A flexible photodetector with broadband infrared response

Abstract

The present invention provides a flexible photodetector with broadband infrared response, which belongs to the field of photoelectric detection technology. The flexible photodetector of the present invention comprises: a substrate, a photosensitive layer and an electrode. Among them, the substrate is a flexible substrate; the photosensitive layer is arranged on the substrate, and the photosensitive layer is a thin film formed by blending P-type material and N-type material; the electrode is arranged on the photosensitive layer; and at least one of the P-type material and the N-type material has a photoelectric response to infrared band light. The flexible photodetector with broadband infrared response of the present invention makes up for the shortcomings of the performance of a single material by blending P-type material and N-type material on a flexible substrate to form a composite photosensitive layer, so that the flexible photodetector has both good mechanical recovery ability and wide infrared response performance, ensuring that the flexible photodetector can still maintain a stable and efficient photoelectric response to infrared band light after multiple bending and deformation.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric detection, and in particular to a flexible photoelectric detector with broadband infrared response. Background Art

[0002] Flexible electronics is one of the hot topics in interdisciplinary research, which can promote the application of post-Moore technology in biomedicine, electronic skin, wearable devices and other fields. Compared with electronic devices on rigid substrates, flexible substrates show promising advantages, such as easy mobility, bendability, stretchability, low cost and seamless heterogeneous integration, which can provide multiple possibilities for multifunctional and miniaturized next-generation electronic and optoelectronic devices. For example, ultrathin flexible electrode arrays can be mounted on the surface of epidermis or organs for real-time monitoring of human health, which is not possible with traditional rigid electronic devices. Therefore, there is an urgent need for flexible electronics with new functional materials that can meet the requirements of high performance and have good stability and durability under repeated bending, folding or stretching.

[0003] Therefore, it is necessary to design a flexible photodetector with broadband infrared response that can take into account both good mechanical recovery ability and broadband infrared response, so as to solve the above problems. Summary of the invention

[0004] In view of the above shortcomings of the prior art, the present invention provides a flexible photodetector with broadband infrared response, which makes up for the shortcomings of the performance of a single material by blending P-type material and N-type material on a flexible substrate to form a composite photosensitive layer, thereby solving the technical problem that flexible photodetectors in the prior art are difficult to balance mechanical recovery ability and broadband infrared response performance.

[0005] To achieve the above-mentioned object and other related objects, the present invention provides a flexible photodetector with broadband infrared response. The flexible photodetector with broadband infrared response includes: a substrate, a photosensitive layer and an electrode.

[0006] Among them, the substrate is a flexible substrate; the photosensitive layer is arranged on the substrate, and the photosensitive layer is a thin film formed by a blend of P-type material and N-type material; the electrode is arranged on the photosensitive layer; and at least one of the P-type material and the N-type material has a photoelectric response to infrared band light.

[0007] In one example of the present invention, the N-type material is a transition metal sulfide, and the P-type material is stannous sulfide; wherein the transition metal element in the transition metal sulfide is any one or more of molybdenum, tungsten, niobium, rhenium, and titanium, and the chalcogen element in the transition metal sulfide is any one or more of sulfur, selenium, and tellurium.

[0008] In an example of the present invention, the transition metal sulfide is molybdenum disulfide.

[0009] In an example of the present invention, the photosensitive layer has a photoelectric response to light with a wavelength of 470nm to 1550nm.

[0010] In one example of the present invention, the photosensitive layer includes a bulk heterojunction structure or a hybrid planar bulk heterojunction structure, wherein the bulk heterojunction structure or the hybrid planar bulk heterojunction structure is a composite of P-type material and N-type material through charge transfer.

[0011] In one example of the present invention, a charge transport layer is further provided between the substrate and the photosensitive layer, and the charge transport layer is a hole transport layer or an electron transport layer.

[0012] In an example of the present invention, a channel semiconductor layer is further provided between the charge transport layer and the substrate.

[0013] In an example of the present invention, the photosensitive layer is a thin film formed by mixing the P-type material and the N-type material and depositing them on the substrate by dual-target magnetron sputtering.

[0014] In an example of the present invention, the flexible substrate is mica or at least one of high molecular polymers PET, PEN, PI, PE, Parylene, PES and PDMS.

[0015] In an example of the present invention, the electrode is an interdigitated electrode, a counter electrode or a lead electrode.

[0016] The flexible photodetector with broadband infrared response in the present invention makes up for the shortcomings of the performance of a single material by blending P-type material and N-type material on a flexible substrate to form a composite photosensitive layer, so that the flexible photodetector has both good mechanical recovery ability and wide infrared response performance, ensuring that the flexible photodetector can still maintain a stable and efficient photoelectric response to infrared band lasers after multiple bending and deformation. The intensity, response speed, responsivity and detection rate of the photocurrent generated by the infrared band laser during multiple bending processes are guaranteed to be stable and maintained at a high level. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a three-dimensional device of a flexible photodetector with broadband infrared response in the present invention;

[0019] Figure 2 It is a schematic diagram of the structure of a flexible photoelectric detector with broadband infrared response in one embodiment of the present invention;

[0020] Figure 3 This is a data diagram of the scanning electron microscope test of the MoS2 / SnS mixed film in the present invention;

[0021] Figure 4 The dispersion spectrum of the MoS2 / SnS mixed film tested by transmission electron microscopy in the present invention;

[0022] Figure 5 The light absorption test results of the MoS2 / SnS mixed film, the intrinsic MoS2 film and the SnS film in the present invention are shown in FIG.

[0023] Figure 6 Schematic diagram of the photocurrent test results of the MoS2 / SnS hybrid photodetector of the present invention under illumination with a bias voltage of 1V (λ=473nm, P=1.2mW);

[0024] Figure 7 Schematic diagram of the photocurrent test results of the MoS2 / SnS hybrid photodetector of the present invention at different incident laser wavelengths (λ=808nm, 980nm, 1550nm);

[0025] Figure 8 Schematic diagram of the response time of intrinsic MoS2, intrinsic SnS and MoS2 / SnS hybrid photodetectors under illumination with a bias voltage of 1 V (λ = 808 nm, P = 54 mW);

[0026] Fig. 9 A comparison diagram of the responsivity and specific detectivity of the photodetector with the photosensitive layer being a MoS2 / SnS mixture, intrinsic MoS2 and intrinsic SnS under illumination with a bias voltage of 1V (λ=808nm, P=54mW) in the present invention;

[0027] Fig.10 This is a graph showing the photoelectric performance changes of the flexible photoelectric detector of the present invention at different bending radii;

[0028] Fig.11 A comparison chart of the response time of the flexible photodetector in the present invention under different bending cycles;

[0029] Fig.12 This is a comparison chart of the responsivity and specific detection rate of the flexible photodetector in the present invention under different bending cycles.

[0030] Component number description

[0031] 1. Substrate; 2. Photosensitive layer; 3. Electrode; 4. Charge transfer layer; 5. Channel semiconductor layer. DETAILED DESCRIPTION

[0032] The following is an explanation of the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers.

[0033] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" etc. used in this specification are only for the convenience of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0034] See also Figure 1 The present invention provides a flexible photodetector with broadband infrared response. By blending P-type material and N-type material on a flexible substrate to form a composite photosensitive layer, the shortcomings of the performance of a single material can be compensated, thereby solving the technical problem in the prior art that flexible photodetectors are difficult to balance mechanical recovery ability and broadband infrared response performance.

[0035] See also Figure 1 The above-mentioned flexible photodetector with broadband infrared response includes a substrate 1, a photosensitive layer 2 and an electrode 3.

[0036] See also Figure 1 The substrate 1 is a flexible substrate, which is arranged at the bottom of the flexible photodetector. The photosensitive layer 2 is arranged on the substrate 1 as a functional layer of photoelectric response. The electrode 3 is arranged on the photosensitive layer 2, and the electrode 3 is used to derive the current generated by the photosensitive layer 2 in response to the light in the detection band. It should be noted that the arrangement form of the electrode 3 on the photosensitive layer 2 is not limited, and the electrode 3 can be arranged on the photosensitive layer 2 in various forms such as interdigitated electrodes, counter electrodes or external lead electrodes.

[0037] The photosensitive layer 2 is a thin film formed by a blend of a P-type material and an N-type material, and the P-type material and / or the N-type material of the photosensitive layer 2 has a photoelectric response to infrared light. For example, in an optional embodiment, only the P-type material in the photosensitive layer 2 of the flexible photodetector has a photoelectric response to infrared light, and the N-type material in the photosensitive layer 2 is mixed with the P-type material to compensate for the performance defects of the P-type material; in another optional embodiment, only the N-type material in the photosensitive layer 2 of the flexible photodetector has a photoelectric response to infrared light, and the P-type material in the photosensitive layer 2 is mixed with the N-type material to compensate for the performance defects of the N-type material; in yet another optional embodiment, the P-type material and the N-type material in the photosensitive layer 2 of the flexible photodetector have a photoelectric response to infrared light at the same time, and compensate for the performance defects of each other through blending.

[0038] In addition, it should be noted that the material used for the flexible substrate is not limited, and the flexible substrate can be mica or at least one of high molecular polymers PET, PEN, PI, PE, Parylene, PES and PDMS. Among them, in one embodiment of the present invention, the material used for the flexible substrate is PET (polyethylene terephthalate). This is because the organic polymer material PET has the characteristics of high temperature resistance (long-term working temperature range can be -200 ~ 300 ° C), high insulation, non-toxicity, etc., and can be prepared by a low-cost spinning process to produce a film substrate 1 with adjustable thickness, and its thickness can be controlled at the order of several microns, thereby significantly reducing the thickness of the entire flexible photodetector, which is conducive to obtaining an ultra-thin, flexible and stretchable flexible photodetector.

[0039] In the present invention, the photosensitive layer 2 is a thin film formed by a blend of a P-type material and an N-type material, and the P-type material and the N-type material are mixed and deposited on the substrate 1 by dual-target magnetron sputtering to form a mixed film of an N-type material / P-type material. Among them, the thin film formed by the blend of the N-type material and the P-type material can make up for the performance defects of each other, and the light response band of the photosensitive layer 2 is broadened by combining the light absorption bands of the N-type material and the P-type material and introducing the defects formed by the composite of the P-type material and the N-type material, thereby significantly improving the wavelength and intensity detection range, flexible stretchability and photoelectric response performance of the flexible photodetector.

[0040] The photosensitive layer 2 includes a bulk heterojunction structure or a mixed planar bulk heterojunction structure of N-type material / P-type material, and the bulk heterojunction structure or the mixed planar bulk heterojunction structure is formed by charge transfer between P-type material and N-type material. When the photosensitive layer 2 performs a photoelectric response, the bulk heterojunction structure or the mixed planar bulk heterojunction structure can significantly inhibit the selective capture of electrons by the N-type material and promote the transfer of holes in the P-type material, thereby improving the transmission of photogenerated carriers in the photosensitive layer 2, so that the light absorption of the hybrid film is enhanced, and under the synergistic effect of multiple effects, the performance enhancements such as responsiveness, detection rate, and response speed are obtained.

[0041] In one embodiment of the present invention, the N-type material in the photosensitive layer is selected from transition metal sulfide (MX2). Transition metal sulfide has excellent photoelectric properties, such as high absorbance, rapid generation and migration of carriers, and its band gap covers the visible light to near-infrared light band, and is a high-quality infrared broadband photoelectric detection material. In addition, when transition metal sulfide is a two-dimensional material in the form of a thin film, it has the characteristics of strong covalent intra-layer bonds and weak van der Waals inter-layer bonds. The covalent bond can withstand much higher strain (up to 40%) than the ionic bond body form (≈18%), which enables the two-dimensional transition metal sulfide to withstand more than 10% deformation before breaking, while the fracture value of a typical bulk semiconductor is usually less than 1%. In comparison, the two-dimensional transition metal sulfide has excellent mechanical properties in flexible photodetectors. However, in the prior art, flexible photodetectors using intrinsic transition metal sulfides introduce impurities and generate non-intrinsic scattering sources during the physical contact between the transition metal sulfides and the outside world, thereby reducing the mean free path of carriers. This greatly reduces the carrier mobility of the flexible photodetector and affects other photoelectric properties such as photocurrent intensity, response speed, responsivity and detection.

[0042] However, the inventors found that although transition metal sulfide films have excellent photoelectric and mechanical properties, when used as photosensitive materials for photodetectors on flexible substrates, their photoelectric properties are easily attenuated after multiple strain bending. Taking molybdenum disulfide (MoS2) as an example, MoS2 is an N-type semiconductor material with an indirect band gap, and its own carrier mobility is as high as 480cm 2 V -1 s -1 Due to its excellent mechanical elasticity with an elongation of 11%, MoS2 can be reduced to atomic thickness, which greatly facilitates the design and construction of bending, curling and folding. In theory, it should be a high-quality material for flexible photodetectors. However, the carrier mobility of MoS2 as a photosensitive layer on a flexible substrate is only in the range of 4.7 to 45 cm 2 V -1 s -1Compared with its high carrier mobility on SiO2 substrate, it is reduced by more than ten times. The above phenomenon should be due to the introduction of impurities in physical contact and the generation of non-intrinsic scattering sources, which reduces the mean free path of carriers and greatly attenuates the photoelectric performance.

[0043] Therefore, tin sulfide (SnS) is selected as the P-type material in the photosensitive layer to improve the performance defect of transition metal sulfides, that is, poor transport of photogenerated carriers on flexible substrates. The selection of stannous sulfide as the P-type material in the photosensitive layer has the following advantages and functions: i. Stannous sulfide has a wrinkled structure similar to that of black phosphorus. Mixing with transition metal sulfides can reduce the physical contact between the transition metal sulfides in the photosensitive layer and the outside world during bending, avoid the introduction of impurities to produce non-intrinsic scattering sources, and thus stabilize the photoelectric properties of the photosensitive layer during stretching and bending; ii. Stannous sulfide is an excellent photoelectric detection material with a band gap covering the deep ultraviolet to near-infrared band (280-850nm). Mixing with transition metal sulfides to form a photosensitive layer can broaden the response band of the flexible photodetector; iii. Stannous sulfide is a natural P-type material that can be obtained without a doping process, and it is easy to transfer charges between transition metal sulfides in the photosensitive layer to form a bulk heterojunction structure or a mixed planar bulk heterojunction structure, thereby improving the photogenerated carrier mobility of the photosensitive layer, and achieving enhanced performance such as responsiveness, detection rate, and response speed.

[0044] It should be noted that the chemical formula of the two-dimensional transition metal sulfide is MX2, where M refers to a transition metal element (for example, molybdenum, tungsten, niobium, rhenium, titanium), and X refers to a chalcogen element (for example, sulfur, selenium, tellurium); the transition metal element in the above-mentioned two-dimensional transition metal sulfide is any one or more of molybdenum, tungsten, niobium, rhenium, and titanium, and the chalcogen element in the two-dimensional transition metal sulfide is any one or more of sulfur, selenium, and tellurium.

[0045] In an example of this embodiment, the photosensitive layer of the flexible photodetector is a thin film formed by a mixture of a P-type material tin sulfide (SnS) and an N-type material molybdenum disulfide (MoS2), wherein the SnS and MoS2 are deposited and mixed on a substrate by radio frequency magnetron sputtering technology to form a MoS2 / SnS mixed film, wherein during the deposition and mixing process of MoS2 and SnS, charge transfer can be used to compound in the photosensitive layer to form a MoS2 / SnS bulk heterojunction or a mixed planar bulk heterojunction structure. Figure 3 As shown in the scanning electron microscope test results, the surface of the MoS2 / SnS mixed film of the photosensitive layer in the present invention is smooth and uniform, and has high quality.

[0046] It should be noted that the mixing ratio of SnS and MoS2 in the photosensitive layer is not limited and can be any ratio that can be deposited and mixed on the substrate. In an optional example, the mixing ratio of SnS and MoS2 in the photosensitive layer is 2:1, wherein the proportion of each element in the MoS2 / SnS mixed film is Figure 4 As shown in the dispersion spectrum, specifically, Sn: 38.35%, Mo: 20.64%, S: 41.01%.

[0047] See also Figure 5 In this embodiment, the MoS2 / SnS mixed film in the photosensitive layer has a photoelectric response to light with a wavelength of 470nm to 1550nm, and Figure 5 It can be seen that the MoS2 / SnS mixed film has an absorption effect in the wavelength range of 470nm to 1550nm, and the comparison of the curves in the figure shows that the absorbance of the MoS2 / SnS mixed film is higher than that of the intrinsic MoS2 film in the same response band, and the absorbance of the MoS2 / SnS mixed film in the 470nm to 800nm ​​band is much higher than that of both the intrinsic MoS2 film and the intrinsic SnS film.

[0048] When specifically applied to a flexible photodetector, the flexible photodetector also has an obvious photoelectric response in the absorption band of the MoS2 / SnS mixed film, for example Figure 6 and Figure 7 As shown, the MoS2 / SnS hybrid photodetector generates significant photocurrent under the bias voltage of 1V and laser illumination with wavelengths of 473nm, 808nm, 980nm and 1550nm respectively.

[0049] Moreover, the MoS2 / SnS hybrid photodetector described in this embodiment has significantly improved photoelectric performance in all aspects compared to the intrinsic MoS2 photodetector, for example, the response speed, responsivity and detection rate of the photodetector in response to light signals. It should be noted that in the present invention, the MoS2 / SnS hybrid photodetector refers to a flexible photodetector using a MoS2 / SnS hybrid film as a photosensitive layer, and the intrinsic MoS2 photodetector and the intrinsic SnS photodetector refer to flexible photodetectors using an intrinsic MoS2 film and an intrinsic SnS film as photosensitive layers, respectively.

[0050] For example, in terms of the response speed of the photodetector, the response speed of the MoS2 / SnS hybrid photodetector in this embodiment is several times higher than that of the intrinsic MoS2 photodetector. The response speed of the detector is mainly measured by the response time. The shorter the detector response time, the faster the response speed. The response time includes the rise time and decay time of the photocurrent. The rise time (τ r) is the time taken for the intensity of the current signal generated by the detector in response to light to rise from 10% to 90%, and the decay time (τ d ) is the time taken for the current signal intensity in the detector to decay from 90% to 10%. Figure 8 As shown in the figure, the response data of the single photocurrent generated by the flexible photodetectors of intrinsic MoS2, intrinsic SnS and MoS2 / SnS mixed films under the same illumination are shown. The dark marked area in the figure represents the length of the detector response time. Figure 8 It can be seen that the MoS2 / SnS hybrid photodetector significantly improves the response speed of the intrinsic MoS2 film on the photodetector by mixing SnS, so that the response time of the MoS2 / SnS hybrid photodetector is shortened by 4 times compared with the intrinsic MoS2 photodetector, greatly improving the response speed of the flexible detector.

[0051] In terms of the photoelectric performance of the photodetector, the MoS2 / SnS hybrid photodetector in this embodiment has a high responsivity (R λ ) and detection rate (D * ) are also significantly higher than intrinsic MoS2 photodetectors and intrinsic SnS photodetectors in terms of two important parameters used to evaluate photodetection performance. λ It can be expressed as R λ =I ph / P, where I ph =I illumination -I dark is the photocurrent, I illumination (I dark ) is the current generated by the photodetector when there is (or is not) light, P is the incident laser power, R λ is the measured photoresponsivity in AW -1 Unit: detection rate D * Expressed as D*=R λ ×(A / 2qI dark ) 1 / 2 , where q is the absolute value of the electron charge (1.6×10 -19 C), A is the effective area of ​​the detector, in cm 2 and D * In cm Hz 1 / 2 W -1 (Jones) is the detection rate measured in units; the above responsivity R λ and detection rate D * The higher the value, the stronger the photoelectric performance of the photodetector. Fig. 9 As shown in Figure 2, under near-infrared laser irradiation conditions (λ = 808nm, V = 1V and P = 54mW), the responsivity R of the MoS2 / SnS hybrid photodetector λand detection rate D * They are 1128 times and 30 times that of intrinsic MoS2 photodetector respectively.

[0052] In addition, the MoS2 / SnS hybrid photodetector has both mechanical recovery capability and broadband infrared response performance compared to the intrinsic MoS2 photodetector. Fig.10 As shown, the MoS2 / SnS hybrid photodetector can be bent to a minimum radius of 3mm, and the photocurrent of the MoS2 / SnS hybrid photodetector in the on / off state only fluctuates slightly within the bending radius range of 3mm to 12mm, which means that different degrees of deformation will not significantly inhibit the light response characteristics of the MoS2 / SnS hybrid photodetector. Fig.11 and Fig.12 It can be seen that the photoelectric characteristics (response time, responsivity R λ and detection rate D * ) Even after 2000 consecutive bends, it remains within a stable range without obvious attenuation.

[0053] At the same time, the MoS2 / SnS hybrid photodetector also has extremely strong durability. After being exposed to air for 120 days in a packaged state, the photocurrent only decreases by 7%.

[0054] See also Figure 2 In one embodiment of the present invention, a charge transport layer 4 is further provided between the substrate 1 and the photosensitive layer 2, and the charge transport layer 4 is a hole transport layer or an electron transport layer. The hole transport layer or the electron transport layer is provided to transport excess electrons or holes in the photosensitive layer 2. For example, when the proportion of N-type material in the photosensitive layer 2 is much higher than that of P-type material, the charge transport layer 4 is provided as an electron transport layer, and when the photosensitive layer 2 responds to a light signal, the electron transport layer uses a bulk heterojunction structure or a mixed planar bulk heterojunction structure as a bridge to transport excess electrons in the N-type material to the substrate 1, thereby increasing the carrier mobility of the flexible photodetector; or, when the proportion of P-type material in the photosensitive layer 2 is much higher than that of N-type material, the charge transport layer 4 is provided as a hole transport layer, and when the photosensitive layer 2 responds to a light signal, the hole transport layer uses a bulk heterojunction structure or a mixed planar bulk heterojunction structure as a bridge to absorb excess holes in the P-type material, and transport the absorbed holes to the substrate 1, thereby increasing the carrier mobility of the flexible photodetector.

[0055] Further, if Figure 2 As shown, in this embodiment, a channel semiconductor layer 5 may be further provided between the charge transport layer 4 and the substrate 1 to further enhance the ability of the charge transport layer 4 to transport excess electrons or holes.

[0056] The flexible photodetector with broadband infrared response in the present invention makes up for the shortcomings of the performance of a single material by blending P-type material and N-type material on a flexible substrate to form a composite photosensitive layer, so that the flexible photodetector has both good mechanical recovery ability and wide infrared response performance, ensuring that the flexible photodetector can still maintain a stable and efficient photoelectric response to infrared band lasers after multiple bending and deformation. The intensity, response speed, responsivity and detection rate of the photocurrent generated by the infrared band laser during multiple bending processes are guaranteed to be stable and maintained at a high level. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A flexible photodetector with broadband infrared response, characterized in that: include: a substrate, which is a flexible substrate; A photosensitive layer, which is disposed on the substrate, and is a thin film formed by sputtering a P-type material and an N-type material; an electrode disposed on the photosensitive layer; Among them, the photosensitive layer includes a bulk heterojunction structure or a mixed planar bulk heterojunction structure, and the bulk heterojunction structure or the mixed planar bulk heterojunction structure is a composite of charge transfer between the P-type material and the N-type material. The P-type material and / or the N-type material has a photoelectric response to infrared light. The P-type material is stannous sulfide, and the N-type material is molybdenum disulfide.

2. The flexible photodetector with broadband infrared response according to claim 1, characterized in that: The photosensitive layer has a photoelectric response to light with a wavelength of 470nm to 1550nm.

3. The flexible photodetector with broadband infrared response according to claim 1, characterized in that: A charge transport layer is further provided between the substrate and the photosensitive layer, and the charge transport layer is a hole transport layer or an electron transport layer.

4. The flexible photodetector with broadband infrared response according to claim 3, characterized in that: A channel semiconductor layer is also provided between the charge transport layer and the substrate.

5. The flexible photodetector with broadband infrared response according to claim 1, characterized in that: The photosensitive layer is a thin film formed by mixing the P-type material and the N-type material and depositing them on the substrate through dual-target magnetron sputtering.

6. The flexible photodetector with broadband infrared response according to claim 1, characterized in that: The flexible substrate is mica or at least one of high molecular polymers PET, PEN, PI, PE, Parylene, PES and PDMS.

7. The flexible photodetector with broadband infrared response according to claim 1, characterized in that: The electrodes are interdigitated electrodes, counter electrodes or lead electrodes.

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