials, electron transporting and electron injecting materials may be used in an OLED. Non-limiting examples of the materials that may be used in an OLED in combination with materials disclosed herein are listed in Table 2 below. Table 2 lists non-limiting classes of materials, non-limiting examples of compounds for each class, and references that disclose the materials.
It is understood that the various embodiments described herein are by way of example only, and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures without deviating from the spirit of the invention. The present invention as claimed may therefore include variations from the particular examples and preferred embodiments described herein, as will be apparent to one of skill in the art. It is understood that various theories as to why the invention works are not intended to be limiting.
