Patent Application
20230145517
The present application claims priority under 35 U.S.C. § 119 to European Patent Application No. 21207769.7, filed Nov. 11, 2021, the entire contents of which are incorporated herein by reference.
The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871336.
One or more embodiments of the present invention relate to a detector for electromagnetic radiation, particularly an X-ray and/or gamma detector, comprising a first, pixelated electrode layer comprising a multitude of electrode pixels, a first layer comprising a multitude of tiles comprising a material absorbing and converting the electromagnetic radiation, wherein at least edges of tiles facing another tile have been cut using pulsed laser cutting, and a second electrode layer, as well as a method of producing such a detector.
For pixelated radiation detectors, particularly X-ray and/or gamma detectors, usually the production of large detector surfaces is necessary. A particular difficulty is the production of large absorber layers as direct conversion layers, particularly comprising or made of perovskite, but also the same or similar problems exist in the production of large absorber layers comprising or made of other direct conversion materials like CdTe, CdZnTe, GaAs, a-Se, HgI2, PbO, Si, TlBr, etc.
A method of producing large detector surfaces is e.g. disclosed in EP 21165773.9, to which is made reference, and which discloses radiation detectors with butted absorber tiles with minimized dead areas. The method disclosed therein is based on tiling of smaller absorber layer parts on a, e.g. pixelated, backplane. Empty areas between the parts then can be filled with a semiconductor and/or a perovskite, thus minimizing or even deleting areas without detector signal between the different parts. Tiling therein has the advantage that not only larger detector areas can be produced, but also that varying detector geometries, e.g. with curvatures, can be produced more easily.
When producing the absorber layer parts, there still exists a further problem in particular production methods thereof. Absorber layers (hereinafter also called layers comprising a material absorbing and converting electromagnetic radiation), particular those comprising perovskite or consisting of perovskite, but also those comprising or consisting of other direct conversion materials, usually are produced by a so-called soft-sintering of powders comprising the absorber material in order to produce layers of absorber material that can be handled independently, particularly as thicker absorber layers are needed for efficient radiation detection. Such independent (also considered free-standing) absorber layers, e.g. perovskite layers, are usually extremely brittle, and handling thereof is usually becoming more complicated the larger the area of the produced absorber layer is. In order to produce detector areas of any size, normally parts of the absorber material, e.g. with varying measurements, are combined. For obtaining spaces between these different parts as small as possible, rectangular edges of the absorber layer parts are preferred, e.g. by tiling together rectangular or square tiles. It is, however, technically difficult to produce such edges with absorber layers having a thickness of several hundred micrometers, as e.g. required for sufficient radiation detection.
During soft-sintering of angular absorber layers furthermore it was found that edge areas with thicknesses of several hundred micrometers can show different compression, e.g. based on pressure differences and/or powder filling differences during production. Due to these differences, different areas in edges may occur that can show different, e.g. also diminished, radiation absorption and thus varying signal in comparison to the center of the absorption layer. Particular at corners these problems, e.g. due to differences in applied pressure, these variations may become significant. In addition, also material loss may occur at edges, resulting e.g. in significant roughness at the edges, making tiling without spaces between more difficult.
A further problem that may occur is when tiles are removed from a pressing tool. At such times it may occur that parts of the powder adhere to edges of the angular forms, and thus parts with frayed edges or even with breakages can only be obtained when removing the layer from the tool.
For easier removal of layers from the pressing tool, better pressure distribution and thus densification usually round pressing tools are applied. The resulting parts cannot be easily tiled due to the geometry thereof, though.
In order to change the geometry of e.g. round layers to angular layers that can be tiled, mechanical processes can be applied. For example, cutting of perovskite layers with a diamond thread is described in Liu et al. https://doi.org/10.1002/adom.201600327. While the method was applied to single crystalline material, application to polycrystalline material resulted in breaking of pieces at edges.
Other methods of forming e.g. perovskite are the targeted growth of crystals on a given structure, as described by Yang et al. https://doi.org/10.1002/smtd.201800110, and applying technologies like lithography, as described by Bar-On et al. https://doi.org/10.1002/admt.201800212, for example. While the former is only applicable to the production of crystals on small surfaces—not being applicable to soft-sintering of powders, the latter usually results in a chemical and/or morphological change of the absorber layer due to a significant amount of energy applied and/or the usage of etching agents and solvents.
The inventors have, thus, recognized a need for an improved method of producing a detector for electromagnetic radiation in which tiling of absorber layers can be carried out easily, and in which improved signal detection is possible.
The inventors found that edges of tiles comprising a material absorbing and converting the electromagnetic radiation can be suitably cut using pulsed laser cutting, thereby minimizing the amount of energy introduced around the material cut at the edge, and thus minimizing change in the chemical composition of the material absorbing and converting the electromagnetic radiation. At the same time, the laser pulses are sufficient to suitably remove the material within the focus of the laser, achieving cutting of layers of such material absorbing and converting the electromagnetic radiation with a thickness of several hundred micrometers and even millimeters, and achieving a vertical cut.
In addition, laser cutting allows realizing any suitable geometry of the tiles, so that these can be adapted to any detector or also pixel sizes of e.g. a backplane. Using a laser, precision of the edge in the area of a few micrometers can be achieved, which is far below the pixel size of a detector the tiles are used in, e.g. of about 50-300 μm, thus minimizing inhomogeneities, i.e. areas with different sensitivities, in the detected signal, e.g. an X-ray image
In a first aspect, one or more embodiments of the present invention relate to a detector for electromagnetic radiation, particularly an X-ray and/or gamma detector, comprising:
Furthermore disclosed is a method of producing a detector for electromagnetic radiation, particularly an X-ray and/or gamma detector, comprising:
Further aspects and embodiments of the present invention are disclosed in the dependent claims and can be taken from the following description, figures and examples, without being limited thereto.
The enclosed drawings should illustrate embodiments of the present invention and convey a further understanding thereof. In connection with the description they serve as explanation of concepts and principles of the present invention. Other embodiments and many of the stated advantages can be derived in relation to the drawings. The elements of the drawings are not necessarily to scale towards each other. Identical, functionally equivalent and acting equal features and components are denoted in the figures of the drawings with the same reference numbers, unless noted otherwise.
In
In contrast, an exemplary detector with reduced space between the absorber tiles is schematically shown in
Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which one or more embodiments of the present invention belong.
Amounts within the present invention are given in wt. %, unless stated otherwise or clear from context.
In the present disclosure, a reference to a conductive material refers to an electrically conductive material, unless clearly stated otherwise.
Before the present invention is described in exemplary detail, it is to be understood that the present invention is not limited to the particular component parts of the process steps of the methods described herein as such methods may vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include singular and/or plural referents unless the context clearly dictates otherwise. For example, the term “a” as used herein can be understood as one single entity or in the meaning of “one or more” entities. It is also to be understood that plural forms include singular and/or plural referents unless the context clearly dictates otherwise. It is moreover to be understood that, in case parameter ranges are given which are delimited by numeric values, the ranges are deemed to include these limitation values.
In a first aspect, an embodiment of the present invention relates to a detector for electromagnetic radiation, particularly an X-ray and/or gamma detector, comprising:
Particularly, the first layer is arranged between the first, pixelated electrode layer and the second electrode layer.
The present detector can particularly detect X-ray and/or gamma radiation, but preferably at least detects X-rays or particularly detects X-rays, i.e. is an X-ray detector according to certain embodiments.
In the detector the first, pixelated electrode layer comprising a multitude of electrode pixels is not particularly restricted. The number of electrode pixels is not particularly restricted but is at least 2. According to certain embodiments, the number of electrode pixels, respectively pixels, per row, is between and including 2 and 10000, e.g. between and including 2 and 1000, e.g. between and including 2 and 100. This leads for e.g. square detectors to a number of electrode pixels of e.g. 2×2 to 10000×10000, e.g. 3000×4000. The first, pixelated electrode layer comprises at least 2 pixels, i.e. 2 or more, e.g. 3, 4, 5, 6, 7, 8, 9, 10, or more. The electrode pixels can be suitably contacted electrically. Neither the pixel size nor the material of the electrode pixels is particularly restricted, and those applied in detectors for electromagnetic radiation can be suitably applied. An electrode pixel can have a pitch of 98 μm of a square electrode pixel, but can also have any other size. The material of the electrode pixel is not particularly restricted and may comprise a conductive metal oxide, a conductive polymer and/or a metal, which serves for detection of e.g. an electron or a hole produced in the first layer.
The first, pixelated electrode layer may comprise a substrate on which the electrode pixels may be suitably arranged. The substrate, which may also be called backplane, is not particularly restricted and may be made of a material like glass, silicon, plastic, etc. For contacting the electrode pixels there may be transistors and/or electric connections for each separate pixel, the transistors being e.g. made of a-Si, IGZO or based CMOS technology, etc. The backplane also may include a lower electrode, passivation layers, e.g. comprising oxides and/or nitride, optionally anchor structures/grids, etc.
In addition, also the second electrode layer is not particularly restricted. It may comprise an electrically conductive material, e.g. a conductive metal oxide, a conductive polymer, and/or a metal. According to certain embodiments, the second electrode layer may be arranged planar. According to certain embodiments, the second electrode layer is at least partially or even totally transparent for the electromagnetic radiation to be detected, e.g. X-ray (wavelength ≥10 μm and <10 nm) and/or gamma radiation (wavelength <10 μm). For example, the second electrode layer may comprise indium tin oxide (ITO), aluminium zinc oxide (aluminium doped zinc oxide, AZO), antimony tin oxide (ATO) and/or fluorine tin oxide (FTO) as electrode material, or consist thereof.
In the detector the respective electrode may be suitably connected as anode or cathode.
According to certain embodiments, a surface layer, e.g. glass and/or an encapsulation, may be arranged on the second electrode layer, opposite to the first layer, for protection, which is not particularly restricted. This can be suitably formed.
Also, the first layer comprising a multitude of tiles comprising a material absorbing and converting the electromagnetic radiation, wherein at least edges of tiles facing another tile have been cut using pulsed laser cutting, is not particularly restricted, as long as at least edges of tiles facing another tile have been cut by pulsed laser cutting. While it is not excluded that only edges of tiles facing another tile are cut by pulsed laser cutting, according to certain embodiments all edges of the tiles have been cut by pulsed laser cutting, this way also enabling a homogeneous signal at the edge of the detector. The first layer may be produced as a free-standing layer, but also may be produced not as a free standing layer, e.g. in contact with an electrode, e.g. an ITO- or FTO-electrode on a suitable substrate, e.g. glass.
According to certain embodiments, the first layer particularly consists only of the tiles and optionally a material filling gaps between tiles.
The tiles comprising a material absorbing and converting the electromagnetic radiation in the first layer are not particularly restricted. They can be of regular, e.g. square or rectangular, shape, but can also have any other shape, or may also be irregular. According to certain embodiments, they are square and/or rectangular, so that they can be arranged regularly and as close as possible so that gaps between them can be minimized or even avoided.
In the present detector, the size of the tiles in the first layer is not particularly restricted. According to certain embodiments, the tiles have a size in the range of 1×1 cm2 to 50×50 cm2, preferably between and including 5×5 cm2 to 50×50 cm2, further preferably between and including 10×10 cm2 to 50×50 cm2. With these sizes a good manufacturing of the tiles is warranted, while at the same time a good conversion in the absorption layer is achieved. Particularly, with such size soft-sintering of the tiles, particularly if they comprise at least a first perovskite, is possible, and they can be easily attached. A smaller size of the tiles also enables using particularly smaller presses and tools for manufacturing thereof.
Furthermore, the thickness of the tiles is not particularly restricted and can be e.g. between and including 10 μm to 50000 μm, preferably between and including 25 to 10000 μm, further preferably between and including 50 μm to 3000 μm, further preferably between and including 70 μm to 2000 μm, even further preferably between and including 100 μm and 1500 μm, e.g. between and including 100 μm and 1000 μm.
According to certain embodiments, the tiles have a size in the range of 1×1 cm2 to 50×50 cm2 and a thickness of between and including 10 μm to 50000 μm.
According to certain embodiments, the number of tiles in the first layer is between and including 2 and 1000, preferably between and including 2 and 100, more preferably between and including 2 and 50, even more preferably between and including 2 and 10.
According to certain embodiments, two adjacent tiles in the first layer have a tilt angle between tiles between and including 0° and 5°, so that gaps between them are further minimized.
In the tiles, the material absorbing and converting the electromagnetic radiation is not particularly restricted, and the tiles may comprise one or more of such materials, or may consist of one or more of such materials. For example, the material absorbing and converting the electromagnetic radiation may comprise a scintillator or even consist of the scintillator, e.g. for detecting gamma radiation, the scintillator e.g. being selected from the list consisting of CsI:Tl—thallium doped cesium iodide, terbium doped gadolinium oxysulfids, barium fluoride (BaF2), bismuth germanate (BGO), beryllium fluoride (BeF3), quantum dots, scintillating perovskite nanocrystals (the perovskite being chosen from those described with regard to the first perovskite), etc. Alternatively or in addition, the material absorbing and converting the electromagnetic radiation is a first semiconductor and/or a first perovskite. According to preferred embodiments, the material absorbing and converting the electromagnetic radiation is at least a first semiconductor and/or a first perovskite, particularly at least a first perovskite, also comprising mixtures of two or more first perovskites, and particularly is a first perovskite.
The first semiconductor is not particularly restricted and may include at least one of mercury(II) iodide (HgI2), lead(II) iodide (PbI2), bismuth triiodide (BiI3), thallium bromide (TlBr), lead(II) oxide (PbO), cadmium telluride (CdTe), cadmium zinc telluride (CdZnTe), amorphous selenium (a-Se), Gallium Arsenide (GaAs), and/or silicon (Si). However also organic-inorganic semiconducting perovskites can be semiconductors and thus can be also considered as first semiconductor, but according to certain embodiments are not contained.
Also, the first perovskite is not particularly restricted and may contain any organic, inorganic and/or organic-inorganic perovskite, as well as mixtures thereof. For example, suitable pervoskites are described in WO 2014045021 A1, which is referred to with regard to perovskites. The perovskite may have an ABX structure, e.g. ABX3 structure, with one or more A cations, one or more B cations, and one or more anions X, particularly chosen from chalcogenides and/or halogenides, particularly halogenides, wherein the A and B cations may be organic and/or inorganic—A being particularly an organic cation chosen from alkyl, aryl, aralkyl, alkylaryl, alkenyl and/or alkinyl ammonium groups (i.e. with one, two, three, or four identical or different residues, including the organic residues and H, in the ammonium group), e.g. with 1 to 60 C atoms, and B being particularly an inorganic cation chosen particularly from cations, particularly divalent cations, of metals like Ca, Sr, Cd, Cu, Ni, Mn, Fe, Co, Pd, Ge, Sn, Pb, and lanthanides like Yb, Gd, Eu, suitable chalcogenides include oxide, sulfide, selenide, telluride, and suitable halogenides include e.g. F—, Cl—, Br—, I—, particularly Cl—, Br—, I—.
Suitable examples of perovskites as first perovskite include e.g. MAPbI3 (CH3NH3PbI3), MAPbBr3 (CH3NH3PbBr3), FAPbI3 (HC(NH2)2PbI3), MAPbICl2 (CH3NH3PbICl2), FAPbBr3 (HC(NH2)2PbBr3), EAPbI3 (CH3CH2NH3PbI3), PAPbI3 (CH3CH2CH2NH3PbI3), BA2PbI4 ((CH3CH2CH2CH2NH3)2PbI4), PMA2PbI4 ((C6H5CH2NH3)2PbI4), PEA2PbI4 ((C6H5CH2CH2NH3)2PbI4), EAPbBr3 (CH3CH2NH3PbBr3), PAPbBr3 (CH3CH2CH2NH3PbBr3); further mixed halogenides thereof; inorganic-organic perovskites with a mixture of A-cations with halogenides X (X=Cl, Br, I), e.g. MAFAPbX3 (MA=CH3NH3, FA=HC(NH2)2), MAGAPbX3 (GA=guanidinium), BAPAPbX3 (BA=CH3CH2CH2CH2NH3, PA=CH3CH2CH2NH3), etc.; organic halogenated mixtures, in which the halogens may be partially substituted by other halogens, e.g. halogenides of formula I3-xClx or Br3-xClx, etc., e.g. MAPbI3-xClx or CH3NH3PbBr3-xClx); organic and/or inorganic perovskites where Pb at least partially or even totally is substituted by Sn, Cu, Ni, Bi, Co, Fe, Mn, Cr, Cd, Ge and/or Yb, and/or mixtures thereof; inorganic perovskites and mixtures thereof, e.g. CsPbX3, wherein X=Cl, Br, and/or I, as well as mixtures thereof (e.g. CsPbBr3, CsPbI3, CsPbCl3), Cs3Bi2X9, wherein X=Cl, Br, and/or I, as well as mixtures thereof, Cs3Sb2X9, wherein X=Cl, Br, and/or I, as well as mixtures thereof, Cs2AgBiX6, wherein X=Cl, Br, and/or I, as well as mixtures thereof, Rb3Bi2X9, wherein X=Cl, Br, and/or I, as well as mixtures thereof, Rb3Sb2X9, wherein X=Cl, Br, and/or I, as well as mixtures thereof, CsSnI3; etc., as well as mixtures of the perovskites.
According to certain embodiments, the tiles in the first layer comprise at least a first semiconductor and/or a first perovskite, preferably at least a first perovskite, as the material absorbing and converting the electromagnetic radiation. Particularly, the edges of the first perovskite can be cut sufficiently using pulsed laser cutting.
In the first layer, at least edges of tiles facing another tile have been cut using pulsed laser cutting. According to certain embodiments, all edges of the tiles in the first layer have been cut using pulsed laser cutting. With the pulsed laser cutting, not only straight edges of the tiles can be achieved according to certain embodiments. According to certain embodiments, the edges of the tiles are cut essentially vertically to the major surfaces of the tiles, i.e. being at an angle to the major surfaces of at least 85°, preferably at least 88°, more preferably at least 89°, even more preferably at least 89.5°. Particularly preferably, the edges are cut at an angle of 90° in relation to the major surfaces of the tiles, i.e. they are vertical. However, it is not excluded that there is a deviation from 90°, e.g. when the detector is to be curved.
According to certain embodiments, the respective edges are cut essentially straight, i.e. show a low surface roughness of only a few micrometers along the cut, e.g. less than 20.0 μm, e.g. less than 10.0 μm, e.g. less than 5.0 μm, e.g. 2.0 μm or less, e.g. 1.5 μm or less, e.g. 1.0 μm or less. It has particularly been observed that the mean particle/crystal size decreases in the cut region in comparison to the bulk region, where no influence of the laser occurs, having e.g. particle sizes of about 2 μm or more in the bulk, and particle sizes of 1 μm or less in the cut region. It is assumed that a recrystallization in the cut region occurs with a smaller crystal size. The measurement of surface roughness is not particularly restricted. Particle sizes and/or surface roughness can be e.g. obtained by optical and/or SEM (scanning electron microscopy) imaging together with image analysis, but also other surface roughness measurements including other optical measurement methods and/or tactile methods are feasible. Compared to other method, the pulsed laser cutting allows a higher accuracy, thus reducing empty spaces, respectively dead zones, between tiles, resulting in improved image quality of the detector.
The pulsed laser cutting particularly improves the straightness of tiles, particularly in the case of angular tiles, e.g. rectangular or square tiles, compared to a state just after production. This is e.g. shown in
Furthermore, also additional problems were observed with the pressed wafers (data not shown). Particular, inhomogeneities were observed at the edges, as well as crumbling of powder. Also, a lower densification of up to 10% was observed at edges, and particularly at corners, which leads to a reduced X-ray signal. While such differences are less pronounced in circular pressed tiles, circular pressed tiles have a disadvantage in that they cannot be placed easily next to each other, leaving huge free spaces between round tiles. As particularly thick tiles, e.g. in X-ray or gamma detectors, are usually only available economically via pressing with good homogeneity, the cutting of the edges thus enables a suitable tool for improved image quality in the final detector.
Upon pulsed laser cutting, straight edges were observed (further details shown in examples), with improved signal and homogeneity. Using pulsed laser cutting, also differences could be observed in edge quality and structure not only compared to the original edges obtained in the pressing tool, but also compared to other artificially produced edges, e.g. produced via breaking off or cutting off, e.g. also with a continuous laser.
If the absorber layer is soft sintered in an angular pressing tool, powder lumps adhere to the tool and tear out. This results in an inhomogeneous edge, as shown in
The pulsed laser-cut edges showed improved porosity as well as no structural changes of the material absorbing and converting the electromagnetic radiation (which can be observed when cutting with a continuous laser due to high-energy input). Surprisingly, such improved structure can be obtained even when cutting through thick layers of tiles with thicknesses in the range of several hundred micrometers to several millimeters, and a vertical cut is obtained with high cut precision and thus high precision of the edge in the range of only a few micrometers, e.g. far below the pixel size in the detector.
Another advantage that is obtainable with pulsed laser cutting of the edges is that the geometry of the sample can be varied widely, as can be seen in the views in
The effect of the different edges obtained by methods of the state of the art and by embodiments of the present invention are shown schematically in
According to certain embodiments, the multitude of tiles are butted. With butted tiles, dead zones between the tiles can be minimized or even avoided, thus leading to an improved signal from the detector. Due to the cut edges, butting of the tiles in the detector of the present invention is improved.
Exemplary different buttings of tiles are shown schematically in
Cutting of different geometries also enables reduction of waste material, as shown schematically in
According to certain embodiments, the detector further comprises at least one interlayer between the first, pixelated electrode and the first layer and/or between the first layer and the second electrode layer.
The interlayer therein is a layer that can function as an electron transport layer (respectively hole blocking layer (HBL)) or as a hole transport layer (respectively electron blocking layer (EBL)). The respective layers can be suitably set according to the charge of the respective electrodes, respectively electrode layers. The materials and thicknesses of any interlayers are not particularly restricted.
An exemplary electron transport layer (HBL) may comprise one or more of the following materials, e.g. with ≥30 wt. %, ≥50 wt. %, or ≥70 wt. %, in relation to the electron transport layer; essentially consist of one of more of these materials (e.g. with ≥90 wt. %, ≥95 wt. %, or ≥99 wt. %, in relation to the electron transport layer; or even consist of at least one of these materials (wherein the following list is not exhaustive and also comprises mixtures as well as isomeric mixtures of the materials, e.g. binary, ternary, quaternary mixtures, etc.):
Fullerene derivatives like C60 PCBM ([6,6]-Phenyl C61 butyric acid methyl ester), C70 PCBM ([6,6]-Phenyl C71 butyric acid methyl ester), Bis-C60 PCBM (Bis-[6,6]-phenyl C61 butyric acid methyl ester), C60 oQDM (o-quinodimethane C60 mono adduct), Bis C60-oQDM (o-quinodimethane C60 bis adduct), ICMA (indene C60 mono adduct), ICBA (indene C60 bis adduct), fullerol (C60(OH)44); and other acceptors, comprising polymeric and small molecules like: dithienoindacene-based compounds like 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC), IT-M (ITIC-M; 3,9-bis(2-methylene-((3-(1,1-dicyanomethylene)-6/7-methyl)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene), IT-DM (ITIC-DM; 3,9-bis(2-methylene-((3-(1,1-dicyanomethylene)-6,7-dimethyl)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene) and IDTBR ((5Z,5′Z)-5,5′-((7,7′-(4,4,9,9-Tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazol-7,4-diyl))bis(methanylylidene))bis(3-ethylthiazolidin-2,4-dione)); perylenediimide-based compounds like TPB (tert-butylprydine, C9H13N), SdiPDI-Se (perylenediimide-derivative modified by insertion of selenophene units in the bay position), NIDCS-HO ((2E,2′E)-3,3′-(2,5-Bis(hexyloxy)-1,4-phenylene)bis(2-(5-(4-(N-(2-ethylhexyl)-1,8-naphthalimid)yl)-thiophen-2-yl)acrylonitrile)); diketopyrrolopyrrole-based compounds like DPP6 (dipeptidylaminopeptidase-like protein 6), 6,6′-(Benzo[c][1,2,5]thiadiazole-4,7-diylbis([2,2′-bithiophen]-5′,5-diyl))bis(2,5-bis(2-ethylhexyl)-3-(thiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrol-1,4-dione) (DTDfBT(DPP)2), 6,6′,6″,6′″-(9,9′-spirobi[fluorene]-2,2′,7,7′-tetrayltetrakis(thiophene-5,2-diyl))tetrakis(2,5-bis(2-ethylhexyl)-3-(5-phenylthiophene-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrol-1,4-dione) (SF(DPPB)4); PFN (poly[(9,9-bis(3′-(N,N-dimethylamino)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]), PFN-OX (Poly[9,9-bis(60-(N,N-diethylamino)propyl)-fluorene-alt-9,9-bis-(3-ethyl(oxetane-3-ethyloxy)-hexyl)-fluorene]), PFO (poly(9,9-di-n-octylfluorenyl-2,7-diyl)), PPDIDTT (poly{[N,N′-bis(2-decyl-tetradecyl)-3,4,9,10-perylenediimide-1,7-diyl]-alt-(dithieno[3,2-b:2′,3′-d]thiophene-2,6-diyl)}), TPBi (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene); metal oxides like TiOx, SnOx, IGZO, etc.
An exemplary hole transport layer (EBL) may comprise one or more of the following materials, e.g. with ≥30 wt. %, ≥50 wt. %, or ≥70 wt. %, in relation to the hole transport layer; essentially consist of one of more of these materials (e.g. with ≥90 wt. %, ≥95 wt. %, or ≥99 wt. %, in relation to the hole transport layer; or even consist of at least one of these materials (wherein the following list is not exhaustive and also comprises mixtures as well as isomeric mixtures of the materials, e.g. binary, ternary, quaternary mixtures and/or blends, etc.): poly(3-hexylthiophene-2,5-diyl) (P3HT), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV), CN-PPV, CN-MEH-PPV, other phthalocyanines, poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT), polyfluorene (PF), poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b′]dithiophene-2,6-diyl]] (PCPDTBT), squaraines (e.g. hydrazone end-capped symmetric squaraine with glycolic functionalization or diazulene squaraine), (PTT) (polythieno[3,4-b]thiophene), poly(5,7-bis(4-decanyl-2-thienyl)-thieno(3,4-b)diathiazole-thiophene-2,5) (PDDTT); diketopyrrolopyrrole-based polymers like poly{2,2′-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5′-diyl-alt-thiophene-2,5-diyl} (PDPP3T), poly[[2,5-bis(2-hexyldecyl-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4 c]pyrrole-1,4-diyl]-alt-[3′,3″-dimethyl-2,2′: 5′,2″-terthiophene]-5,5″-diyl] (PMDPP3T) and the Poly{2,2′-[(2,5-bis(2-hexyldecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)dithiophene]-5,5′-diyl-alt-terthiophene-2,5-diyl} (PDPPST), poly[2,6-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophene-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione] (PBDTT-DPP); dithienosilole-based polymers like poly[(4,4-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5′-diyl] (PSBTBT), 7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl)bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophene]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2), poly[2,7-(9,9-dioctyl-dibenzosilole)-alt-4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole] (PSiFDTBT), benzodithiophene-based polymers like poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl] (PTB7), poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))]) (PBDB-T), poly{2,6′-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophene-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione (PBDTT-DPP), poly[4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PBDTT-FTTE), poly[(4,8-bis-(2-ethylhexyloxy)-benzo(1,2-b:4,5-b′)dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene-)-2-6-diyl)] (PBDTTT-C-F), PolyBenzolhiadiaZol (Thiophene)-stat-BenzoDilhiophene (Thiophene)-8 (PBTZT-stat-BDTT-8) and other polymers and copolymers and small molecules with absorption maximum between 320-800 nm; polytriarylamines and derivatives, poly[[2,5-bis(2-octyldodecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl]-alt2[[2,2′-(2,5-thiophene)bisthieno[3,2-b]thiophene]-5,5′-diyl]] (DPP(P)}, polyaniline (PANI), poly[(4,8-bis-(2-ethylhexyloxy)-benzo(1,2-b:4,5-b′)dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene)-2-6-diyl)] (PBDTTT-C), poly[N29-hepta-decanyl-2,7-carbazole-alt-3,6-bis-(thiophen-5-yl)-2,5-dioctyl-2,5-dihydropyrrolo[3,4-]pyrrole-1,4-dione] (PCBTDPP), poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT), poly[2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-(E)-1,2-di(2,2′-bithiophen-5-yl)ethene] (PDPPDBTE), perfluoro(4-methyl-3,6-dioxaoct-7-en)sulfonylfluoride (PFI), poly(4-styrene sulfonate)-graft-polyaniline (PSS-g-PANI); 2f-butyloctyl-4,6-dibromo-3-fluorothieno[3,4-b]thiophene-2-carboxylate (TT-BO), 3′,4f-dichlorobenzyl-4,6-dibromo-3-fluorothieno-[3,4-b]thiophene-2-carboxylate (TT-DCB), and 2,6-bis(trimethyl-tin)-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene (BDT-EH) copolymer (PTB-DCB21), N2,N2,N2′,N2′,N7,N7,N7′,N7′-octakis(4-methoxyphenyl)-9,9′-spirobi[9H-fluorene]-2,2′,7,7′-tetramine (spiro-OMeTAD), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (TFB), N4,N4f-di(naphthalene-1-yl)-N4,N4′-bis(4-vinylphenyl)biphenyl-4,4′-diamine (VNPB), 1,4-bis(4-sulfonatobutoxy)benzene and thiophene moieties (PhNa-1T)); metal oxides like NiOx, MoOx, etc. . . . .
While in the first layer it is preferred that the tiles are butted, with no gaps between them, it is not excluded that the first layer comprises gaps between the tiles. In such embodiments, it is preferred that the gaps are filled with a material comprising at least a second semiconductor and/or at least a second perovskite.
If gaps are present, it is preferred that the gaps between the tiles are fully filled (as also discussed above), so that no dead zone, i.e. zones not sensitive and thus not contributing to the image, remains. However, it is not excluded that a small amount of the gaps is not totally filled, e.g. if a further layer, e.g. an interlayer, is arranged on top of the first layer. In such a case less than 10 vol. %, preferably less than 5 vol. %, particularly less than 1 vol. % of the gaps may not be filled. If the whole gaps are filled, the thickness of the material in the gaps is then preferably essentially the same as the thickness of the tiles.
According to certain embodiments, the gap size g between the tiles depends on the pixel pitch Pg. According to certain embodiments, the following applies:
Pg/100≤g≤Pg*1000; preferably Pg/10≤g≤Pg*100; more preferably Pg≤g≤Pg*10
According to certain embodiments, the gaps between the tiles have a width of 0.1 pixel pitches to 50 pixel pitches, wherein a pixel pitch has a length of between and including 10 μm and 1000 μm.
According to certain embodiments, gaps between tiles are filled with a material comprising at least a second semiconductor and/or at least a second perovskite, e.g. in liquid form, as paste or as solid. After a recrystallization (when using e.g. liquidized perovskite), solvent removal (e.g. when using a paste), etc., a layer comprising the at least second semiconductor and/or the at least second perovskite remains, that can contribute to the signal in the pixels below.
According to certain embodiments, it is ensured that the material comprising at least a second semiconductor and/or at least a second perovskite completely fills the gaps, e.g. using liquefied perovskite and/or a paste. This is comparable (figuratively) to a case where jointing mortar is applied between tiles, particularly deep into the gaps. The laser cut edges of the tiles therein enable a good filling of the gaps, as uneven surfaces on the tile edges can be minimized or even avoided using pulsed laser cutting. Thus, a signal of filled edges can even further be improved.
The material comprising at least a second semiconductor and/or at least a second perovskite in the gaps is not particularly restricted if a second semiconductor and/or at least a second perovskite is contained. According to certain embodiments, the material comprising at least a second semiconductor and/or at least a second perovskite in the gaps essentially consists of (meaning that at least 95 wt. %, at least 99 wt. % or even 99.9 wt. % of the material are the at least first semiconductor and/or first perovskite) or even consists of the at least second semiconductor and/or second perovskite. According to certain embodiments, the material comprising at least a second semiconductor and/or at least a second perovskite in the gaps only comprises a second semiconductor and/or a second perovskite, although it is not excluded that the second semiconductor and/or second perovskite are present as mixtures of second semiconductors and/or second perovskites. Apart from the second semiconductor and/or second perovskite, further materials like binders may be contained, though, in an amount of up to 30 wt. %, preferably up to 30 wt. %, further preferably up to 10 wt. %, even further preferably up to 5 wt. %, in relation to the material comprising at least a second semiconductor and/or at least a second perovskite.
The second semiconductor may be the same as or different from the first semiconductor, e.g. chosen from the ones described above, and/or the second perovskite may be the same as or different from the first perovskite, e.g. chosen from the ones described above. According to certain embodiments, the second semiconductor is the same as the first semiconductor, and/or the second perovskite is the same as the first perovskite.
As some perovskites are also semiconductors, there is also an overlap between the possible materials of the second semiconductor and the second perovskite. According to certain embodiments, the gaps are filled with a material comprising at least a second perovskite, which is particularly advantageous when the material absorbing and converting the electromagnetic radiation comprises a first perovskite, which may be the same as the second perovskite or may be different.
The second perovskite may particularly be applied as liquefied perovskite and hardened, as paste, or as powder, and/or the second semiconductor may be applied as paste and/or as powder. If the material is applied as paste or as powder, suitable additives may be contained, e.g. at least a solvent and/or at least a binder.
A liquefying of the second perovskite is e.g. possible using methylamine (MA) gas, particularly in the case of methylammonium ions in the second perovskite. The process is e.g. described in EP 20155403.7 or Li, C., S. Pang, H. Xu and G. Cui. Methylamine gas based synthesis and healing process toward upscaling of perovskite solar cells: Progress and perspective. Solar RRL, 1(9), 1700076 (2017), wherein reference is made to both with regard to liquefying perovskites with methylamine gas. Due to the MA gas, the perovskite can be liquefied and subsequently be recrystallized, e.g. with changed morphology, as soon as the MA gas is not anymore in the atmosphere. After removing the methylamine gas, the perovskite can thus be recrystallized in gaps according to certain embodiments of the present method, respectively be present in recrystallized form according to certain embodiments of the detector. Particularly, in such a case it is preferred that the second perovskite comprises an alkyl ammonium cation, wherein the alkyl groups have 1 to 4 C-atoms, particularly a methyl ammonium cation.
In such a case, it also may be possible to fill a precursor, e.g. lead iodide of the perovskite and then crystallize it, as e.g. described in EP 3304611 B1.
For the application of a paste, the at least one second semiconductor and/or the at least one second perovskite may be present in the form of particles, which may be suitably mixed with at least one binder and/or at least one solvent. For this purpose, the particles, e.g. in the form of powder, may be dispersed in a suitable solvent, optionally while adding at least one binder. Suitable pastes for application are e.g. described in US 20120181440 A1 and EP 3376260 A1.
In the paste the size of the particles is not particularly restricted and may be e.g. in a range of between and including 0.01 and 600 μm, i.e. also encompass quantum dots and/or nano crystals, e.g. be in a range of between and including 1 and 300 μm, e.g. as measured by sieve analysis or laser diffraction.
If the paste contains at least one binder, the binder is not particularly restricted, and may e.g. be chosen from suitable polymeric resins, e.g. polyvinyl butyral (PVB) resin, an acryl resin, a phenoxy resin, a polyester resin, a polyvinyl formal resin, a polyamide resin, a polystyrene resin, a polycarbonate resin, a polyvinyl acetate resin, a polyurethane resin, an epoxy resin, a polyimide resin, a polyvinyl alcohol resin, a polyethylene resin, a polyester resin, a polycarbonate resin, and any mixtures thereof. The binder amount may be suitably set, based e.g. on the binder, and may be in a range of equal to or less than 30 wt. %, equal to or less than 20 wt. %, and/or more than 1 wt. %, e.g. more than 2 wt. %, based on the total amount of the paste.
If a solvent is contained in the paste, it is not particularly restricted, and may be suitably chosen, e.g. depending on the binder, e.g. from the list dipropylene glycol monomethyl ether (DPGME), butyl cellosolve (BC), γ-butyrolactone, N-methyl-2-pyrrolidone, N,N-dimethylformamide, butyl cellosolve acetate (BCeA), KOCOSOL, butyl cellosolve (BC), ethyl 3-ethoxypropionate (EEP), and mixtures thereof. The amount of solvent, if contained, may be in a range of 1 wt. % to 60 wt. %, e.g. 2 wt. % to 50 wt. %, e.g. 3 wt. % to 40 wt. %, based on the total mass of the paste. In addition, the paste may further include additives such as a dispersant, an antifoaming agent, and a leveling agent.
In case the material in the gaps comprising the at least one second semiconductor and/or the at least one second perovskite is applied as a powder, it may be just applied as a powder of particles of the at least one second semiconductor and/or the at least one second perovskite, with the particles e.g. having a size in a range of between and including 0.01 and 600 μm, e.g. in a range of between and including 1 and 300 μm, as described above with regard to the paste. In such case the powder may just be filled, but can also be compacted, glued together using a suitable resin, etc.
According to certain embodiments, the material in the gaps is filled as a liquefied perovskite that is recrystallized and/or as a paste comprising the at least one second semiconductor and/or the at least one second perovskite.
If the second perovskite and the first perovskite are used and are the same, the tiles still can be distinguished from the material in the gaps, though, due to the manufacturing process. Differences can be found in the morphology of the respective layer at the location of the tiles and in the gaps, e.g. regarding grain sizes, grain boundaries, density, porosity, etc. Thus, the tiles and material in the gaps can be clearly distinguished, even if the same material is used, e.g. regarding the morphology and/or the inside, which is due to the difference in production thereof. As a consequence, also the electric signal, respectively the sensitivity, may be different when comparing the tiles and the material in the gaps, even if the same chemical material is used, due to difference in morphology, etc.
According to certain embodiments, the detector further comprises a second layer between the first, pixelated electrode layer and the first layer, wherein the second layer is an adhesion promoting layer, preferably wherein the second layer comprises at least a third semiconductor and/or a conductor and/or a third perovskite, optionally the detector for electromagnetic radiation comprising at least one interlayer between the first, pixelated electrode and the second layer and/or between the second layer and the first layer.
The thickness of the second layer is not particularly restricted and may be in a range of between 100 nm and 1000 μm, e.g. between 200 nm and 500 μm, e.g. between 300 nm and 100 μm.
According to certain embodiments, the second layer is an anisotropic conductive film (ACF) or anisotropic conductive paste (ACP), which, may, however, according to certain embodiments, need an additional structured electrode on the respective absorber tile, and/or call for a good alignment between the electrodes on the tile and those in the first, pixelated electrode layer, e.g. on the backplane (substrate).
According to certain embodiments, the second layer comprises at least a third semiconductor and/or a conductor and/or a third perovskite.
According to certain embodiments, the second layer comprises a conductor, which is not particularly restricted, e.g. in the form of bump bonds. These bump bonds are not particularly restricted and may be made e.g. of a suitable metal, e.g. a conductive metal like Cu, Ag, Pb, Sn, In etc., as well as alloys thereof, and/or may be made in any suitable form, e.g. in the form of balls, spheres, semi-spheres, pillars, columns, cubes, etc. According to certain embodiments, the bump bonds may further be in contact with a glue, which can be e.g. introduced by an underfill process, etc., but it is also not excluded that the bump bonds are just surrounded by air, etc.
According to certain embodiments, the second layer comprises or even consists of the third perovskite, which may be the same as the first and/or second perovskite or be different. In such instance the second layer may be produced, respectively applied, as liquefied perovskite, as laid out regarding the second perovskite, and recrystallized, and/or be applied with a paste, and dried. According to certain embodiments, the second layer is made from a recrystallized perovskite, that was liquefied, e.g. with MA gas, as described above.
The third perovskite thus is not particularly restricted and may contain any organic, inorganic and/or organic-inorganic perovskite, as well as mixtures thereof, as defined above with regard to the first perovskite.
According to certain embodiments, the detector for electromagnetic radiation comprises at least one interlayer between the first, pixelated electrode and the second layer and/or between the second layer and the first layer, wherein the respective interlayer can be as described above. According to certain embodiments, no interlayer is present between the first layer and the second layer.
According to certain embodiments, the second layer is a structured layer comprising a structure and a material comprising the third semiconductor and/or the conductor and/or the third perovskite filled at least in the structure and/or surrounding the structure. In such embodiments, the structure is not particularly restricted, and can be in the form of a grid, pillars, etc. The structure therein can serve as an anchor structure, which can increase the bond between the first, pixelated electrode layer and the second layer. According to certain embodiments, the structure is as high as the further material of the second layer, or the further material, e.g. the third semiconductor and/or the conductor and/or the third perovskite, surpasses the structure, e.g. for at least 10 nm, at least 100 nm, or even 1 μm, or even 10 μm, or even 30 μm. The grid can be suitably arranged on e.g. the first, pixelated electrode layer, using e.g. resists, laser cutting, welding, etc., for producing the structure. Suitable structures are e.g. described in EP 20155403.7, to which reference is made with regard to the structures.
In a second aspect, an embodiment of the present invention relates to a method of producing a detector for electromagnetic radiation, particularly an X-ray and/or gamma detector, comprising:
With the present method, particularly the detector for electromagnetic radiation according to an embodiment of the present invention can be produced. Thus, certain embodiments discussed with regard to the present detector for electromagnetic radiation also apply to the present method, and vice versa. According to certain embodiments, the steps are carried out in the order given for the present method. However, some steps may be also carried out at a different time, i.e. out of order, e.g. the steps of preparing a multitude of tiles comprising a material absorbing and converting the electromagnetic radiation, and cutting at least part of edges of the tiles comprising a material absorbing and converting the electromagnetic radiation using pulsed laser cutting, particularly edges that will be facing each other during further production of the detector, may be carried out at an earlier time.
In the present method, the step of providing a first, pixelated electrode layer comprising a multitude of electrode pixels is not particularly restricted, and a first, pixelated electrode layer may be provided, as described above with regard to the present detector.
Also, the step of optionally applying a second layer on the first, pixelated electrode layer, wherein the second layer is an adhesion promoting layer, preferably wherein the second layer comprises at least a third semiconductor and/or a conductor and/or a third perovskite, is not particularly restricted. As described above the second layer can be applied e.g. as liquefied third perovskite and recrystallized, as paste and hardened, etc., and can then have a final thickness in a range of between 100 nm and 1000 μm, e.g. between 200 nm and 500 μm, e.g. between 300 nm and 100 μm.
According to certain embodiments, applying the second layer comprises applying a structure, and filling and/or surrounding a material comprising a third semiconductor and/or a conductor and/or a third perovskite at least in the structure and/or around the structure, which may be as described with regard to the present detector. The applying of the structure is not particularly restricted and can be done using photolithography, welding, laser cutting, atomic layer deposition, etc., e.g. as also described above with regard to the detector. When the structure is applied, it can then be filled and/or surrounded (e.g. when the structure comprises pillars) by the material comprising a third semiconductor and/or a conductor and/or a third perovskite, e.g. by applying liquefied perovskite and recrystallization, applying a paste, etc.
In addition, also the step of preparing a multitude of tiles comprising a material absorbing and converting the electromagnetic radiation is not particularly restricted. To obtain a suitable thickness of the tiles, they can be e.g. prepared by soft sintering, cutting single crystalline material, producing thick layers from paste, evaporating and/or sputtering of the material in thick layers, or aerosol, deposition, but also other methods are not excluded.
The step of cutting at least part of edges of the tiles comprising a material absorbing and converting the electromagnetic radiation using pulsed laser cutting, particularly edges that will be facing each other during further production of the detector, is also not particularly restricted, as long as the cutting is carried out using pulsed laser cutting.
The inventors found that pulsed laser cutting achieves removing material of the tiles, particularly the material absorbing and converting the electromagnetic radiation, particularly inside the focal spot of the laser.
The pulsed laser is not particular restricted, but preferably is a laser providing short laser pulses, e.g. a nano-, pico-, or femtosecond laser. According to certain embodiments, the pulsed laser cutting is carried out with a nano-, pico-, or femtosecond laser, particularly a pico- or femtosecond laser, particularly with pulse durations in the range of 500 picoseconds or less and 1 femtosecond or more, e.g. 100 picoseconds or less and 10 femtoseconds or more, e.g. 20 picoseconds or less and 200 femtoseconds or more. It was especially found that with lasers with very short pulse durations it is possible to cut materials even if the wavelength of the laser is above the bandgap of the material. Particularly with such a laser the amount of energy introduced to the material around the cutting edge can be minimized, thus minimizing any changes to the material of the absorber tiles. However, the laser pulses are sufficient to remove the material slowly but steadily. By adjusting of laser parameters a cut can be performed through thick layers of several hundred micrometers to millimeters. The cut is represented by a vertical cut where the porosity of the material, particularly a perovskite, can be improved.
Cutting by a pulsed laser also can realize any cutting geometry, thus being able to adjust the tiles to different detector surfaces and/or pixel sizes of the backplane, etc. The precision of the cut and thus the precision of the edge can be in the range of a few micrometers, as indicated above, this way avoiding inhomogeneities in the detector image, i.e. areas of different sensitivity, which for an X-ray detector can be around 50-300 μm in the area of edges. The material used in the laser as well as the profile of the laser is not particularly restricted. For example, the laser may have a Gauss profile, but also any other laser profile is suitable. Further, the material of the wavelength, e.g. determining the laser wavelength, may also depend on the material to be cut, particularly the material absorbing and converting the electromagnetic radiation. However, also a laser with a wavelength that is too short may damage the material due to an absorption to strong. According to certain embodiments, the laser has a wavelength of at least 500 nm, preferably at least 700 nm, particularly at least 800 nm, e.g. at least 1000 nm. For example, MAPI may be effectively cut with a laser wavelength of at least 800 nm, e.g. with a laser having a wavelength of 1064 nm. According to certain embodiments, the laser has a pulse repetition frequency between and including 50 Hz and 100 MHz, e.g. between and including 100 Hz and 75 MHz, e.g. between and including 500 Hz and 10 MHz, e.g. between and including 1 kHz and 85 KHz.
According to certain embodiments, the pulsed laser cutting is carried out with a laser having a focal point size of between and including 0.1 to 1000 μm, preferably between and including 1.0 to 100 μm, further preferably between and including 1.0 and 50 μm, and/or with a line number nL of 1 to 1000, preferably 2 to 100, more preferably 5 to 30, and/or a laser peak fluence FO (energy per area of material to be cut) of between and including 0.1 to 100.0 J/cm2, preferably between and including 0.2 to 10.0 J/cm2, further preferably between and including 0.27 to 4.0 J/cm2. Particularly, it was found that a laser peak fluence FO that is too low will not achieve sufficient removal of material, thus making the process too long and expensive, while a too high laser peak fluence may result in material decomposition also around the edge, leading to edges with worse surfaces and/or the formation of pristine precursor material at the edges, e.g. PbI2 and MAI in the case of MAPI.
According to certain embodiments, laser cutting is carried out by scanning across the tiles repeatedly. It was found that particularly good results can be obtained if the scanning is carried out in parallel lines to that a sufficiently deep cut can also be obtained easily for very thick materials. According to certain embodiments, the line number of parallel scan lines nL is 1 to 1000, preferably 2 to 100, more preferably 5 to 30.
Furthermore, also optimal numbers of overlap of laser spots have been found for the focal spot during scanning, wherein a preferred overlap in x-direction (scanning direction) Ωx is between and including 10% and 90%, preferably between and including 30% and 85%, further preferably between and including 50% and 85%, and/or a preferred overlap in y-direction (of parallel lines) Ωy is between and including 5% and 80%, preferably between and including 10% and 60%, further preferably between and including 20% and 50%. Particularly, according to certain embodiments, the overlap in y-direction is preferably smaller, in order to minimize energy input with a homogeneous removal of material.
The number of crossings n over the tiles is not particularly restricted and may depend on the material to be cut, the thickness of the tile, etc. The number may also depend on the material removal rate, which can be e.g. at least 50 nm per pulse, e.g. at least 100 nm per pulse, and/or can be e.g. up to 2.5 μm per laser pulse, and/or can even sum up to a depth of e.g. 5.0 to 15 μm (depending on overlap), e.g. 9.1 μm per scan line, e.g. with an overlap Ωx of 80%, when cutting MAPI. The scan speed of the laser of the laser is not particularly restricted. For example, a suitable scanning speed may be between and including 1 and 5000 mm/s, preferably between and including 10 and 1000 mm/s, further preferably between and including 50 and 400 mm/s.
Furthermore, the step of applying the multitude of tiles comprising a material absorbing and converting the electromagnetic radiation on the first, pixelated electrode layer or on the optional second layer, particularly in a way that edges cut by pulsed laser cutting are facing each other, is not particularly restricted either, and the tiles can be suitably attached, e.g. by pressing, gluing, or also by putting it on a layer below before it is hardened, e.g. the second layer before recrystallization or hardening.
According to certain embodiments, the tiles in the first layer comprise at least a first semiconductor and/or a first perovskite, preferably at least a first perovskite, as the material absorbing and converting the electromagnetic radiation, particularly as described with regard to the present detector.
According to certain embodiments, the tiles have a size in the range of 1×1 cm2 to 50×50 cm2, preferably between and including 5×5 cm2 to 50×50 cm2, further preferably between and including 10×10 cm2 to 50×50 cm2.
According to certain embodiments, the number of tiles in the first layer is between and including 2 and 1000, preferably between and including 2 and 100, more preferably between and including 2 and 50, even more preferably between and including 2 and 10.
According to certain embodiments, two adjacent tiles in the first layer have a tilt angle between tiles between and including 0° and 5°.
Furthermore, the thickness of the tiles is not particularly restricted and can be e.g. between and including 10 μm to 50000 μm, preferably between and including 25 to 10000 μm, further preferably between and including 50 μm to 3000 μm, further preferably between and including 70 μm to 2000 μm, even further preferably between and including 100 μm and 1500 μm, e.g. between and including 100 μm and 1000 μm.
According to certain embodiments, the tiles have a size in the range of 1×1 cm2 to 50×50 cm2 and a thickness of between and including 10 μm to 50000 μm.
According to certain embodiments, the multitude of tiles are butted.
Finally, the step of applying a second electrode layer, on the first layer is not particularly restricted.
According to certain embodiments, a surface layer, e.g. glass and/or an encapsulation, may be applied on the second electrode layer, opposite to the first layer, for protection, which is not particularly restricted.
According to certain embodiments, gaps may be comprised between two adjacent tiles. According to certain embodiments, no gaps may be present between two adjacent tiles. If one or more gap is present, it may be filled with a material comprising at least a second semiconductor and/or at least a second perovskite, particularly as described with regard to the present detector, in the gaps until the gaps are filled, wherein the tiles and the filled gaps may then form the first layer.
According to certain embodiments, gaps that may be present are filled with a liquid material, a paste or a powder comprising at least the second semiconductor and/or at least the second perovskite. The material comprising at least a second semiconductor and/or at least a second perovskite can be in the form of a liquid, e.g. as a solution, liquid semiconductor or liquefied perovskite, paste, or solid—e.g. in the form of a powder, as described above, and be filled in the gaps using a suitable applicator, e.g. a dispensing apparatus. According to certain embodiments, the applicator which e.g. fills a liquid semiconductor and/or liquefied perovskite and/or a solution comprising the at least second semiconductor and/or the at least second perovskite, in the gaps between tiles is a dispensing robot, which optionally can be controlled by an artificial intelligence with automatic detection of the gaps and filling thereof. According to certain embodiments, the material comprising at least a second semiconductor and/or at least a second perovskite, e.g. in the form of a liquid, can also be applied in several steps, e.g. layer by layer, to suitably fill the gaps and/or achieve a desired layer thickness.
According to certain embodiments, the method further comprises applying at least one interlayer between the first, pixelated electrode layer and the optional second layer, and/or between the optional second layer and the first layer, or between the first, pixelated electrode layer and the first layer; and/or between the first layer and the second electrode layer.
An exemplary method according to an embodiment of the present invention is schematically shown in
In the method shown in
The above embodiments can be combined arbitrarily, if appropriate. Further possible embodiments and implementations of the present invention comprise also combinations of features not explicitly mentioned in the foregoing or in the following with regard to the examples of the present invention. Particularly, a person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.
The present invention will now be described in detail with reference to several examples thereof. However, these examples are illustrative and do not limit the scope of the present invention.
A circular sample of a MAPI wafer having a diameter of 15 mm and a height of about 750 μm was produced using a circular pressing tool. A section of the wafer was then cut using pulsed laser cutting, and an image of the cut wafer is shown in
Cross-sectional SEM images of the cut surface can be seen in
A difference of a reference MAPI sample (here pure sample 5.2) and a laser cut sample can be seen in the morphology, as seen in the SEM images shown in
In order to further show the advantage of the present method using pulsed laser cutting, a comparison of a laser-cut sample as in Example 1 was made with a sample in which the edge was manually broken with tweezers.
As seen in the figures, the surface of the broken sample has a higher roughness than the laser cut sample. The cross section shows some deepenings and powder lumps. In the LEI images, the topography can be better seen, underlining the impression: The laser cut sample shows a smooth surface with homogenously arranged grains and a few protruding grains. The image of the reference sample is dominated by a wavy surface.
Embodiments of the present invention relate to the cutting of absorber layers of tiles for the production of detectors using such tiles using pulsed laser cutting. This enables the production of precise edges for the tiles, enabling better and easier production of the detector as well as improved signals for the detectors. Also, the use of smaller pressing tools and presses, and thus easier pressing, is possible, reducing the cost for tile production. The precision of the edges is significantly improved—together with a high quality of the edges with small surface roughness in the range of a few micrometers, and thus a reduction of free areas between tiles is possible, leading to improved image quality when using the detectors. Due to the pulsed laser cutting, also flexible geometries of the tiles can be produced, e.g. adapted to special, e.g. curved, detector surfaces, and at most minimal changes in material characteristics of the absorber layer are observed near the cut edges. In addition, laser cutting is a time-efficient process that does not require the additional and detrimental use of chemicals and can be easily automated, thus being adaptable for industrial production of detectors. The high-precision cutting of the absorber layers in the tiles further does not or only minimally influence the material and absorption characteristics, and particularly detrimental absorption characteristics at uncut edges and corners can be avoided. With cutting, it is thus possible to produce flat surface detectors with high sensitivity and resolution at low cost.
The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections, should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of embodiments. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items. The phrase “at least one of” has the same meaning as “and/or”.
Spatially relative terms, such as “beneath,” “below,” “lower,” “under,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below,” “beneath,” or “under,” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. In addition, when an element is referred to as being “between” two elements, the element may be the only element between the two elements, or one or more other intervening elements may be present.
Spatial and functional relationships between elements (for example, between modules) are described using various terms, including “on,” “connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the disclosure, that relationship encompasses a direct relationship where no other intervening elements are present between the first and second elements, and also an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. In contrast, when an element is referred to as being “directly” connected, engaged, interfaced, or coupled to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between,” versus “directly between,” “adjacent,” versus “directly adjacent,” etc.).
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Also, the term “example” is intended to refer to an example or illustration.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It is noted that some embodiments may be described with reference to acts and symbolic representations of operations (e.g., in the form of flow charts, flow diagrams, data flow diagrams, structure diagrams, block diagrams, etc.) that may be implemented in conjunction with units and/or devices discussed above. Although discussed in a particularly manner, a function or operation specified in a specific block may be performed differently from the flow specified in a flowchart, flow diagram, etc. For example, functions or operations illustrated as being performed serially in two consecutive blocks may actually be performed simultaneously, or in some cases be performed in reverse order. Although the flowcharts describe the operations as sequential processes, many of the operations may be performed in parallel, concurrently or simultaneously. In addition, the order of operations may be re-arranged. The processes may be terminated when their operations are completed, but may also have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, subprograms, etc.
Specific structural and functional details disclosed herein are merely representative for purposes of describing embodiments. The present invention may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21207769.7 | Nov 2021 | WO | international |
