Stretchable x-ray photodetector based on metal-organic complex / polymer semiconductor heterojunction

Abstract

The application discloses a stretchable X-ray photodetector based on a metal organic complex / polymer semiconductor heterojunction and a preparation method thereof, and particularly relates to a preparation method of a metal organic complex / polymer semiconductor heterojunction and a structure of a high-performance stretchable X-ray photodetector. The application uses a metal organic complex with high absorption efficiency and a stretchable polymer semiconductor with high transmission efficiency to prepare an organic heterojunction phototransistor, and realizes a stretchable X-ray detector with high photoconductive gain and low noise. Based on the heterojunction structure, the prepared stretchable X-ray photodetector not only realizes high absorption efficiency, fast response speed and detection of an ultra-low dose X-ray, but also has high stretchability and cyclic stretch performance. In addition, the application has low cost, intrinsic flexibility, attachability and good biocompatibility, and has important significance for developing a next-generation portable X-ray detector and three-dimensional imaging technology.

Description

Technical Field

[0001] This invention belongs to the field of flexible organic photoelectric detection technology, specifically relating to a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction and its fabrication method, particularly to a method for fabricating a metal-organic complex / polymer semiconductor heterojunction and the structure of a high-performance stretchable X-ray photodetector. This invention utilizes a metal-organic complex with high absorption efficiency and a stretchable polymer semiconductor with high transmission efficiency to fabricate a heterojunction organic phototransistor, achieving a stretchable X-ray detector with high photoconductive gain and low noise. Background Technology With the widespread application of ionizing radiation technology, the demand for related radiation detectors is constantly increasing, especially the development of highly flexible, low-cost, and highly sensitive X-ray detectors. Currently reported X-ray detectors are mainly based on inorganic semiconductors or scintillators with high absorption efficiency to generate sufficient photocharge. However, these materials have large volume, high hardness, and stringent fabrication conditions, thus limiting the further development of X-ray detection technology. In recent years, flexible, lightweight, and low-cost organic and organic-inorganic hybrid X-ray detection devices have attracted widespread attention. However, the susceptibility of organic semiconductors, especially polymer semiconductors, to radiation damage is a significant concern. Furthermore, device structures with non- or low-gain energy conversion can no longer meet the requirements of high-sensitivity X-ray detectors. Therefore, developing novel ultra-flexible photosensitive materials and intrinsically flexible electronic devices is crucial for the development of next-generation flexible X-ray detectors.

[0002] Currently, common organic X-ray detectors mainly employ two structures: photodiodes and photoresistors. Due to their low photon absorption and conversion efficiencies, they require relatively thick X-ray photoconductors or scintillators, which limits the mechanical flexibility and spatial resolution of the devices. This problem can be overcome by using organic heterojunction X-ray phototransistors, achieving high photoconductor gain and low noise levels (Gao, Y., Ge, Y., Wang, X., et al. Adv. Mater. 2021,33, 2101717.). However, currently reported organic optoelectronic materials with high X-ray sensitivity for direct detection, including small organic molecules and metal-organic frameworks ((a) Temiño, I., Basiricò, L., Fratelli, I., et al. Nat. Commun. 2020, 11, 2136. (b) Liang, C., Zhang, S., Cheng, L., et al. Angew. Chem. Int. Ed. 2020, 59, 11856-11860.), have rigid structures, making them difficult to widely apply in ultra-flexible X-ray photodetectors. Therefore, developing novel structures and general methods based on organic optoelectronic materials (especially existing, batch-stable small organic molecules and polymer semiconductors) to improve X-ray response is crucial for the development of intrinsically flexible X-ray photodetectors. Currently, there are many unresolved challenges in the design and development of stretchable X-ray photodetectors. For example, photoelectric performance often decreases with increasing stretchability, which greatly limits the application of stretchable photodetectors. Although significant progress has been made in stretchable polymer phototransistors, the poor radiation stiffness of polymers severely restricts their use in high-energy photon detection (Büchele, P., Richter, M., Tedde, SF, et al. Nat. Photonics 2015, 9 (12), 843-848.). Furthermore, high voltages are typically required to separate photogenerated carriers and achieve high photoconductive gain, which limits the widespread application of stretchable X-ray detectors. Therefore, there is an urgent need to develop a reliable, stable, radiation-resistant, and universally applicable high-performance stretchable X-ray detector suitable for various known organic semiconductors. Summary of the Invention

[0003] In view of the shortcomings of the existing research, the purpose of this invention is to provide a strategy for forming a photoconductive / conductive organic heterojunction using a metal-organic complex with high absorption efficiency and a stretchable polymer semiconductor with high transmission efficiency, ultimately realizing a heterojunction-type stretchable X-ray photodetector with high photoconductive gain and low noise.

[0004] The stretchable X-ray photodetector provided by this invention is an organic field-effect transistor based on a metal-organic complex / polymer semiconductor heterojunction.

[0005] The stretchable X-ray photodetector can adopt two structures: bottom gate top contact and bottom gate bottom contact. Specifically, it includes a stretchable substrate, a stretchable insulating layer, a stretchable metal-organic complex / polymer semiconductor heterojunction, and stretchable gate and source / drain electrode layers.

[0006] In the aforementioned stretchable X-ray photodetector, the wavelength range of the X-rays is 1 pm-10 nm.

[0007] In the aforementioned stretchable X-ray photodetector, the stretchable metal-organic complex / polymer semiconductor heterojunction comprises a metal-organic complex photosensitive layer and a stretchable polymer semiconductor layer. The metal-organic complex photosensitive layer can directly absorb and convert a large number of high-energy photons; the stretchable polymer semiconductor layer, as a photogenerated carrier transport layer, can participate in carrier transport while inducing photons.

[0008] The metal-organic complex photosensitive layer can be made of small molecules of metal phthalocyanine or metal porphyrin. The metal phthalocyanine small molecules can be selected from: copper phthalocyanine (CuPc), lead phthalocyanine (PbPc), nickel phthalocyanine (NiPc), zinc phthalocyanine (ZnPc), cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc), and perfluorinated copper phthalocyanine (F). 16 One or more of CuPc, vanadium phthalocyanine oxide (VOPc), and titanium phthalocyanine oxide (TiOPc); The metalloporphyrin small molecule may be selected from one or more of the following: porphyrin iron (PP-Fe), porphyrin cobalt (PP-Co), tetracarboxyphenylporphyrin iron (TCPP-Fe), tetraphenylporphyrin cobalt (TPP-Co), tetraphenylporphyrin manganese (TPP-Mn), tetraphenylporphyrin nickel (TPP-Ni), tetraphenylporphyrin copper (TPP-Cu), and tetraphenylporphyrin zinc (TPP-Zn); The metal-organic complex photosensitive layer is a thin film prepared by vacuum evaporation. The growth quality and thickness of the film can be effectively controlled by adjusting the evaporation rate and evaporation time.

[0009] The thickness of the metal-organic complex photosensitive layer can be 30 nm-1 μm, preferably 100-200 nm.

[0010] The stretchable polymer semiconductor layer is a spatially nano-confined polymer thin film.

[0011] The spatially confined polymer film is a blend of conjugated polymer and elastomer polymer. The spatial confinement can be effectively controlled by changing any one of the following: mass concentration of the mixed solution, blending ratio, film formation rate, substrate temperature, annealing temperature, and annealing time.

[0012] The conjugated polymer can be selected from any one of hole-transporting, electron-transporting, and bipolar polymers. Specifically, the conjugated polymer may be poly(3-hexylthiophene) (P3HT), poly{2,5-bis(2-octyldodecyl)-3,6-di(thiophene-2-yl)dionepyrrole[3,4-c]pyrrole-1,4-dione-alt-thiophene[3,2-b]thiophene} (DPPT-TT), poly{3,6-dithiophene-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thiophenevinylthiophene-2,5-diyl} (PDVT-10), poly{ (4,4,9,9-tetrahexadecyl-indarene[1,2-b:5,6-b']dithiophene-2,7-diyl)-alt-(benzo[c][1,2,5]thiadiazole-4,7-diyl)} (IDT-BT), poly(isoindigotrifluoromethylthiophene vinylthiophene) (IID-CF3TVT), poly(fluorinated isoindigotrifluoromethylthiophene vinylthiophene) (FIID-CF3TVT), poly{[N,N9-bis(2-octyldodecyl)] [-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,59-(2,29-dithiophene)} (N2200), or poly[7-fluoro-N,N'-bis(4-decyltetradecyl)-7'-azaisoindigo-6',6''-thiophene[3,2-b]thiophene-2,5-diyl)-7'''-fluoro-N'',N'''-bis(4-decyltetradecyl)-7''-azaisoindigo-6,6'-([2,2]''-bithiophene]-5,5''-diyl)] (PITTI-BT); The elastomer polymer may be selected from any one of the following: natural rubber (NR), styrene-butadiene rubber (SBR), cis-butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), ethylene propylene rubber (EPR), isoprene rubber (IR), nitrile rubber (NBR), fluororubber (FPM), silicone rubber (SiR), chlorinated polyethylene rubber (CM), acrylate rubber (ACM), polydimethylsiloxane (PDMS) hydrogenated styrene-butadiene block copolymer (SEBS), polyacrylate rubber (ABR), and polyurethane elastomer (PU); The mixed solution of the conjugated polymer and the elastomer polymer is a solution prepared by dissolving the conjugated polymer and the elastomer polymer in a mass ratio of 1-9:9-1 (preferably 3:7) in at least one solvent selected from chlorobenzene, dichlorobenzene, chloroform and xylene.

[0013] Specifically, the mass concentration of the mixed solution can be 10 mg / ml - 30 mg / ml, and the spatially confined polymer film can be prepared by any one of spin coating, rod coating or blade coating.

[0014] The thickness of the stretchable polymer semiconductor layer can be 50-200 nm, preferably 100-150 nm.

[0015] In the above-mentioned stretchable X-ray photodetector, both the stretchable substrate and the stretchable insulating layer are made of elastomeric polymer; The elastomer polymer may be selected from any one of the following: natural rubber (NR), styrene-butadiene rubber (SBR), cis-butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), ethylene propylene rubber (EPR), isoprene rubber (IR), nitrile rubber (NBR), fluororubber (FPM), silicone rubber (SiR), chlorinated polyethylene rubber (CM), acrylate rubber (ACM), polydimethylsiloxane (PDMS) hydrogenated styrene-butadiene block copolymer (SEBS), polyacrylate rubber (ABR), and polyurethane elastomer (PU); The thickness of the stretchable substrate can be 50 µm-2 mm, preferably 200 µm-1 mm; The thickness of the stretchable insulating layer can be 1.2 µm-2.5 µm, preferably 1.5 µm-2 µm.

[0016] In the aforementioned stretchable X-ray photodetector, the stretchable gate electrode and the source and drain electrodes are all made of intrinsically stretchable conductive material; The intrinsically stretchable conductive material may be any one of the following or a composite material: metallic single-walled carbon nanotubes (P1-SWNT, P2-SWNT, P3-SWNT, P5-SWNT, P7-SWNT, P8-SWNT, P9-SWNT), metallic nanowires (silver nanowires (Ag NWs), gold nanowires (AuNWs), copper nanowires (Cu NWs)), liquid metals (gallium indium alloy (EGaIn)), conductive polymers (poly(3,4-ethylenedioxythiophene)-polyvinylbenzenesulfonic acid (PEDOT:PSS)), two-dimensional (2D) conductive materials (graphene); The conductivity of the stretchable gate electrode and the source and drain electrodes can be: 1×10⁻⁶ 5 S·m -1 -1×107 S·m -1 .

[0017] The stretchable X-ray photodetector described above is prepared by a method including the following steps: (1) The stretchable substrate, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, the stretchable gate electrode, and the source and drain electrodes are respectively prepared on a substrate on which the organosiloxane polymer is self-assembled on the surface. The stretchable metal-organic complex / polymer semiconductor heterojunction includes a metal-organic complex photosensitive layer and a stretchable polymer semiconductor layer (a spatially nano-confined polymer thin film). (2) First, the stretchable substrate is transferred off the substrate, and then the stretchable substrate is placed on the stretchable gate electrode; the stretchable gate electrode is transferred to the stretchable substrate, and the air bubbles generated during the bonding process are removed by vacuuming; similarly, the stretchable insulating layer, the stretchable metal-organic complex / polymer heterojunction, and the stretchable source and drain electrodes are transferred to the stretchable substrate to obtain the stretchable X-ray photodetector.

[0018] In step (1) of the above method, the stretchable polymer semiconductor layer can be obtained by coating a mixed solution of conjugated polymer and elastomer polymer onto the substrate on which the organosiloxane polymer is self-assembled on the surface by spin coating, rod coating or blade coating, and then annealing. Specifically, spin coating is used, and the spin coating speed can be 1000-5000 r / min, preferably 2000 r / min; the spin coating time can be 40s-1min, specifically 50s; The annealing temperature can be 100-250°C, preferably 150°C.

[0019] The metal-organic complex photosensitive layer is deposited by vacuum evaporation, and the growth quality and thickness of the thin film can be effectively controlled by adjusting the evaporation rate and evaporation time.

[0020] The thickness of the metal-organic complex photosensitive layer can be 30 nm-1 μm, preferably 100-200 nm; The substrate is any one of silicon wafers, SiO2-Si silicon substrates, silicon carbide (SiC), quartz, glass, PET plastic, polyimide (PI) substrates, sapphire substrates, ceramics, metals, and cemented carbides; The substrate for the self-assembled growth of organosiloxane polymers is prepared by heating the substrate and the organosiloxane polymer under vacuum conditions (gas phase modification) or immersing them in solution (liquid phase modification). Before the self-assembly growth of the siloxane polymer, the substrate is first treated as follows: ultrasonically cleaned with deionized water, acetone and isopropanol for 6-7 min in sequence, dried with nitrogen, and then subjected to ozonolysis (UVO or O3plasma) to obtain a surface hydroxylated substrate. The organosiloxane polymer is any one of polydimethylsiloxane, octadecyltrimethoxysilane, octadecyltrichlorosilane, and phenyltrichlorosilane.

[0021] In the above preparation method, both the stretchable substrate and the stretchable insulating layer are prepared on a substrate on which an organosiloxane polymer is self-assembled and grown, by any one of the following methods: drop coating, spin coating, blade coating, rod coating, dip coating, or roll-to-roll process. The solvent used can be any one of benzene, toluene, xylene, chlorobenzene, ethyl acetate, chloroform, dichloromethane, n-hexane, or cyclohexane.

[0022] Specifically, when the stretchable gate electrode and the source and drain electrodes are made of carbon nanotubes, the carbon nanotube electrodes are all made by spraying or inkjet printing on a substrate on which organosiloxane polymers are self-assembled and grown. The solvent used for the carbon nanotube solution is any one of water, ethanol, isopropanol, chlorobenzene, N-methylpyrrolidone, or a mixture thereof; The concentration of the carbon nanotube solution is 0.1-0.5 mg / ml; The spraying conditions are as follows: substrate temperature is 60-150 °C, spray gun distance from substrate is 5-20 cm, spraying speed is 0.1-3 mL / min, and spraying solution volume is 1-5 mL. In step (2) of the above method, the stretchable substrate is transferred off the substrate with pointed tweezers, and then the stretchable substrate is covered on the stretchable gate electrode by a precise bonding method from one side to the other. The stretchable gate electrode is transferred onto the stretchable substrate by thermal bonding or room temperature bonding. The heat bonding process is carried out in a vacuum drying oven; The conditions for heat bonding are: vacuum degree of 0.1-10 Pascals, temperature of 40-90 °C, and time of 0.1-1 hour.

[0023] The application of the stretchable X-ray photodetector based on the metal-organic complex / polymer semiconductor heterojunction in the fabrication of wearable photodetectors also falls within the scope of protection of this invention.

[0024] The beneficial effects of this invention are as follows: This invention proposes a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction, simultaneously achieving high photoconductor gain and low noise level. The stretchable X-ray photodetector fabricated based on this organic semiconductor heterojunction structure not only achieves high absorption efficiency, fast response speed, and detection of ultra-low dose X-rays, but also exhibits high stretchability and cyclic stretching performance. Furthermore, low cost, good biocompatibility, and intrinsic flexibility are also advantages of this invention, which is of great significance for the development of next-generation X-ray detectors and imaging technologies. Attached Figure Description

[0025] Figure 1 The diagram shows the structure of the stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction provided by the present invention. (a) is the bottom gate top contact structure, and (b) is the bottom gate bottom contact structure.

[0026] Figure 2 This refers to the stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction prepared in Example 1 of the present invention.

[0027] Figure 3 The metal phthalocyanine F-based material prepared for Comparative Example 1 of this invention 16 Electrical performance characterization of a CuPc stretchable X-ray photodetector (a) and photoresponse to different doses of X-rays (b).

[0028] Figure 4 The FIID-CF3TVT:SEBS polymer film (a) and the F-based film prepared for this invention 16 Photoresponse curves of a stretchable X-ray photodetector of CuPc / FIID-CF3TVT:SEBS heterojunction (b) under different doses of X-rays. Figure 5 The photocurrent and photosensitivity of the stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction prepared for embodiments of the present invention under different doses of X-rays.

[0029] Figure 6 Atomic force microscopy images of the upper and lower surfaces of the spatially confined polymer film prepared in Example 1 of this invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0032] This invention proposes a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction and its fabrication method. The stretchable X-ray photodetector can be manufactured using... Figure 1 (a) Bottom grid top contact and Figure 1 The middle (b) structure includes two types of gate-bottom contact structures, comprising a stretchable substrate, a stretchable insulating layer, a stretchable metal-organic complex / polymer semiconductor heterojunction, a stretchable gate electrode, and source and drain electrodes; the stretchable metal-organic complex / polymer semiconductor heterojunction includes a metal-organic complex photosensitive layer and a stretchable polymer semiconductor layer. The metal-organic complex photosensitive layer can directly absorb and convert a large number of high-energy photons. The stretchable polymer semiconductor layer, as a photogenerated carrier transport layer, can participate in carrier transport while inducing photons.

[0033] This invention proposes a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction, achieving both high photoconductor gain and low noise levels. Based on this heterojunction structure, the fabricated stretchable X-ray photodetector not only achieves high absorption efficiency, fast response speed, and detection of ultra-low dose X-rays, but also exhibits high stretchability and cyclic stretching performance. Furthermore, low cost, good biocompatibility, and intrinsic flexibility are also advantages of this invention, making it significant for the development of next-generation X-ray detectors and imaging technologies.

[0034] In the aforementioned heterojunction-type stretchable X-ray photodetector, the stretchable metal-organic complex / polymer semiconductor heterojunction comprises a metal-organic complex photosensitive layer and a stretchable polymer semiconductor layer. The metal-organic complex photosensitive layer is a thin film fabricated by vacuum evaporation, and the film growth quality and thickness can be effectively controlled by adjusting the evaporation rate and time. The stretchable polymer semiconductor layer is a spatially nano-confined polymer film. This spatially nano-confined polymer film is a blend of a conjugated polymer and an elastomer polymer, and effective control of the nano-confinence can be achieved by changing any one of the following methods: the mass concentration of the mixed solution, the blending ratio, the film formation rate, the substrate temperature, the annealing temperature, and the annealing time.

[0035] The metal-organic complex photosensitive layer can be a small phthalocyanine molecule: copper phthalocyanine (CuPc), lead phthalocyanine (PbPc), nickel phthalocyanine (NiPc), zinc phthalocyanine (ZnPc), cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc), and perfluorinated copper phthalocyanine (F).16 CuPc), vanadium phthalocyanine oxide (VOPc), titanium phthalocyanine oxide (TiOPc); metal porphyrin small molecules: any one of porphyrin iron (PP-Fe), porphyrin cobalt (PP-Co), tetracarboxyphenylporphyrin iron (TCPP-Fe), tetraphenylporphyrin cobalt (TPP-Co), tetraphenylporphyrin manganese (TPP-Mn), tetraphenylporphyrin nickel (TPP-Ni), tetraphenylporphyrin copper (TPP-Cu), and tetraphenylporphyrin zinc (TPP-Zn); The conjugated polymer can be selected from any one of hole-transporting, electron-transporting, and bipolar polymer semiconductors; specifically, the conjugated polymer can be poly(3-hexylthiophene) (P3HT), poly{2,5-bis(2-octyldodecyl)-3,6-di(thiophene-2-yl)dionepyrrole[3,4-c]pyrrole-1,4-dione-alt-thiophene[3,2-b]thiophene} (DPPT-TT), poly{3,6-dithiophene-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thiophenevinylthiophene-2,5-diyl} (PDVT-10), poly{ (4,4,9,9-tetrahexadecyl-indarene[1,2-b:5,6-b']dithiophene-2,7-diyl)-alt-(benzo[c][1,2,5]thiadiazole-4,7-diyl)} (IDT-BT), poly(isoindigotrifluoromethylthiophene vinylthiophene) (IID-CF3TVT), poly(fluorinated isoindigotrifluoromethylthiophene vinylthiophene) (FIID-CF3TVT), poly{[N,N9-bis(2-octyldodecyl)] [-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,59-(2,29-dithiophene)} (N2200), or poly[7-fluoro-N,N'-bis(4-decyltetradecyl)-7'-azaisoindigo-6',6''-thiophene[3,2-b]thiophene-2,5-diyl)-7'''-fluoro-N'',N'''-bis(4-decyltetradecyl)-7''-azaisoindigo-6,6'-([2,2]''-bithiophene]-5,5''-diyl)] (PITTI-BT); The synthetic routes of polymers IID-CF3TVT and FIID-CF3TVT are based on the patent (Chinese Patent 202010098740.9). The elastomer polymer may be selected from any one of the following: natural rubber (NR), styrene-butadiene rubber (SBR), cis-butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), ethylene propylene rubber (EPR), isoprene rubber (IR), nitrile rubber (NBR), fluororubber (FPM), silicone rubber (SiR), chlorinated polyethylene rubber (CM), acrylate rubber (ACM), polydimethylsiloxane (PDMS) hydrogenated styrene-butadiene block copolymer (SEBS), polyacrylate rubber (ABR), and polyurethane elastomer (PU); The mixed solution of the conjugated polymer and the elastomer polymer is prepared by dissolving the conjugated polymer and the elastomer polymer in a mass ratio of 1-9:9-1 (preferably 3:7) in at least one solvent selected from chlorobenzene, dichlorobenzene, chloroform, and xylene. Specifically, the mass concentration of the mixed solution can be 10 mg / ml - 30 mg / ml, and a spatially confined polymer film can be prepared by any one of spin coating, rod coating, or blade coating. The thickness of the metal-organic complex photosensitive layer can be 30 nm-1 μm, preferably 100-200 nm; The thickness of the stretchable polymer semiconductor layer is 50-200 nm, preferably 100-150 nm; The thickness of the stretchable substrate is 50 µm - 2 mm, preferably 200 µm - 1 mm; The thickness of the stretchable insulating layer is 1.2 µm - 2.5 µm, preferably 1.5 µm - 2 µm.

[0036] The preparation of stretchable metal-organic complex / polymer semiconductor heterojunctions and their application in organic X-ray photodetectors fall within the scope of this invention. This invention provides a stretchable X-ray photodetector based on a metal-organic complex / polymer heterojunction. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the technical solutions in the embodiments of this invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described examples are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] The current-time curves of a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction were measured under both no-X-ray and different doses of X-ray irradiation, and the differences between these conditions were compared. The calculations were performed using the following formula: Photocurrent = Transistor current under illumination - Transistor current under no-light conditions Photosensitivity = (Current of transistor under X-ray illumination - Current of transistor under no X-ray illumination) / (X-ray dose × Irradiation volume) The method for preparing the stretchable X-ray photodetector based on the metal-organic complex / polymer semiconductor heterojunction includes the following steps: 1) The silicon wafer is ultrasonically cleaned sequentially with deionized water, acetone and isopropanol for 6-7 minutes. The solvent on the substrate is removed by purging with high-purity nitrogen. Then the substrate is subjected to ozonolysis (UVO or O3plasma) to obtain a surface hydroxylated substrate. 2) An organosiloxane polymer modification layer is prepared on the substrate of (1) using a gas-phase modification method or a liquid-phase modification method. The gas-phase modification conditions for octadecyltrichlorosilane (OTS) are as follows: a small amount of OTS is applied to the substrate after oxygen plasma cleaning, and then it is placed in a vacuum oven with a vacuum degree of 0.01 Pa. After heating it to 120 °C and maintaining it for 3 h, it is naturally cooled to room temperature to complete the modification process. 3) On a substrate with a self-assembled organosiloxane surface, the stretchable substrate and the stretchable insulating layer are prepared by drop coating, spin coating, blade coating, rod coating, dip coating, or roll-to-roll process; the stretchable gate electrode and source and drain electrodes are prepared by spray coating or inkjet printing; the stretchable polymer semiconductor layer is prepared by spin coating, blade coating, or rod coating, and a metal-organic complex is deposited by vacuum evaporation to obtain a stretchable metal-organic complex / polymer semiconductor heterojunction; 4) The stretchable substrate is transferred from the substrate with the self-assembled molecular layer, and then the stretchable substrate is gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode is then transferred to the stretchable substrate using thermal bonding or room temperature bonding, and a vacuum is applied to remove air bubbles generated at the interface during the bonding process. Subsequently, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes are transferred to the stretchable substrate using the same method to obtain a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction.

[0038] Example 1 This embodiment is based on F 16 A stretchable X-ray photodetector with a bottom-gate top-contact structure was fabricated using a CuPc / FIID-CF3TVT:SEBS heterojunction according to the following steps.

[0039] 1) The silicon wafer is ultrasonically cleaned sequentially with deionized water, acetone and isopropanol for 6-7 minutes. The solvent on the substrate is removed by purging with high-purity nitrogen. Then the substrate is subjected to ozonolysis (UVO) treatment to obtain a substrate with surface hydroxylation treatment. 2) An organosiloxane polymer modification layer was prepared on the substrate of (1) by a gas phase method. The gas phase modification conditions of octadecyltrichlorosilane (OTS) were as follows: a small amount of OTS was coated on the substrate after oxygen plasma cleaning, and then it was placed in a vacuum oven with a vacuum degree of 0.01 Pa. The substrate was then heated to 120 °C and maintained for 3 h, and then naturally cooled to room temperature to complete the modification process. 3) Place the substrate with the self-assembled organosiloxane on a hot stage, slowly draw 1 ml of SEBS-H1221 toluene solution (concentration of 200 mg / mL) with a 1 mL syringe and uniformly drop it onto the silicon wafer with the self-assembled molecular layer. Then keep it at 50 °C for 4 hours and then at 90 °C for 1 hour to obtain a stretchable substrate with a thickness of 1 mm.

[0040] 4) Place the silicon wafer with the self-assembled molecular layer on a hot stage at 80 °C for 5 minutes, transfer 2 mL of carbon nanotube P3-SWNT isopropanol solution (0.2 mg / mL) into the volume chamber of the spray gun, and then spray it uniformly onto the silicon wafer with the self-assembled molecular layer at a rate of 0.2 mL / min (wherein, the distance between the spray gun nozzle and the silicon wafer is 8 cm) to obtain the stretchable gate electrode.

[0041] 5) Place the silicon wafer with the self-assembled molecular layer at the center of the spin coater rotor. Use a 1 mL pipette to draw 200 mL of SEBS-H1052 cyclohexane solution (concentration 70 mg / mL) and then evenly drop it onto the silicon wafer with the self-assembled molecular layer. Start the spin coater and maintain a speed of 1000 rpm for 1 minute. Finally, remove the silicon wafer and anneal it on a hot plate at 80°C for 1 hour to obtain a stretchable insulating layer with a thickness of 2 µm.

[0042] 6) Place the silicon wafer with the self-assembled molecular layer at the center of the spin coater rotor. Add 20 µL of FIID-CF3TVT:SEBS xylene solution (wherein the mass ratio of the two polymers is 3:7 and the concentration is 10 mg / ml) onto the silicon wafer using a 50 µL pipette. Then spin coat at 2000 rpm for 1 minute. Finally, place the silicon wafer on a hot plate and anneal at 220 °C for 10 minutes to obtain a stretchable polymer semiconductor layer with a thickness of 100 nm. Figure 6 (Atomic force microscopy images of the upper and lower surfaces of the prepared spatially confined polymer film); then F was deposited by vacuum evaporation. 16 CuPc small molecular layers are thus obtained to obtain stretchable metal-organic complex / polymer semiconductor heterojunctions. 7) Place the silicon wafer with the self-assembled molecular layer on a magnet, and then place a mask on the silicon wafer to tightly adhere the mask to the silicon wafer with the self-assembled molecular layer. Gently place the magnet and silicon wafer on a hot stage at 120 °C for 15 minutes. Then, use a 5 mL pipette to draw 2 mL of an isopropanol solution of carbon nanotube P3-SWNT (concentration of 0.15 mg / mL) and spray it uniformly onto the silicon wafer with the self-assembled molecular layer at a rate of 0.2 mL / min (wherein, the distance between the nozzle of the spray gun and the silicon wafer is 10 cm). This will give you a silicon wafer with patterned carbon nanotube source and drain electrodes.

[0043] 8) The stretchable substrate is transferred from the substrate with the self-assembled molecular layer, and then the stretchable substrate is gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode is then transferred to the stretchable substrate via thermal bonding. The substrate is placed in a vacuum drying oven with a vacuum level of 0.1 Pascals at 60°C for 20 minutes to remove air bubbles generated at the interface during bonding. After cooling to room temperature, the substrate is removed. Subsequently, the same method is used to transfer the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes to the stretchable substrate, thus obtaining a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction.

[0044] Figure 2 This invention relates to a stretchable X-ray photodetector fabricated based on a metal-organic complex / polymer semiconductor heterojunction.

[0045] Example 2 This embodiment is based on F 16 A stretchable X-ray photodetector with a bottom-gate top-contact structure was fabricated using a CuPc / N2200:SEBS heterojunction according to the following steps.

[0046] Following the exact same preparation method as in Example 1, except that the polymer FIID-CF3TVT:SEBS xylene solution was replaced with an N2200:SEBS chlorobenzene solution, the stretchable substrate was transferred from the substrate with the self-assembled molecular layer and then gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode was then transferred to the stretchable substrate using a thermal bonding method. Subsequently, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes were transferred to the stretchable substrate using the same method to obtain a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction.

[0047] Example 3 This embodiment is based on F 16 A stretchable X-ray photodetector with a bottom-gate top-contact structure was fabricated using a CuPc / DPP-TT:SEBS heterojunction according to the following steps.

[0048] Following the exact same preparation method as in Example 1, except that the polymer FIID-CF3TVT:SEBS xylene solution was replaced with a DPP-TT:SEBS chlorobenzene solution. The stretchable substrate was transferred from the substrate with the self-assembled molecular layer, and then gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode was then transferred to the stretchable substrate using a thermal bonding method. Subsequently, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes were transferred to the stretchable substrate using the same method, thus obtaining a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction.

[0049] Example 4 This embodiment is based on a CuPc / FIID-CF3TVT:SEBS heterojunction, and a stretchable X-ray photodetector with a bottom gate and top contact structure is fabricated according to the following steps.

[0050] Following the exact same preparation method as in Example 1, only the phthalocyanine small molecule F was used. 16 CuPc is replaced with CuPc molecules. The stretchable substrate is transferred from the substrate with the self-assembled molecular layer, and then the stretchable substrate is gently attached to the stretchable gate electrode from one side to the other. The stretchable gate electrode is then transferred to the stretchable substrate using a thermal bonding method. Subsequently, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes are transferred to the stretchable substrate using the same method, thus obtaining a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction.

[0051] Example 5 This embodiment is based on a PP-Fe / FIID-CF3TVT:SEBS heterojunction, and a stretchable X-ray photodetector with a bottom-gate top-contact structure is fabricated according to the following steps.

[0052] Following the exact same preparation method as in Example 1, only the phthalocyanine small molecule F was used. 16CuPc is replaced with porphyrin-based small molecule PP-Fe. The stretchable substrate is transferred from the substrate with the self-assembled molecular layer, and then the stretchable substrate is gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode is then transferred to the stretchable substrate using a thermal bonding method. Subsequently, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes are transferred to the stretchable substrate using the same method, thus obtaining a stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction.

[0053] Comparative Example 1 This embodiment is based on F 16 A stretchable X-ray photodetector with a bottom grid top contact structure was fabricated according to the following steps.

[0054] The preparation method was exactly the same as in Example 1, except that the step of preparing the polymer FIID-CF3TVT:SEBS film was omitted. The stretchable substrate was transferred from the substrate with the self-assembled molecular layer, and then the stretchable substrate was gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode was then transferred to the stretchable substrate by thermal bonding. Subsequently, the stretchable insulating layer and the FIID-CF3TVT:SEBS film were prepared using the same method. 16 By transferring the CuPc thin film and the stretchable source and drain electrodes onto the stretchable substrate, a CuPc-based material can be fabricated. 16 Stretchable X-ray photodetector for CuPc thin films.

[0055] Figure 3 (a) is based on F 16 Electrical performance characterization of CuPc thin film X-ray photodetector; (b) for comparative example 1 of this invention based on F 16 The light response of an X-ray photodetector made of CuPc thin film to different doses of X-rays. Figure 3 (a) and Figure 3 Analysis of (b) shows that F 16 CuPc phthalocyanine molecules have high X-ray absorption and conversion efficiency, thus exhibiting highly sensitive X-ray light response.

[0056] Comparative Example 2 This embodiment uses a spatially nanoconfined FIID-CF3TVT:SEBS polymer film to prepare a stretchable X-ray photodetector with a bottom grid and top contact structure according to the following steps.

[0057] Following the exact same preparation method as in Example 1, only the preparation of F was removed. 16The steps for fabricating a CuPc phthalocyanine molecular thin film are as follows: The stretchable substrate is transferred from a substrate with a self-assembled molecular layer, and then the stretchable substrate is gently bonded to the stretchable gate electrode from one side to the other. The stretchable gate electrode is then transferred to the stretchable substrate via thermal bonding. Subsequently, the stretchable insulating layer, the stretchable polymer semiconductor layer, and the stretchable source and drain electrodes are transferred to the stretchable substrate using the same method to obtain a polymer semiconductor-based stretchable X-ray photodetector.

[0058] Figure 4 (a) shows the photoresponse of the X-ray photodetector based on FIID-CF3TVT:SEBS polymer film prepared in Comparative Example 2 of the present invention to different doses of X-rays; (b) shows the photoresponse of the X-ray photodetector based on FIID-CF3TVT:SEBS polymer film prepared in Example 1 of the present invention. 16 The X-ray photodetector based on a CuPc / FIID-CF3TVT:SEBS heterojunction exhibits photoresponse to different doses of X-rays. Figure 4 (a) and Figure 4 Analysis in (b) shows that the heterojunction-type stretchable X-ray detector prepared in Example 1 has high light response and low noise level, and can realize ultra-low dose X-ray detection.

[0059] Figure 5 The photocurrent and photosensitivity of the stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction prepared in Example 1 of this invention under different doses of X-rays.

[0060] Depend on Figure 4 and Figure 5 Analysis shows that the stretchable X-ray photodetector based on metal-organic complex / polymer semiconductor heterojunction exhibits high sensitivity (~10). 9 μC Gy cm -3 ), fast response (~40ms) and low dose (49.69 nGy s), -1 The X-ray detection capability is enhanced. More importantly, the stretchable X-ray photodetector of the metal-organic complex / polymer semiconductor heterojunction prepared in Example 1 exhibits high strain resistance. Therefore, the stretchable X-ray photodetector based on nano-confined polymer thin films prepared in the examples can fully meet the requirements of practical applications.

[0061] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A stretchable X-ray photodetector based on a metal-organic complex / polymer semiconductor heterojunction, characterized in that: The stretchable X-ray photodetector is an organic field-effect transistor based on a metal-organic complex / polymer semiconductor heterojunction. It adopts a bottom-gate top contact or bottom-gate bottom contact structure, including a stretchable substrate, a stretchable insulating layer, a stretchable metal-organic complex / polymer semiconductor heterojunction, and a stretchable gate electrode and stretchable source and drain electrode layers; The stretchable metal-organic complex / polymer semiconductor heterojunction includes a metal-organic complex photosensitive layer and a stretchable polymer semiconductor layer. The metal-organic complex photosensitive layer is made of small molecules of metal phthalocyanine or metal porphyrin; The stretchable polymer semiconductor layer is a spatially nano-confined polymer thin film; The spatially confined polymer film is a blend of a conjugated polymer and an elastomeric polymer. The conjugated polymer is selected from any one of hole-transporting, electron-transporting, and bipolar polymers. The conjugated polymers are poly(3-hexylthiophene)P3HT, poly{2,5-bis(2-octyldodecyl)-3,6-di(thiophene-2-yl)dionepyrrole[3,4-c]pyrrole-1,4-dione-alt-thiophene[3,2-b]thiophene}DPPT-TT, poly{3,6-dithiophene-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thiophenevinylthiophene-2,5-diyl}PDVT-10, and poly{(4,4,9,9-tetrahexadecyl- [1,2-b:5,6-b']dithiophene-2,7-diyl)-alt-(benzo[c][1,2,5]thiadiazole-4,7-diyl)}IDT-BT, poly(isoindigotrifluoromethylthiophene vinylthiophene)IID-CF3TVT, poly(fluorinated isoindigotrifluoromethylthiophene vinylthiophene)FIID-CF3TVT, poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} Any one of N2200 and poly[7-fluoro-N,N'-bis(4-decyltetradecyl)-7'-azaisoindigo-6',6''-(thieno[3,2-b]thiophene-2,5-diyl)-7'''-fluoro-N'',N'''-bis(4-decyltetradecyl)-7''-azaisoindigo-6,6'-([2,2''-bithiophene]-5,5''-diyl)]PITTI-BT.

2. The stretchable X-ray photodetector according to claim 1, characterized in that: X-rays have a wavelength range of 1 pm to 10 nm.

3. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The metal-organic complex photosensitive layer is a thin film prepared by vacuum evaporation.

4. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The metal phthalocyanine small molecules are selected from: copper phthalocyanine CuPc, lead phthalocyanine PbPc, nickel phthalocyanine NiPc, zinc phthalocyanine ZnPc, cobalt phthalocyanine CoPc, iron phthalocyanine FePc, and copper phthalocyanine F. 16 One or more of CuPc, vanadium phthalocyanine oxide (VOPc), and titanium phthalocyanine oxide (TiOPc).

5. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The metalloporphyrin small molecules are selected from one or more of the following: porphyrin iron PP-Fe, porphyrin cobalt PP-Co, tetracarboxyphenylporphyrin iron TCPP-Fe, tetraphenylporphyrin cobalt TPP-Co, tetraphenylporphyrin manganese TPP-Mn, tetraphenylporphyrin nickel TPP-Ni, tetraphenylporphyrin copper TPP-Cu, and tetraphenylporphyrin zinc TPP-Zn.

6. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The thickness of the metal-organic complex photosensitive layer is 30 nm-1 μm.

7. The stretchable X-ray photodetector according to claim 6, characterized in that: The thickness of the metal-organic complex photosensitive layer is 100-200 nm.

8. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The elastomer polymer is selected from any one of the following: natural rubber (NR), styrene-butadiene rubber (SBR), cis-butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), ethylene propylene rubber (EPR), isoprene rubber (IR), nitrile rubber (NBR), fluororubber (FPM), silicone rubber (SiR), chlorinated polyethylene rubber (CM), acrylate rubber (ACM), hydrogenated styrene-butadiene block copolymer (SEBS), acrylate-butadiene rubber (ABR), and polyurethane elastomer (PU).

9. The stretchable X-ray photodetector according to claim 8, characterized in that: The elastomer polymer is selected from polydimethylsiloxane (PDMS).

10. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The thickness of the stretchable polymer semiconductor layer is 50-200 nm.

11. The stretchable X-ray photodetector according to claim 10, characterized in that: The thickness of the stretchable polymer semiconductor layer is 100-150 nm.

12. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The blend film of the conjugated polymer and the elastomer polymer is prepared from their mixed solution; The mixed solution of the conjugated polymer and the elastomer polymer is a solution prepared by dissolving the conjugated polymer and the elastomer polymer in a mass ratio of 1-9:9-1 in at least one solvent selected from chlorobenzene, dichlorobenzene, chloroform and xylene. The mass concentration of the mixed solution of the conjugated polymer and the elastomer polymer is 10 mg / ml to 30 mg / ml.

13. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: Both the stretchable substrate and the stretchable insulating layer are made of any one of the following elastomeric polymers: unsaturated rubber, saturated rubber, and thermoplastic elastomers.

14. The stretchable X-ray photodetector according to claim 13, characterized in that: The thickness of the stretchable substrate is 50 µm-2 mm.

15. The stretchable X-ray photodetector according to claim 14, characterized in that: The thickness of the stretchable substrate is 200 µm-1 mm.

16. The stretchable X-ray photodetector according to claim 13, characterized in that: The thickness of the stretchable insulating layer is 1.2 µm-2.5 µm.

17. The stretchable X-ray photodetector according to claim 16, characterized in that: The thickness of the stretchable insulating layer is 1.5 µm-2 µm.

18. The stretchable X-ray photodetector according to claim 1 or 2, characterized in that: The stretchable gate electrode and the stretchable source and drain electrodes are all composed of intrinsically stretchable conductive materials.

19. The stretchable X-ray photodetector according to claim 18, characterized in that: The intrinsically stretchable conductive material is any one of metallic single-walled carbon nanotubes, metal nanowires, liquid metals, conductive polymers, two-dimensional conductive materials, or a composite material thereof.

20. The stretchable X-ray photodetector according to claim 18, characterized in that: The conductivity of the stretchable gate electrode and the stretchable source and drain electrodes is 1×10⁻⁶. 5 S·m -1 -1×10 7 S·m -1 .

21. A method for preparing a stretchable X-ray photodetector according to any one of claims 1-20, comprising the following steps: The stretchable substrate, the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, the stretchable gate electrode, and the stretchable source and drain electrodes are respectively prepared on a substrate on which organosiloxane polymers are grown by surface self-assembly. in, The stretchable metal-organic complex / polymer semiconductor heterojunction includes a metal-organic complex photosensitive layer and a stretchable polymer semiconductor layer, wherein the stretchable polymer semiconductor is a spatially nano-confined polymer thin film. First, the stretchable substrate is transferred off the substrate, and then the stretchable substrate is placed on the stretchable gate electrode to transfer the stretchable gate electrode onto the stretchable substrate. Vacuum is then drawn to remove air bubbles generated during the bonding process. The stretchable X-ray photodetector can be fabricated by transferring the stretchable insulating layer, the stretchable metal-organic complex / polymer semiconductor heterojunction, and the stretchable source and drain electrodes onto the stretchable substrate.

22. The method according to claim 21, characterized in that: The stretchable metal-organic complex / polymer semiconductor heterojunction is prepared by coating a mixed solution of conjugated polymer and elastomer polymer onto a substrate on which organosiloxane polymer is self-assembled, using spin coating, rod coating, or blade coating methods, followed by annealing to prepare a stretchable polymer semiconductor layer. Subsequently, a small molecule thin film of a metal-organic complex was prepared by vacuum deposition.

23. The application of the stretchable X-ray photodetector according to any one of claims 1-20 in a wearable photodetector.

Images