Stretchable x-ray photodetector based on polymer semiconductor thin film and method of making the same

Abstract

The application discloses a stretchable organic X-ray photodetector based on a polymer semiconductor thin film, and particularly relates to a method for regulating and controlling self-assembly of a polymer blend thin film, and a high-sensitivity direct stretchable X-ray photodetector based on a polymer. The application proposes a strategy of eccentric spin coating for inducing self-assembly of a blend film, and a stretchable polymer thin film with nano confinement is prepared, and effective control of a nano morphology of a photoelectric material is realized. Based on the nano confinement thin film, the prepared stretchable X-ray photodetector not only has the X-ray detection capability of high sensitivity, fast response and low dose, but also has high light transmittance, high stretchability and fatigue resistance. Meanwhile, the application has unique advantages of low cost, large area and high flexibility, can be directly attached to a complex surface or structure of a living body, and thus high-definition detection results can be obtained in a lower radiation dose and a very short time, which has important significance in the fields of safety inspection and precision medical treatment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of flexible photoelectric detection, and relates to a stretchable X-ray photodetector based on a polymer semiconductor thin film and a preparation method thereof, in particular to a method for preparing a self-assembled nano-confined semiconductor blend film by eccentric spin coating, and a high-sensitivity stretchable X-ray photodetector based on a polymer. The present application realizes the regulation and control of nano-confined blending polymers by using the eccentric spin coating method, so that the polymer thin film under nano confinement has unique X-ray light response characteristics. BACKGROUND

[0002] X-ray detection and imaging technology is currently widely used in military equipment, medical diagnosis, non-destructive testing of engineering machinery and other fields. However, high-energy X-ray photons are easy to damage the structure and performance of organic materials. The high-energy photodetectors currently realized are mainly based on inorganic crystal materials (such as amorphous silicon, selenium, diamond), which have the disadvantages of large volume, bulkiness, high power consumption, inflexibility, etc., greatly limiting the application of X-ray detection technology. Although these materials exhibit excellent detection performance, there are still some substantial limitations. In particular, in realizing large-area pixel detection matrix, complex human body deformation (such as electronic skin), and biological radiation dose measurement.

[0003] In recent years, with the development of organic semiconductor materials, flexible, lightweight and low-cost organic or hybrid detection devices have gradually matured. The common organic X-ray detector is indirect detection, mainly using photodiode (OPD) and photosensitive resistor two structures. However, the organic scintillator material, doped scintillator, fluorescent molecule and inorganic high atomic number nanoparticles used in indirect detection have complex material synthesis process and limited luminescent efficiency, so it is difficult to realize the requirements of large area and high performance detection device. The high X-ray sensitive photoelectric materials used for direct detection such as molecular crystal TIPS-pentacene, 4HCB and DNN((a) Lai, S., Cosseddu, P., Basiricò, L., et al. Adv. Electron. Mater. 2017, 3(8), 1600409. (b) Fraboni, B., Ciavatti, A., Basiricò, L., F, et al. Faraday Discuss. 2014, 174(0), 219-234.) can directly convert high-energy radiation into electrical signals, with higher sensitivity and faster response speed, but such small molecules are difficult to be applied to the stretchable photoelectric field due to their rigid structure. For flexible conjugated semiconductor polymers with lower mobility and poor radiation hardness, they are greatly limited in radiation detection (Büchele, P., Richter, M., Tedde, S.F., et al. Nat. Photonics 2015, 9(12), 843-848.). Therefore, how to prepare a high-performance stretchable X-ray light detector by a suitable method, and how to apply traditional polymer films to the stretchable X-ray light detection field are two very big challenges at present. SUMMARY

[0004] In view of the deficiencies of the above existing research, the purpose of the present application is to realize the regulation of blended polymer nanometer confinement by eccentric spin coating method, so that the nanometer confined polymer film has unique X-ray light response characteristics. Finally, a high-sensitivity, fast-response and low-dose direct stretchable X-ray light detector is prepared.

[0005] The stretchable X-ray light detector provided by the present application is an organic field effect transistor based on nanometer confined polymer film. Bottom gate top contact and bottom gate bottom contact structures can be used, which specifically include a stretchable substrate, a stretchable insulating layer, a stretchable polymer semiconductor layer, and a stretchable gate and source / drain electrode layer.

[0006] In the stretchable X-ray light detector described above, the X-ray includes soft X-ray and hard X-ray.

[0007] The stretchable X-ray photodetector, wherein the stretchable polymer semiconductor layer is a nano-confined polymer film. The nano-confined polymer film, as an X-ray photosensitive layer, can participate in carrier transport directly while inducing photons.

[0008] The nano-confined polymer film is a blended film prepared by eccentric spin coating of a mixed solution of a conjugated polymer and an elastomeric polymer. Effective control of nano-confinement can be achieved by changing any of the spin coating speed, annealing temperature, and eccentric spin coating distance.

[0009] The conjugated polymer can be a thiophene, a diketopyrrolopyrrole (DPP), an isoindigo (IID), or a naphthalene diimide (NDI) polymer. Specifically, the conjugated polymer can be selected from any of poly{2,5-bis(2-octyldodecyl)-3,6-di(thiophen-2-yl)diketopyrrolopyrrole[3,4-c]pyrrole-1,4-dione-alt-thiophene[3,2-b]thiophene} (DPPT-TT), poly(tetrathiophene diketopyrrolopyrrole) (PTDPPTFT4), poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl} (PIID2T), poly(isoindigo trifluoromethyl thiophene vinyl thiophene) (IID-CF3TVT), poly(fluorinated isoindigo trifluoromethyl thiophene vinyl thiophene) (FIID-CF3TVT), poly{(4,4,9,9-tetrahexadecyl-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)-alt-(benzo[c][1,2,5]thiadiazole-4,7-diyl)} (IDT-BT), poly(3-hexylthiophene) (P3HT), poly{[N,N9-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(diketimine)-2,6-diyl]-alt-5,59-(2,29-bithiophene)} (N2200).

[0010] The elastomeric polymer can be any of an unsaturated rubber: natural rubber (NR), styrene-butadiene rubber (SBR), chloroprene rubber (CR); a saturated rubber: butyl rubber (IIR), ethylene-propylene rubber (EPR), polydimethylsiloxane (PDMS), and a thermoplastic elastomer: hydrogenated styrene-butadiene block copolymer (SEBS), polyacrylate rubber (ABR), and polyurethane elastomer (PU).

[0011] The mixed solution of the conjugated polymer and the elastomeric polymer is a solution prepared by dissolving the conjugated polymer and the elastomeric polymer in at least one of chlorobenzene, dichlorobenzene, chloroform and xylene at a mass ratio of 1-9:9-1 (specifically, 3:7); specifically, the mass concentration of the mixed solution of the conjugated polymer and the elastomeric polymer can be 5 mg / ml-30 mg / ml.

[0012] The thickness of the stretchable polymer semiconductor layer can be 80-150 nm.

[0013] In the stretchable X-ray photodetector described above, the stretchable substrate and the stretchable insulating layer are both made of an elastomeric polymer.

[0014] The elastomeric polymer can be any one of unsaturated rubber: natural rubber (NR), styrene-butadiene rubber (SBR), chloroprene rubber (CR); saturated rubber: butyl rubber (IIR), ethylene-propylene rubber (EPR), polydimethylsiloxane (PDMS), and thermoplastic elastomer: hydrogenated styrene-butadiene block copolymer (SEBS), polyacrylate rubber (ABR) and polyurethane elastomer (PU).

[0015] The thickness of the stretchable substrate can be 500 μm-2 mm.

[0016] The thickness of the stretchable insulating layer can be 1.5 μm-2.5 μm.

[0017] In the stretchable X-ray photodetector described above, the stretchable gate electrode and the source and drain electrodes are both composed of an intrinsically stretchable conductive material.

[0018] The intrinsically stretchable conductive material can be any one of metallic single-walled carbon nanotube: P1-SWNT, P2-SWNT, P3-SWNT, P5-SWNT, P7-SWNT, P8-SWNT, P9-SWNT; metal nanowire: silver nanowire (Ag NWs), gold nanowire (Au NWs), copper nanowire (Cu NWs); liquid metal: gallium-indium alloy (EGaIn); conductive polymer: poly(3,4-ethylenedioxythiophene)-polyethylene phenyl sulfonic acid (PEDOT:PSS).

[0019] The conductivity of the stretchable gate electrode and the source and drain electrodes can be: 1×10 3 S·cm -1 -1×10 5 S·cm -1 .

[0020] The stretchable X-ray photodetector described above is prepared by a method comprising the following steps:

[0021] 1) preparing the stretchable substrate, the stretchable insulating layer, the stretchable polymer semiconductor layer, the stretchable gate electrode and the source and drain electrode on the substrate with self-assembled organosiloxane polymer on the surface respectively;

[0022] wherein the stretchable polymer semiconductor layer is a nano-confined polymer blend film;

[0023] the stretchable polymer semiconductor layer is prepared by eccentric spin coating;

[0024] 2) transferring the stretchable substrate from the substrate with self-assembled molecular layer, covering the stretchable substrate on the stretchable gate electrode by the method of gently adhering from one side to the other side, transferring the stretchable gate electrode to the stretchable substrate by thermal or room temperature adhesion, and vacuuming to remove the bubbles generated at the interface during the adhesion process; then, the stretchable insulating layer, the stretchable polymer semiconductor layer and the stretchable source and drain electrode are transferred to the stretchable substrate by the same method, and a stretchable X-ray photodetector based on polymer semiconductor thin film is prepared.

[0025] In the above preparation method, the substrate is any one of silicon wafer, SiO2-Si silicon substrate, quartz, glass, PET plastic, sapphire substrate, ceramic, metal and hard alloy;

[0026] The substrate with self-assembled organosiloxane polymer is prepared by heating treatment (gas phase modification) or soaking treatment (liquid phase modification) of the substrate and organosiloxane polymer under vacuum conditions;

[0027] The substrate is treated as follows before self-assembly of organosiloxane polymer: sequentially ultrasonic cleaning with deionized water, acetone and isopropanol for 6-7 min, blowing dry with nitrogen, and then ozone treatment (UVO or O3 plasma) to obtain a substrate with surface hydroxyl treatment;

[0028] The organosiloxane polymer is any one of polydimethylsiloxane, octadecyltrimethoxysilane, octadecyltrichlorosilane, octyltrichlorosilane and phenyltrichlorosilane.

[0029] In the above preparation method, the stretchable substrate and the stretchable insulating layer are prepared on the substrate with self-assembled organosiloxane polymer on the surface by any one of drop coating, spin coating, blade coating, bar coating, pulling method and "roll-to-roll" process;

[0030] The solvent used is any one of benzene, toluene, xylene, ethyl acetate, chloroform, dichloromethane, n-hexane, heptane or cyclohexane.

[0031] The stretchable polymer semiconductor layer is prepared by the following steps: a mixed solution of a conjugated polymer and an elastomer polymer is spin-coated on a substrate on which organosiloxane polymers are self-assembled on the surface by eccentric spin coating, and then annealing is performed.

[0032] The speed of the spin coating can be 1000-5000 r / min, and specifically can be 2000 r / min; the eccentric distance can be 1-5 cm, and specifically can be 2 cm; and the spin coating time can be 40 s-1 min, and specifically can be 50 s.

[0033] The annealing temperature can be 100-250 DEG C, and specifically can be 220 DEG C.

[0034] When the stretchable gate electrode and the source and drain electrodes are made of carbon nanotubes, the carbon nanotube electrodes are prepared by a spray coating method or an inkjet printing method on a substrate on which organosiloxane polymers are self-assembled on the surface.

[0035] The solvent used in the carbon nanotube solution can be any one of water, ethanol, isopropanol, chlorobenzene, N-methyl pyrrolidone or a mixed solvent thereof.

[0036] The concentration of the carbon nanotube solution can be 0.1-0.5 mg / ml.

[0037] The spray coating conditions are as follows: the substrate temperature is 60-150 DEG C, the distance between the spray gun and the substrate is 5-20 cm, the spray coating speed is 0.1-3 mL / min, and the spray coating solution volume is 1-5 mL.

[0038] In the above preparation steps, the thermal lamination process is performed in a vacuum drying box.

[0039] The thermal lamination conditions are as follows: the vacuum degree is 0.1-10 Pa, the temperature during the heating treatment is 40-90 DEG C, and the heating treatment time is 0.1-1 hour.

[0040] The application of the stretchable X-ray light detector based on the polymer semiconductor thin film in the preparation of a wearable photoelectric detector also belongs to the protection scope of the present application.

[0041] Beneficial effects: The present application proposes a strategy of eccentric spin coating induced self-assembly of a blended film, and a stretchable polymer thin film with nanometer confinement effect is prepared, and effective control of nanometer confinement is realized. Based on the thin film with nanometer confinement, the prepared stretchable X-ray light detector not only has high sensitivity, fast response and low dose X-ray detection capability, but also has high light transmittance, high stretchability and fatigue resistance. At the same time, the present application has the unique advantages of low cost, large area and high flexibility, greatly promotes the development of X-ray detection and imaging technology, and widens the application prospect of polymer semiconductors in the field of wearable photoelectric detectors. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Structure diagram of the polymer-based stretchable X-ray photodetector provided by the present application, bottom gate top contact structure (a) and bottom gate bottom contact structure (b).

[0043] Figure 2 (a) is a microscope image of a pure polymer film under different tensile strains; (b) is a microscope image of a polymer film prepared by eccentric spin coating in an embodiment of the present application under different tensile strains.

[0044] Figure 3 (a) is a schematic diagram of the preparation method of the polymer film prepared by eccentric spin coating in an embodiment of the present application; (b) is an atomic force microscope image of a polymer film prepared by traditional spin coating; (c) is an atomic force microscope image of a polymer film prepared by eccentric spin coating in an embodiment of the present application.

[0045] Figure 4 The light response curve of the stretchable X-ray photodetector based on the nano-confined polymer film prepared in an embodiment of the present application under different doses of X-rays.

[0046] Figure 5 The photocurrent (a) and photosensitivity (b) of the stretchable X-ray photodetector based on the nano-confined polymer film prepared in an embodiment of the present application under different doses of X-rays.

[0047] Figure 6 The transfer characteristic curve of the stretchable X-ray photodetector based on the nano-confined polymer film prepared in an embodiment of the present application under different tensile deformations in the parallel channel direction (a) and the vertical channel direction (b). DETAILED DESCRIPTION

[0048] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0049] The materials, reagents and the like used in the following examples can be obtained from commercial channels unless otherwise specified.

[0050] The present application provides a stretchable X-ray photodetector based on a nano-confined polymer film and a preparation method thereof. Figure 1 (a) bottom gate top contact and Figure 1 (b) bottom gate bottom contact two structures, including a stretchable substrate, a stretchable insulating layer, a stretchable polymer semiconductor layer, a stretchable gate electrode and a source and drain electrode; the stretchable polymer semiconductor layer is a polymer film with a nano-confined effect, and the nano-confined polymer film as an X-ray photosensitive layer can participate in carrier transport directly while inducing photons.

[0051] The application proposes a strategy of eccentric spin-coating induced self-assembly of a blended film, prepares a stretchable polymer film with a nano-confinement effect, and realizes effective control of the nano-confinement. Based on the nano-confinement film, the prepared stretchable X-ray photodetector not only has the X-ray detection capability of high sensitivity, fast response and low dose, but also has high light transmittance, high stretchability and fatigue resistance. Meanwhile, the application has the unique advantages of low cost, large area and high flexibility, and greatly promotes the development of X-ray detection and imaging technology.

[0052] The nano-confinement polymer film can realize effective control of the nano-confinement by changing any one of a spin-coating speed, an annealing temperature and an eccentric spin-coating distance.

[0053] The thickness of the stretchable polymer semiconductor film is 80-150 nm, preferably 100-130 nm.

[0054] The thickness of the stretchable substrate is 500 mu m-2 mm, preferably 500 mu m-1.5 mm.

[0055] The thickness of the stretchable insulating layer is 1.5 mu m-2.5 mu m, preferably 1.5 mu m-2 mu m.

[0056] In the stretchable X-ray photodetector, the stretchable polymer semiconductor is a blended film of a conjugated polymer and an elastomeric polymer.

[0057] The conjugated polymer can be a thiophene, diketopyrrolopyrrole (DPP), isoindigo (IID), naphthalene diimide (NDI) polymer; specifically, the conjugated polymer can be selected from any one of poly{2,5-bis(2-octyldodecyl)-3,6-di(thiophen-2-yl)diketopyrrolopyrrole[3,4-c]pyrrole-1,4-dione-alt-thiophene[3,2-b]thiophene} (DPPT-TT), poly(tetrathiophene diketopyrrolopyrrole) (PTDPPTFT4), poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl} (PIID2T), poly(isoindigo trifluoromethyl thiophene vinyl thiophene) (IID-CF3TVT), poly(fluorinated isoindigo trifluoromethyl thiophene vinyl thiophene) (FIID-CF3TVT), poly{(4,4,9,9-tetraphexadecyl-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)-alt-(benzo[c][1,2,5]thiadiazole-4,7-diyl)} (IDT-BT), poly(3-hexylthiophene) (P3HT), poly{[N,N9-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(diketimine)-2,6-diyl]-alt-5,59-(2,29-bithiophene)} (N2200);

[0058] The synthesis route of the polymers IID-CF3TVT and FIID-CF3TVT is referred to the patent (Chinese patent 202010098740.9).

[0059] The nanotopography regulation of the blended film and the application in the organic X-ray photodetector belong to the protection scope of the present application. The present application provides a stretchable X-ray photodetector based on a polymer film. In order to make the purpose, technical scheme and effect of the present application more clear and explicit, the technical scheme in the present application will be further described in detail in combination with the drawings in the present application. Obviously, the described examples are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the person skilled in the art without creative labor belong to the protection scope of the present application.

[0060] The current-time curve of the stretchable X-ray photodetector based on the polymer film is tested under the conditions of no X-ray irradiation and different doses of X-ray irradiation, and the differences under the conditions of no X-ray and different doses of X-ray irradiation are compared. The calculation is carried out according to the following formula:

[0061] Photocurrent = current under light condition of transistor-current under no light condition of transistor

[0062] Photosensitivity = (Current of transistor under X-ray illumination - Current of transistor without X-ray illumination) / (X-ray dose x volume of illumination)

[0063] The method for preparing the polymer thin film-based stretchable X-ray photodetector comprises the following steps:

[0064] 1) The silicon wafer is sequentially ultrasonically cleaned with deionized water, acetone and isopropanol for 6-7 min, and then the substrate is treated by ozone oxidation (UVO or O3 plasma) to obtain a surface hydroxylated substrate;

[0065] 2) An organic siloxane polymer modification layer is prepared on the substrate of (1) by gas phase modification or liquid phase modification. The gas phase modification conditions of octadecyltrichlorosilane (OTS) are as follows: after the substrate is cleaned by oxygen plasma, a small amount of OTS is coated on the substrate, and then the substrate is placed in a vacuum oven with a vacuum degree of 0.01 Pa, heated to 120°C and maintained for 3 h, and then naturally cooled to room temperature to complete the modification process;

[0066] 3) The stretchable substrate and the stretchable insulating layer are prepared on the substrate with self-assembled organic siloxane by drop coating, spin coating, blade coating, rod coating, pulling method or "roll-to-roll" process; the stretchable gate electrode and the source and drain electrodes are prepared by spraying or inkjet printing; and the stretchable polymer semiconductor layer is prepared by eccentric spin coating;

[0067] 4) The stretchable substrate is transferred from the substrate with the self-assembled molecular layer, and the stretchable substrate is covered on the stretchable gate electrode by the method of gently adhering from one side to the other side. The stretchable gate electrode is transferred to the stretchable substrate by thermal lamination or room temperature lamination, and the bubbles generated at the interface during lamination are removed by vacuumizing. Then, the stretchable insulating layer, the stretchable polymer semiconductor layer and the stretchable source and drain electrodes are transferred to the stretchable substrate by the same method, and a polymer semiconductor thin film-based stretchable X-ray photodetector is prepared.

[0068] Example 1

[0069] This example is based on a nano-confined FIID-CF3TVT / SEBS polymer blend film, and a bottom-gate top-contact structure stretchable X-ray photodetector is prepared according to the following steps.

[0070] 1) The silicon wafer is sequentially ultrasonically cleaned with deionized water, acetone and isopropanol for 6-7 min, and then the substrate is treated by ozone oxidation (UVO) to obtain a surface hydroxylated substrate;

[0071] 2) Adopting gas phase modification method or liquid phase modification method to prepare organic siloxane polymer modification layer on the substrate of (1). Wherein, the gas phase modification condition of octadecyltrichlorosilane (OTS) is: after the substrate is cleaned by oxygen plasma, a small amount of OTS is coated on the substrate, then the substrate is placed in a vacuum oven with a vacuum degree of 0.01 Pa, then the substrate is heated to 120℃ and maintained for 3h, and then the substrate is naturally cooled to room temperature to complete the modification process.

[0072] 3) The substrate with self-assembled organic siloxane is placed on a hot stage, 1ml of SEBS-H1221 toluene solution (concentration of 200mg / mL) is slowly drawn by a 1ml syringe and uniformly dropped on the silicon wafer with self-assembled molecular layer, then the silicon wafer is first kept at 50℃ for 4h, and then kept at 90℃ for 1h, so that a stretchable substrate with a thickness of 1.2mm is obtained.

[0073] 4) The silicon wafer with self-assembled molecular layer is placed on a hot stage at 80℃ for 5min, 2mL of carbon nanotube P3-SWNT isopropanol solution (0.2mg / mL) is transferred to the capacity tank of a spray pen, and then uniformly sprayed on the silicon wafer with self-assembled molecular layer at a rate of 0.2mL / min (wherein the distance between the spray gun nozzle and the silicon wafer is 10cm), so that a stretchable gate electrode is obtained.

[0074] 5) The silicon wafer with self-assembled molecular layer is placed at the center of a film applicator rotor, 200mL of SEBS-H1052 cyclohexane solution (concentration of 80mg / mL) is drawn by a 1mL syringe, and then uniformly dropped on the silicon wafer with self-assembled molecular layer, and then the film applicator is started and kept at a speed of 1000r / min for 1min. Finally, the silicon wafer is taken out and placed on a hot stage at 80℃ for annealing for 1h, so that a stretchable insulating layer with a thickness of 1.9μm is obtained.

[0075] 6) The silicon wafer with self-assembled molecular layer is placed at the edge of a film applicator, as Figure 2 (a) 20μL of F1ID-CF3TVT / SEBS xylene solution (wherein the mass ratio of the two polymers is 3:7, and the concentration is 10mg / ml) is added dropwise on the silicon wafer by a 50μL syringe, and then spin-coated at a speed of 2000r / min with an eccentric distance of 2cm for 1min, and finally the silicon wafer is placed on a hot stage for annealing at 220℃ for 10min, so that a stretchable polymer semiconductor layer with a thickness of 100nm is obtained. It is worth noting that similar nano-confined morphology can be observed when the spin-coating speed is 1000-5000r / min, the eccentric distance is 1-5cm, the spin-coating time is 40s-1min, and the annealing temperature is 100-250℃.

[0076] 7) The silicon wafer with self-assembled monolayer is placed on a magnet, and a mask plate is placed on the silicon wafer, so that the mask plate is tightly attached to the silicon wafer with self-assembled monolayer. The magnet and the silicon wafer are gently placed on a hot stage at 120°C for 15 minutes. Then 2 mL of carbon nanotube P3-SWNT isopropanol solution (concentration of 0.15 mg / mL) is extracted by a 5 mL pipette, and is uniformly sprayed on the silicon wafer with self-assembled monolayer at a rate of 0.2 mL / min (wherein the distance between the nozzle of the spray gun and the silicon wafer is 12 cm), to obtain a silicon wafer with patterned carbon nanotube source and drain electrodes.

[0077] 8) The stretchable substrate is transferred from the substrate with self-assembled monolayer, and the stretchable substrate is covered on the stretchable gate electrode by gently adhering from one side to the other side. The stretchable gate electrode is transferred to the stretchable substrate by thermal adhesion, and is placed in a vacuum drying box with a vacuum degree of 0.1 Pa at 60°C for 20 minutes to remove the air bubbles generated at the interface during the adhesion. After the temperature is reduced to room temperature, it is taken out. Then the stretchable insulating layer, the stretchable polymer semiconductor layer, and the stretchable source and drain electrodes are transferred to the stretchable substrate by the same method, to obtain a stretchable X-ray photodetector based on a polymer semiconductor thin film.

[0078] Example 2

[0079] In this embodiment, a stretchable X-ray photodetector with bottom gate top contact structure is prepared based on a nano-confined IID-CF3TVT / SEBS polymer blend film according to the following steps.

[0080] The preparation method is completely the same as that in Example 1, except that the polymer IID-CF3TVT / SEBS xylene solution is replaced by IID-CF3TVT / SEBS xylene solution. The stretchable substrate is transferred from the substrate with self-assembled monolayer, and the stretchable substrate is covered on the stretchable gate electrode by gently adhering from one side to the other side. The stretchable gate electrode is transferred to the stretchable substrate by thermal adhesion. Then the stretchable insulating layer, the stretchable polymer semiconductor layer, and the stretchable source and drain electrodes are transferred to the stretchable substrate by the same method, to obtain a stretchable X-ray photodetector based on a polymer semiconductor thin film.

[0081] Example 3

[0082] In this embodiment, a stretchable X-ray photodetector with bottom gate top contact structure is prepared based on a nano-confined N2200 / SEBS polymer blend film according to the following steps.

[0083] The preparation method is completely same as example 1, only the polymer FIID-CF3TVT / SEBS xylene solution is replaced by DPP / SEBS chlorobenzene solution. The stretchable substrate is transferred from the substrate with self-assembled molecular layer, and the stretchable substrate is covered on the stretchable gate electrode by the method of gently adhering from one side to the other side. Then the stretchable gate electrode is transferred to the stretchable substrate by thermal lamination or room temperature lamination method. Subsequently, the same method is taken to transfer the stretchable insulating layer, the stretchable source and drain electrodes and the stretchable polymer semiconductor layer to the stretchable substrate, so as to prepare the stretchable X-ray light detector based on polymer semiconductor thin film.

[0084] Example 4

[0085] In this embodiment, based on the nanometer limited DPP / SEBS polymer blend film, the bottom gate top contact structure stretchable X-ray light detector is prepared according to the following steps.

[0086] The preparation method is completely same as example 1, only the polymer FIID-CF3TVT / SEBS xylene solution is replaced by DPP / SEBS chlorobenzene solution. The stretchable substrate is transferred from the substrate with self-assembled molecular layer, and the stretchable substrate is covered on the stretchable gate electrode by the method of gently adhering from one side to the other side. Then the stretchable gate electrode is transferred to the stretchable substrate by thermal lamination or room temperature lamination method. Subsequently, the same method is taken to transfer the stretchable insulating layer, the stretchable source and drain electrodes and the stretchable polymer semiconductor layer to the stretchable substrate, so as to prepare the stretchable X-ray light detector based on polymer semiconductor thin film.

[0087] Comparative example 1

[0088] In this embodiment, based on the pure FIID-CF3TVT polymer film, the bottom gate top contact structure stretchable X-ray light detector is prepared according to the following steps.

[0089] The preparation method is completely same as example 1, only the polymer FIID-CF3TVT / SEBS xylene solution is replaced by DPP / SEBS chlorobenzene solution. The stretchable substrate is transferred from the substrate with self-assembled molecular layer, and the stretchable substrate is covered on the stretchable gate electrode by the method of gently adhering from one side to the other side. Then the stretchable gate electrode is transferred to the stretchable substrate by thermal lamination or room temperature lamination method. Subsequently, the same method is taken to transfer the stretchable insulating layer, the stretchable source and drain electrodes and the stretchable polymer semiconductor layer to the stretchable substrate, so as to prepare the stretchable X-ray light detector based on polymer semiconductor thin film.

[0090] Figure 2 (a) is a microscope image of a pure polymer film under different tensile strains; (b) is a microscope image of a polymer film prepared by eccentric spin coating according to the embodiment of the application under different tensile strains. From Figure 2 (a) and Figure 2 (b) analysis, the pure semiconductor has a larger crack formation, while the polymer film prepared by eccentric spin coating according to Example 1 has no obvious crack even when stretched to 100%, and has better tensile property.

[0091] Comparative Example 2

[0092] Based on the polymer film of FIID-CF3TVT / SEBS prepared by the conventional spin coating method, the stretchable X-ray photodetector with bottom gate and top contact structure is prepared according to the following steps.

[0093] According to the same preparation method as Example 1, only the eccentric spin coating distance is changed to 0 cm (i.e. the conventional center spin coating method). The stretchable substrate is transferred from the substrate with a self-assembled molecular layer, and then the stretchable substrate is covered on the stretchable gate electrode by the method of gently adhering from one side to the other side. Then the stretchable gate electrode is transferred to the stretchable substrate by heat bonding. Subsequently, the same method is adopted to transfer the stretchable insulating layer, the stretchable polymer semiconductor layer, and the stretchable source and drain electrodes to the stretchable substrate, so as to obtain the stretchable X-ray photodetector based on the polymer semiconductor film.

[0094] Figure 3 (a) is a schematic diagram of the eccentric spin coating preparation method according to Example 1 of the application; (b) is an atomic force microscope image of the polymer film prepared by the conventional spin coating method; (c) is an atomic force microscope image of the polymer film prepared by the eccentric spin coating method according to Example 1 of the application. From Figure 3 (b) and Figure 3 (c) analysis, the polymer film prepared by the eccentric spin coating method according to Example 1 has a clear nano-confined morphology.

[0095] Figure 4 and 5 are the light response curves of the stretchable X-ray photodetector based on the nano-confined polymer film prepared according to Example 1 of the application under different dose X-rays, and the photocurrent (a) and the photosensitivity (b) under different dose X-rays.

[0096] From Figure 4 and Figure 5 analysis, the stretchable X-ray photodetector based on the nano-confined film shows high sensitivity (3×10 8 μC Gy cm -3), fast response (<0.01 s) and low dose (3.5 μGy s -1 ) X-ray detection capability. More importantly, the nanorestricted polymer thin film prepared in Example 1 has high strain bearing capacity and can also exhibit ideal transfer characteristic curves ( Figure 6 ) under up to 100% tensile strain. For example, the electrical performance of the detector does not significantly decay under 0% and 100% tensile strain. Generally, 0%-25% tensile strain can be suitable for most wearable electronic products. Therefore, the stretchable X-ray photodetector based on the nanorestricted polymer thin film prepared in the example can fully meet the requirements of practical applications.

Claims

1. A stretchable X-ray photodetector based on a polymer semiconductor thin film, characterized by: The stretchable X-ray photodetector is an organic field-effect transistor based on a polymer thin film under nano-confined conditions. It adopts a bottom-gate top contact or bottom-gate bottom contact structure, including a stretchable substrate, a stretchable insulating layer, a stretchable polymer semiconductor layer, and stretchable gate electrode and source and drain electrode layers; Among them, the stretchable polymer semiconductor layer is a nano-confined polymer thin film; The nano-confined polymer film serves as an X-ray photosensitive layer, directly participating in carrier transport while inducing photons. The nano-confined polymer film is a blend film prepared by spin-coating a mixed solution of a conjugated polymer and an elastomer polymer eccentrically. The conjugated polymers are thiophene, pyrrolopyrrole dione, isoindigo, and naphthalimide polymers; The elastomer polymer is any one of unsaturated rubber, saturated rubber, and thermoplastic elastomer; The conjugated polymer is selected from 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}, poly(tetrathiopheneacetic acid dionepyrrole), poly{2,2'-(2,5-bis(2-octyldodecyl)-3,6-isoindigo-alt-thiophene-2,5-diyl}, poly(isoindigotrifluoromethylthiophene vinylthiophene), poly(fluorinated isoindigotrifluoromethylthiophene vinylthiophene), poly{ Any one of (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)}, poly(3-hexylthiophene), or poly{[N,N9-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,59-(2,29-benzothiophene)}; The unsaturated rubber is natural rubber, styrene-butadiene rubber, or chloroprene rubber; The saturated rubber is butyl rubber, ethylene propylene rubber, or polydimethylsiloxane; The thermoplastic elastomer is any one of hydrogenated styrene-butadiene block copolymer, polyacrylate rubber, and polyurethane elastomer; The mixed solution of the conjugated polymer and the elastomer polymer is a solution prepared by dissolving the conjugated polymer and the elastomer 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 5 mg / ml - 30 mg / ml; Both the stretchable substrate and the stretchable insulating layer are made of elastomeric polymers; The elastomer polymer is any one of unsaturated rubber, saturated rubber, and thermoplastic elastomer; The thickness of the stretchable substrate is 500 µm-2 mm; The thickness of the stretchable insulating layer is 1.5 µm-2.5 µm; The thickness of the stretchable polymer semiconductor layer is 80-150 nm; The stretchable gate electrode and the source and drain electrodes are all composed of intrinsically stretchable conductive materials. The intrinsic stretchable conductive material is any one of metallic single-walled carbon nanotube, metallic nanowire, liquid metal and conductive polymer. The conductivity of the stretchable gate electrode and source / drain electrodes is: 1 x 10 3 S·cm -1 -1 x 10 5 S·cm -1 .

2. The stretchable X-ray light detector according to claim 1, characterized in that: The X-ray includes soft X-ray and hard X-ray.

3. A method for preparing the stretchable X-ray photodetector according to claim 1 or 2, comprising the following steps: 1) preparing the stretchable substrate, the stretchable insulating layer, the stretchable polymer semiconductor layer, the stretchable gate electrode and the source and drain electrode on the substrate with self-assembled organosiloxane polymer respectively; 2) transferring the stretchable substrate from the substrate with self-assembled molecular layer, covering the stretchable substrate on the stretchable gate electrode by the method of gently adhering from one side to the other side, transferring the stretchable gate electrode to the stretchable substrate by hot or room temperature adhesion method, and vacuumizing to remove the bubbles generated in the interface during the adhesion process; 3) transferring the stretchable insulating layer, the stretchable polymer semiconductor layer and the stretchable source and drain electrode to the stretchable substrate by the same method, thereby obtaining the stretchable X-ray photodetector based on polymer semiconductor thin film. wherein, In step 1), the stretchable polymer semiconductor layer is prepared by eccentric spin coating method of mixed solution of conjugated polymer and elastomer polymer on the substrate with self-assembled organosiloxane polymer, and is prepared after annealing. The speed of spin coating is 1000-5000 r / min, the eccentric distance is 1-5 cm, and the time of spin coating is 40 s-1 min. The annealing temperature is 100-250°C.

4. The method of claim 3, wherein:

6. The use of the stretchable X-ray photodetector according to claim 1 or 2 in the preparation of wearable photodetector.

5. The method of claim 4, wherein: ​ ​ ​

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