High-sensitivity double-channel coordinated regulation organic field effect opto-transistor and preparation method thereof

Abstract

The invention discloses a high-sensitivity double-channel coordinated regulation organic field effect opto-transistor and a preparation method thereof. The organic field effect opto-transistor sequentially comprises a gate electrode, an insulating layer, an organic semiconductor layer I, a dielectric layer, an organic semiconductor layer II, a source electrode and a drain electrode from bottom to top. The organic semiconductor layer I and the organic semiconductor layer II are polymer layers made of the same material. According to the double-channel coordinated regulation and control organic field effect opto-transistor disclosed by the invention, the super-flexible double-channel coordinated regulation and control organic field effect opto-transistor can be formed. According to the invention, the phenomena that the organic semiconductor exciton binding energy is large and photo-generated excitons are difficult to separate are solved, and the dissociation efficiency of photo-generated carriers is effectively improved through the interface capture effect of double channels; the high charge transfer efficiency is ensured while the exciton dissociation efficiency is improved, and in addition, the light absorption coefficient can be increased through introduction of the double-layer semiconductor; according to the invention, a high-sensitivity large-area phototransistor array can be prepared through an all-solution method, the high integration level is realized, and industrial production is facilitated.

Description

Technical Field

[0001] The invention relates to a highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor and a preparation method thereof, and belongs to the field of organic optoelectronics. Background Art

[0002] Field-effect phototransistors combine the unique advantages of light detection and signal amplification, and have a wide range of applications in the fields of bioimaging, health monitoring, photothermal therapy, and telecommunications, which have attracted great interest ( Chem. Soc. Rev. 2020, 49, 653; Nat. Electron. 2020, 3, 251; Nat. Rev. Mater. 2020, 5, 149; Adv. Mater. 2021, 33, 2102812). Photosensitivity is one of the key performance parameters for evaluating photodetectors. High sensitivity can effectively improve the signal-to-noise ratio of photodetectors, which is crucial for achieving high-quality imaging ( Chem. Mater. 2019, 31, 6359; Adv. Funct. Mater. 2021, 31, 2103787; Adv. Sci. 2019, 6,1901050). Compared with inorganic semiconductor materials, organic materials have a series of unique characteristics such as bandgap tunability, inherent mechanical flexibility, low-temperature preparation and large-area manufacturing, which make them have unique advantages in the application of future electronic products. However, organic phototransistors usually show poor photosensitivity (<10 3 ), because organic semiconductors (0.3-1 eV) usually have higher exciton binding energy than inorganic semiconductors (0.002-0.3 eV), which will lead to low dissociation efficiency of photogenerated excitons ( Chem. Soc. Rev. 2020, 49, 653).

[0003] At present, there are two main ways to improve the photosensitivity of organic field-effect phototransistors: (1) One way is to use a single-layer bulk heterojunction to prepare an organic field-effect phototransistor. The photosensitive active layer is prepared by mixing donor and acceptor solutions. The increased specific surface area is conducive to the absorption and charge separation of photogenerated excitons at the junction interface ( Nanoscale 2013, 5,11850; Adv. Funct. Mater. 2016, 26, 6306; Adv. Mater. 2020, 32, 2001763; Adv. Funct. Mater. 2020, 30, 1904205; Adv. Mater. 2020, 32, 1906027; Adv. Optical Mater.2023, 11, 2202008). For example, Tang Qingxin's research group used p-type polymer semiconductor DPPT-TT and n-type polymer semiconductor N2200 to construct a bulk heterojunction photosensitive layer ( Adv. Funct. Mater. 2022, 32, 2206765). By optimizing the insulating layer interface, the mixing ratio of the donor and acceptor solutions, and the annealing conditions of the photosensitive layer, a nanoscale bicontinuous phase separation network was formed, which enabled the phototransistor device to be powered under dim illumination (0.038 mW cm -2 ) The photosensitivity can be increased to 10 6 . The advantages of this method of preparing high-performance organic field-effect phototransistors by blending donor and acceptor solutions are: the bulk heterojunction structure can effectively capture one type of carrier in one component, while allowing carriers with opposite charges in the other component to be quickly transferred; this blended heterojunction structure can better increase the specific surface area of ​​the two components and can effectively increase the dissociation efficiency of photogenerated excitons. The disadvantages of this method are: a large amount of additional acceptor phase will affect the charge transfer in the conductive channel, which inevitably reduces the transmission efficiency of photogenerated charge carriers, thereby limiting the further improvement of photosensitivity; in addition, there may be defects and impurities at the bulk heterojunction interface, forming interface states, which can capture mobile carriers and lead to higher dark current. (2) Another method is to use different semiconductor materials to form the charge transport layer and the photosensitive layer respectively. Organic field-effect phototransistors are generally prepared by layer-by-layer deposition. The constructed heterojunction can improve the dissociation efficiency of excitons ( Org. Electron. 2013, 14, 1045; Adv. Opt. Mater. 2017, 5,1700655;Adv. Funct. Mater. 2018, 28, 1800704; NPJ Flex. Electron. 2021, 5, 10; Adv. Funct. Mater. 2021, 2103787; Results Phys. 2023, 48, 106456 For example, Liu Yunqi's research group proposed a solution-processed double-layer heterostructure of a polymer phototransistor, which uses a cross-linked polymer semiconductor PDPP-DTT as the bottom conductive channel and a blended bulk heterojunction structure semiconductor as the photoactive layer, and its photosensitivity is improved by 3 to 4 orders of magnitude ( Appl. Mater. Today2021, 22,100899). The advantage of this method of preparing organic field-effect phototransistors using a double-layer structure is that the mixed acceptor phase can effectively improve the dissociation efficiency of excitons through the junction interface and avoid the acceptor phase affecting the charge transfer in the conductive channel. In addition, compared with bulk heterojunction devices, the electron capture effect generated between the bulk heterojunction interface is avoided, and the dark current of the device is significantly reduced. The disadvantage of this method is that due to the short diffusion distance of photogenerated excitons, most excitons cannot effectively diffuse into the transmission channel, which limits the dissociation efficiency of excitons, making it difficult to greatly improve the photosensitivity. Therefore, it is necessary to provide a novel preparation method for improving the photosensitivity of organic field-effect phototransistors, which can not only ensure a high light absorption coefficient and the dissociation efficiency of photogenerated excitons, but also ensure the effective transmission efficiency of photogenerated charge carriers. Summary of the invention

[0004] The purpose of the present invention is to provide a highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor. The dual-channel cooperatively regulated organic field-effect phototransistor is prepared by multi-layer stacking, and the prepared device has excellent photosensitivity and specific detection rate.

[0005] The dual-channel cooperatively regulated organic field-effect phototransistor of the present invention is a bottom-gate top-contact configuration, and its photosensitive active layer is a sandwich structure (semiconductor-dielectric-semiconductor). By introducing a polymer dielectric with polar hydrophilic function, it is sandwiched between double-layer semiconductors as a special functional layer to prevent the lower semiconductor from being damaged by the solvent; due to the unique hydrophilicity of the dielectric, intramolecular and intermolecular hydrogen bonds can be formed between molecular chains, and protons can migrate along a continuous hydrogen bond network under the action of an electric field; the migrated protons can induce more charge carriers to participate in transmission at the lower interface of the upper semiconductor, and at the same time, the lower interface of the lower semiconductor can form a conductive channel under the action of an electric field; the introduction of the double-layer semiconductor increases the intensity of light absorption, and the formed dual channels can be cooperatively regulated to improve the detection performance of the phototransistor.

[0006] The highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor provided by the present invention comprises, from bottom to top, a gate electrode, an insulating layer, an organic semiconductor layer I, a dielectric layer, an organic semiconductor layer II, a source electrode and a drain electrode; The organic semiconductor layer I and the organic semiconductor layer II are polymer layers made of the same material; The organic semiconductor layer I and the organic semiconductor layer II serve together as a photosensitive layer and a channel transmission layer of an organic field effect transistor.

[0007] Preferably, the material of the organic semiconductor layer I and the organic semiconductor layer II is polydithiophene-pyrrolopyrrole diketo (DPPT-TT), poly [4-(4,4-hexadecyl-4H-cyclopenta[1,2-b:5,4-b'-dithiophene-2-yl)-alt-[1,2,5]thiadiazo[3,4-c]pyridine] (PCDTPT) or indenodithiophene-benzothiadiazole (PIDTBT).

[0008] Preferably, the thickness of the organic semiconductor layer I and the organic semiconductor layer II are both 30-50 nm.

[0009] Preferably, the dielectric layer is made of a polar hydrophilic polymer; The polar hydrophilic functional polymer is preferably polyvinyl alcohol; The thickness of the dielectric layer is 50-70 nm.

[0010] Preferably, the source electrode and the drain electrode may be made of metal gold.

[0011] The present invention further provides a method for preparing the dual-channel cooperatively regulated organic field-effect phototransistor, comprising the following steps: S1, depositing an organic semiconductor on a substrate to form the organic semiconductor layer I; S2, depositing a polymer dielectric on the organic semiconductor layer I to form the dielectric layer; S3, depositing the organic semiconductor on the dielectric layer to form the organic semiconductor layer II; S4, vapor-depositing metal on the organic semiconductor layer II to form the source electrode and the drain electrode, thereby obtaining the highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor.

[0012] In step S1, the substrate is a silicon dioxide substrate, which serves as the gate electrode and the insulating layer; In addition, the gate electrode may also be a hard substrate electrode, such as silicon dioxide, or a flexible electrode, such as gold, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS); The insulating layer may also be a hard substrate, such as silicon dioxide, or a flexible insulating layer, such as epoxy resin, pullulan, dextran, or pectin.

[0013] The substrate is modified with octadecyltrichlorosilane; The octadecyltrichlorosilane is modified by a gas phase method, comprising the following steps: treating the cleaned silicon dioxide substrate with oxygen plasma and placing it in a vacuum drying oven; placing the octadecyltrichlorosilane in the vacuum drying oven; heating the vacuum drying oven, and when the vacuum drying oven is cooled to room temperature, taking out the substrate and then placing it in chloroform for ultrasonic treatment, that is, modifying the surface of the substrate with octadecyltrichlorosilane.

[0014] In steps S1 and S3, the organic semiconductor I and the organic semiconductor II are deposited by a liquid phase method: The dissolved organic semiconductor solution is spin-coated and then placed in a drying oven for curing; The solvent for dissolving the organic semiconductor is chloroform, and the concentration can be 3-5 mg mL -1 ; The rotation speed of spin coating the organic semiconductor solution is 3000-6000 rpm, and the time is 40-60 s; The temperature for curing the organic semiconductor I or the organic semiconductor II is 100-150° C. and the time is 20-60 minutes.

[0015] In step S2, the polymer dielectric solution is spin-coated on the organic semiconductor layer I, and the dielectric layer is obtained by curing; The solvent for dissolving the polymer dielectric is deionized water, and the concentration can be 2-5%; The polymer dielectric solution is spin-coated at a speed of 6000-8000 rpm for 30-60 s; The temperature for curing the polymer dielectric layer is 60-80° C. and the time is 20-40 min.

[0016] The dual-channel cooperatively regulated organic field-effect phototransistor provided by the present invention can form an ultra-flexible dual-channel cooperatively regulated organic field-effect phototransistor.

[0017] The method for preparing a highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor provided by the present invention has a simple process and is suitable for preparing a fully solution-processed dual-channel organic field-effect phototransistor by stacking multiple layers. The method is suitable for a variety of organic polymer semiconductor materials. Since a sandwich structure (semiconductor-dielectric-semiconductor) is used as the photosensitive layer of the phototransistor, a dual-channel cooperatively regulated effect is formed, thereby ensuring high exciton dissociation efficiency and high charge transfer efficiency of the phototransistor. The device prepared by the present invention can achieve ultra-high photoelectric sensitivity (~10 8 ) and specific detection rate (~10 16Jones), the photosensitivity of the device is improved by five orders of magnitude, which is better than most all-solution organic near-infrared phototransistors; the preparation method provided by the present invention solves the problem that the organic semiconductor exciton binding energy is large and the photogenerated excitons are difficult to separate, and effectively improves the dissociation efficiency of photogenerated carriers through the interface capture effect of the double channel; the method provided by the present invention improves the exciton dissociation efficiency while ensuring high charge transfer efficiency, and in addition, the light absorption coefficient can be increased by introducing a double-layer semiconductor; the present invention can prepare a highly sensitive large-area phototransistor array through a full solution method, achieve high integration, and facilitate industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of a dual-channel cooperatively controlled organic field-effect phototransistor.

[0019] Figure 2 It is a microscope image of the DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor prepared in Example 1 of the present invention.

[0020] Figure 3 The transfer curves of the DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor prepared in Example 1 of the present invention under no illumination and illumination conditions ( Figure 3 (a)) and output curve (3(b)).

[0021] Figure 4 The photosensitivity and photoresponse of the DPPT-TT dual-channel coordinated regulation organic field effect phototransistor with gate voltage change are prepared in Example 1 of the present invention ( Figure 4 (a)), and the external quantum efficiency and specific detectivity ( Figure 4 (b)).

[0022] Figure 5 It is the ultraviolet-visible-near-infrared absorption spectrum of the semiconductor layer, dielectric layer, and semiconductor / dielectric / semiconductor layer of the DPPT-TT dual-channel coordinated regulation organic field effect phototransistor prepared in Example 1 of the present invention.

[0023] Figure 6 The transfer curve of the DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor prepared in Example 1 of the present invention under different light power densities ( Figure 6 (a)) and the transfer curves of the organic field effect phototransistor prepared after removing the semiconductor layer-2 under different light power densities ( Figure 6 (b)).

[0024] Figure 7 Schematic diagram of the structure of the PCDTPT dual-channel cooperatively regulated organic field-effect phototransistor prepared in Example 2 of the present invention ( Figure 7(a)) and the transfer light addition curve ( Figure 7 (b)).

[0025] Figure 8 The PCDTPT dual-channel synergistically regulated photosensitivity and photoresponse of the organic field-effect phototransistor with gate voltage changes prepared in Example 2 of the present invention ( Figure 8 (a)) and external quantum efficiency and specific detectivity ( Figure 8 (b)). DETAILED DESCRIPTION

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0027] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0028] Example 1: Preparation of DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor (1) Octadecyltrichlorosilane was used to modify the surface of the silica substrate by a gas phase method: the cleaned silica substrate was treated with oxygen plasma (for 30 s), and then placed in a vacuum drying oven, and octadecyltrichlorosilane was placed in the vacuum drying oven; the vacuum drying oven was heated (temperature was 60 °C), and the silica substrate was taken out; the silica substrate was placed in chloroform and ultrasonicated, and then taken out and dried with nitrogen, thereby modifying the surface of the silica substrate with octadecyltrichlorosilane.

[0029] (2) Depositing DPPT-TT on the surface of the silicon dioxide substrate after step (1): Depositing the organic semiconductor material DPPT-TT by spin coating by a liquid phase method at room temperature, and curing (temperature of 100°C for 30 min). The thickness of the DPPT-TT layer deposited on the surface of the silicon dioxide substrate is 40 nm. The DPPT-TT layer covers the surface of the silicon dioxide substrate to form an organic semiconductor layer-1.

[0030] (3) Depositing PVA on the surface of the DPPT-TT organic semiconductor layer-1 obtained in step (2): Spin-coating the polymer dielectric PVA on the surface of the organic semiconductor material DPPT-TT layer and curing it (temperature: 70 °C, time: 30 min) to form a dielectric layer with a thickness of 60 nm; (4) Depositing DPPT-TT on the surface of the PVA / DPPT-TT substrate obtained in step (3): Depositing the organic semiconductor material DPPT-TT by spin coating at room temperature, and curing (temperature of 100 °C for 20 min). The thickness of the DPPT-TT layer deposited on the surface of the PVA dielectric layer is 40 nm. The DPPT-TT layer covers the surface of the PVA layer to form a DPPT-TT organic semiconductor layer-2.

[0031] (5) Evaporating source and drain metal electrodes on the surface of the DPPT-T / PVA / DPPT-TT substrate obtained in step (4): Depositing source and drain metal electrodes Au by evaporation, the thickness of Au deposited on the DPPT-TT layer is 30 nm, and the Au electrode is deposited on the surface of the DPPT-TT organic semiconductor layer-2 through a mask to form patterned source and drain electrodes. Finally, a highly photosensitized DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor is formed.

[0032] Figure 1 This is a schematic diagram of the structure of the prepared dual-channel cooperatively controlled organic field-effect phototransistor.

[0033] Figure 2 This is a microscope image of the prepared DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor.

[0034] Figure 3 The transfer curves of the prepared DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor under no light and light conditions ( Figure 3 (a)) and output curve (3(b)). When light is added, it can be clearly seen that the current values ​​of the transfer curve and the output curve increase significantly. The device is illuminated (808 nm, 0.14 mW cm -2 ) Maximum photosensitivity ( P ) is 1.98×10 8 .

[0035] Figure 4 The prepared DPPT-TT dual-channel coordinated regulation of the photosensitivity and photoresponse of the organic field-effect phototransistor with gate voltage changes ( Figure 4 (a)). All devices exhibit controllable optoelectronic performance by adjusting the gate voltage. The gate voltage is swept from -20 to 10 V, and the maximum is observed at the on-gate voltage (-3 V). P Value is about 10 8 , the maximum photoresponse ( R ) is 33 AW -1 In order to further evaluate the device performance of the organic field effect phototransistor, the present invention also I DS -V G The external quantum efficiency (EQE) and specific detectivity ( D *) curve ( Figure 4 (b)). It can be seen that the organic field-effect phototransistor shows an EQE value as high as 5122% at a gate voltage of -5 V, and the maximum EQE value is at a gate voltage of -3 V. D *The value is calculated as 1.12×10 16 Jones. The present invention provides a dual-channel coordinated control of an organic field-effect phototransistor P , R , EQE and D *The characteristic parameters have been significantly improved.

[0036] The dual-channel cooperatively regulated organic field-effect phototransistor of the present invention shows obvious advantages over the reported polymer field-effect phototransistor in multiple parameters. For photodetector imaging, high P The value indicates the ability to distinguish signals, thereby producing relatively clear imaging. In particular, the dual-channel device of the present invention P The value is higher than that of most existing polymer organic field-effect phototransistors, as shown in Table 1.

[0037] Figure 5 The prepared DPPT-TT dual-channel cooperatively regulates the UV-visible-near-infrared absorption spectra of each layer in the organic field-effect phototransistor. The PVA film, DPPT-TT film and DPPT-TT / PVA / DPPT-TT film were deposited on a quartz substrate respectively. The PVA film has no absorption in the ultraviolet to near-infrared light band. The DPPT-TT film has characteristic absorption peaks in the visible light (430nm) and near-infrared (808nm) regions. The spectrum of the DPPT-TT / PVA / DPPT-TT film combines the absorption of the double-layer DPPT-TT film. The absorption peak of the multilayer film remains in the near-infrared characteristic absorption band, and the light absorption intensity is significantly enhanced due to the superposition effect.

[0038] Figure 6 The transfer curves of the prepared DPPT-TT dual-channel cooperatively regulated organic field-effect phototransistor under different light power densities ( Figure 6 (a)). As the optical power density increases, the current of the transfer curve increases linearly. It reaches its maximum near the threshold voltage. P In order to compare the effect of dual-channel coordinated regulation, the organic field-effect phototransistor prepared by removing the semiconductor layer-2 is shown in its structure diagram and transfer curve under different light power density irradiation ( Figure 6 (b)). When the device is not illuminated, the on-current is significantly lower than that of the dual-channel device. The current of the device of the present invention does not change significantly under different illumination conditions.

[0039] Table 1 Performance of existing near-infrared all-polymer organic field-effect phototransistors

[0040] P : Photosensitivity, R : Photoresponse, EQE: External Quantum Efficiency, D* : Ratio detection rate.

[0041] The documents are as follows: [1] J. Sun, J. Jiang, Y. Deng, Y. Wang, L. Li, Z. Lou, Y. Hou, F.Teng, Y. Hu, ACS Appl. Mater. Inter. 2022, 14, 57082. [2] N. Li, Y. Lei, Y. Miao, F. Zhu, iScience 2022, 25 , 103711. [3] S. Kim, D. Lee, J. Lee, Y. Cho, SH Kang, W. Choi, JH Oh, C.Yang, Chem. Mater. 2021, 33 , 7499. [4] M. Shou, Q. Zhang, H. Li, S. Xiong, B. Hu, J. Zhou, N. Zheng, Z. Xie, L. Ying, L. Liu, Adv. Opt. Mater. 2021, 9 , 2002031. [5] Y. Tang, H. Fu, N. Li, Y. Hu, L. Chen, W. Jia, Q. Zhang, Y. Lei, Adv. Opt. Mater. 2023, 11 , 2202008. [6] L. Ma, Z. Li, B. Chen, P. Xue, Z. Wang, Y. Wu, X. Zhan, Y. Liu, X. Chen, Adv. Electron. Mater. 2022, 8 , 2101297. [7] T. Han, Z. Wang, N. Shen, Z. Zhou, X. Hou, S. Ding, C. Jiang, X. Huang, X. Zhang, L. Liu, Nat. Commun. 2022, 13 , 1332. [8] B. Yang, Y. Wang, L. Li, J. Zhang, J. Wang, H. Jiao, D. Hao, P. Guo, S. Zeng, Z. Hua, J. Huang, Adv. Funct. Mater. 2021, 31 , 2103787. [9]H. Yu, X. Zhao, M. Tan, B. Wang, M. Zhang, X. Wang, S. Guo, Y. Tong, Q. Tang, Y. Liu, Adv. Funct. Mater. 2022, 32 , 2206765. Example 2: Preparation of PCDTPT dual-channel cooperatively regulated organic field-effect phototransistor (1) Octadecyltrichlorosilane was used to modify the surface of the silica substrate by a gas phase method: the cleaned silica substrate was treated with oxygen plasma (for 30 s), and then placed in a vacuum drying oven, and octadecyltrichlorosilane was placed in the vacuum drying oven; the vacuum drying oven was heated (temperature was 60 °C), and the silica substrate was taken out; the silica substrate was placed in chloroform and ultrasonicated, and then taken out and dried with nitrogen, thereby modifying the surface of the silica substrate with octadecyltrichlorosilane.

[0042] (2) Depositing PCDTPT on the surface of the silicon dioxide substrate after step (1): Depositing the organic semiconductor material PCDTPT by spin coating by liquid phase method at room temperature, and curing (temperature of 100 °C for 30 min). The thickness of the PCDTPT layer deposited on the surface of the substrate is 30 nm. The PCDTPT layer covers the surface of the silicon dioxide substrate to form a PCDTPT organic semiconductor layer-1.

[0043] (3) Depositing PVA on the surface of the PCDTPT organic semiconductor layer-1 obtained in step (2): Spin-coat the polymer dielectric PVA on the surface of the organic semiconductor material PCDTPT layer and cure it (temperature: 70 °C, time: 30 min) to form a dielectric layer with a thickness of 60 nm.

[0044] (4) PCDTPT was deposited on the surface of the PVA / PCDTPT substrate obtained in step (3): the organic semiconductor material PCDTPT was deposited by spin coating at room temperature, and cured (temperature was 100 °C, time was 20 min), the thickness of the PCDTPT layer on the surface of the deposited dielectric layer PVA was 30 nm, and the PCDTPT layer covered the surface of the PVA dielectric layer to form a PCDTPT organic semiconductor layer-2.

[0045] (5) Evaporating source and drain metal electrodes on the surface of the DPPT-TT / PCDTPT / DPPT-TT substrate obtained in step (4): Depositing source and drain metal electrodes Au by evaporation, the thickness of Au deposited on the PCDTPT layer is 30 nm, and the Au electrode is deposited on the surface of the PCDTPT organic semiconductor layer-2 through a mask to form patterned source and drain electrodes. Finally, a PCDTPT dual-channel cooperatively regulated organic field-effect phototransistor is formed.

[0046] Figure 7 This is a schematic diagram of the structure of the prepared PCDTPT dual-channel cooperatively regulated organic field-effect phototransistor ( Figure 7 (a)) and the transfer light addition curve ( Figure 7 (b)). When light is added, it can be clearly seen that the current value of the transfer curve increases significantly with the change of different light power densities.

[0047] Figure 8 The prepared PCDTPT dual-channel synergistically regulates the photosensitivity and photoresponse of organic field-effect phototransistors as the gate voltage changes ( Figure 8 (a)). All devices exhibit controllable optoelectronic performance by adjusting the gate voltage. The gate voltage is swept from -20 to 10 V, and the maximum is observed at the on-gate voltage (2 V). P Value is about 10 4 , the largest R 2.64AW -1 In order to further evaluate the device performance of the organic field effect phototransistor, the present invention also I DS - V G The EQE and D *The curve ( Figure 8 (b) It can be seen that the organic field-effect phototransistor of the present invention shows an EQE value as high as 808% at a gate voltage of -20 V, and the maximum EQE value is 2 V when the gate voltage is 2 V. D *Value calculated as 1.35×10 14 Jones. The present invention provides a dual-channel coordinated control of an organic field-effect phototransistor P , R , EQE andD *The characteristic parameters have been significantly improved.

Claims

1. A highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor, which comprises, from bottom to top, a gate electrode, an insulating layer, an organic semiconductor layer I, a dielectric layer, an organic semiconductor layer II, a source electrode and a drain electrode; The organic semiconductor layer I and the organic semiconductor layer II are polymer layers made of the same material.

2. The dual-channel cooperatively controlled organic field-effect phototransistor according to claim 1, characterized in that: The material of the organic semiconductor layer I and the organic semiconductor layer II is polydithiophene-pyrrolopyrrole dione, poly [4-(4,4-hexadecyl-4H-cyclopenta[1,2-b:5,4-b'-dithiophene-2-yl)-alt-[1,2,5]thiadiazo[3,4-c]pyridine] or indenodithiophene-benzothiadiazole.

3. The dual-channel cooperatively controlled organic field-effect phototransistor according to claim 1 or 2, characterized in that: The thickness of the organic semiconductor layer I and the organic semiconductor layer II are both 30-50 nm.

4. The dual-channel cooperatively controlled organic field-effect phototransistor according to any one of claims 1 to 3, characterized in that: The material of the dielectric layer is a polar hydrophilic polymer; The thickness of the dielectric layer is 50-70 nm.

5. The method for preparing the dual-channel cooperatively regulated organic field-effect phototransistor according to any one of claims 1 to 4, comprising the following steps: S1, depositing an organic semiconductor on a substrate to form the organic semiconductor layer I; S2, depositing a polymer dielectric on the organic semiconductor layer I to form the dielectric layer; S3, depositing the organic semiconductor on the dielectric layer to form the organic semiconductor layer II; S4, vapor-depositing metal on the organic semiconductor layer II to form the source electrode and the drain electrode, thereby obtaining the highly sensitive dual-channel cooperatively regulated organic field-effect phototransistor.

6. The preparation method according to claim 5, characterized in that: In step S1, the substrate is a silicon dioxide substrate, which serves as the gate electrode and the insulating layer; The substrate is modified with octadecyltrichlorosilane.

7. The preparation method according to claim 6, characterized in that: The octadecyltrichlorosilane is modified by a gas phase method, comprising the following steps: treating the cleaned silicon dioxide substrate with oxygen plasma and placing it in a vacuum drying oven; placing the octadecyltrichlorosilane in the vacuum drying oven; heating the vacuum drying oven, and when the vacuum drying oven is cooled to room temperature, taking out the substrate and then placing it in chloroform for ultrasonic treatment, that is, modifying the surface of the substrate with octadecyltrichlorosilane.

8. The preparation method according to any one of claims 5 to 7, characterized in that: In steps S1 and S3, the organic semiconductor I and the organic semiconductor II are deposited by a liquid phase method: The dissolved organic semiconductor solution is spin-coated and then placed in a drying oven for curing; The solvent for dissolving the organic semiconductor is chloroform; The rotation speed of spin coating the organic semiconductor solution is 3000-6000 rpm, and the time is 40-60 s; The temperature for curing the organic semiconductor I or the organic semiconductor II is 100-150° C., and the time is 20-60 min.

9. The preparation method according to any one of claims 5 to 8, characterized in that: In step S2, the polymer dielectric solution is spin-coated on the organic semiconductor layer I, and the dielectric layer is obtained by curing.

10. The preparation method according to claim 9, characterized in that: The solvent for dissolving the polymer dielectric is deionized water; The polymer dielectric solution is spin-coated at a speed of 6000-8000 rpm for 30-60 s; The temperature for curing the polymer dielectric layer is 60-80° C. and the time is 20-40 min.

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