Organic / inorganic heterojunction, preparation method thereof and self-driven photodetector
Patent Information
- Application Number
- CN202510521704.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2026-10-27
AI Technical Summary
[0004]本发明要解决现有技术中有机/无机结合光电探测器的界面质量和稳定性及响应速度不理想的技术问题，提供一种有机/无机异质结及其制备方法与自驱动光电探测器
[0020]本发明的有机/无机异质结为InSe/IEICO-4F异质结光敏层(即感光层)，InSe与IEICO-4F的能带匹配(type-II异质结)在界面处形成强内建电场，结合垂直堆叠架构，可缩短载流子传输路径，优化电荷提取效率。由该光敏层制备的自驱动光电探测器可以实现高灵敏度、低暗电流、良好的响应速度。
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Figure CN122995389A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor materials technology, specifically relating to an organic / inorganic heterojunction, its preparation method, and a self-driven photodetector. Background Technology
[0002] Near-infrared (NIR) photodetectors play a crucial role in numerous applications, including communications, remote sensing, medical imaging, and environmental monitoring. Detectors in the near-infrared spectral region possess excellent penetrating power, effectively penetrating the atmosphere, human tissue, and other substances, thus demonstrating significant potential in areas such as security monitoring, environmental surveillance, and biomedical imaging.
[0003] In recent years, inorganic materials (such as the III-VI group semiconductor material InSe) and organic materials (such as IEICO-4F and Y6 derivatives) have attracted much attention in the field of near-infrared detection. Combining inorganic and organic materials to form organic / inorganic heterojunction photodetectors has become an important research direction in recent years. By combining the excellent electrical properties of inorganic materials with the flexibility and tunability of organic materials, it is hoped that the limitations of single materials can be overcome and the overall performance of photodetectors can be optimized. However, such organic / inorganic combined detectors also face certain challenges. The most significant issues lie in the quality and stability of the heterojunction interface and the compatibility between the two materials. Furthermore, although organic / inorganic photodetectors exhibit good overall performance, their rise / fall times are generally still in the millisecond range, limiting their performance in high-speed applications. Therefore, improving response speed, optimizing interface characteristics, and enhancing long-term stability are key issues that need to be addressed in current organic / inorganic combined photodetectors. Summary of the Invention
[0004] This invention addresses the technical problems of unsatisfactory interface quality, stability, and response speed in existing organic / inorganic hybrid photodetectors by providing an organic / inorganic heterojunction, its fabrication method, and a self-driven photodetector. The organic / inorganic heterojunction of this invention is an InSe / IEICO-4F heterojunction photosensitive layer. The band matching between InSe and IEICO-4F (type-II heterojunction) creates a strong built-in electric field at the interface. Combined with a vertical stacking architecture, this shortens the carrier transport path and optimizes charge extraction efficiency. The self-driven photodetector fabricated from this photosensitive layer achieves high sensitivity, low dark current, and good response speed.
[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:
[0006] An organic / inorganic heterostructure includes a substrate and an InSe nanosheet and an IEICO-4F organic thin film sequentially disposed on the substrate.
[0007] In the above technical solution, preferably, the thickness of the InSe nanosheet is 10nm to 50nm, and the thickness of the IEICO-4F organic film is 50nm to 70nm.
[0008] In the above technical solution, it is further preferred that the InSe nanosheets have a thickness of 20 nm and the IEICO-4F organic film has a thickness of 60 nm.
[0009] In the above technical solution, preferably, the substrate is an ITO substrate.
[0010] A method for preparing an organic / inorganic heterojunction includes the following steps:
[0011] Step 1: Mechanically exfoliate the InSe crystals until the material is mostly transparent. Then, use polydimethylsiloxane (PDMS) as a transfer medium to transfer the exfoliated InSe nanosheets onto the target substrate.
[0012] Step 2: Plasma cleaning is performed on the substrate with InSe nanosheets. Then, IEICO-4F is dissolved in an organic solvent, and 1-chloronaphthalene is added to the solution. The resulting mixture is spin-coated onto the substrate with InSe nanosheets to obtain an IEICO-4F organic film. Annealing is then performed to obtain an organic / inorganic heterojunction photosensitive layer.
[0013] In the above technical solution, the specific steps for transferring the stripped InSe nanosheets onto the target substrate (1) in step 1 are as follows:
[0014] After the PDMS with InSe nanosheets is brought into contact with the ultrasonically cleaned substrate, it is heated on a heating stage at 120°C to reduce the viscosity of the PDMS, thereby allowing the InSe nanosheets to detach from the PDMS and adhere firmly to the substrate surface.
[0015] In the above technical solution, in step 2, the plasma cleaning time is 5 minutes.
[0016] In the above technical solution, in step 2, IEICO-4F is dissolved in the organic solvent chloroform at a concentration of 8 mg / mL, and 0.5 wt% of 1-chloronaphthalene is added to it. The mixture is stirred for more than 10 hours at a temperature of 35-40°C and a stirring speed of 500-600 rpm to make it uniform and obtain a mixed solution.
[0017] In the above technical solution, in step 2, a spin coater is used for coating. The spin coater speed is set to 6000 rpm and the acceleration is set to 6000 rpm / s. The annealing conditions are: annealing at 80℃ for 5 minutes.
[0018] A self-driven photodetector based on an organic / inorganic heterojunction as the photosensitive layer, wherein an Au block electrode is further disposed on the photosensitive layer.
[0019] The beneficial effects of this invention are:
[0020] The organic / inorganic heterojunction of this invention is an InSe / IEICO-4F heterojunction photosensitive layer (i.e., photosensitive layer). The band matching of InSe and IEICO-4F (type-II heterojunction) creates a strong built-in electric field at the interface. Combined with a vertical stacking architecture, this shortens the carrier transport path and optimizes charge extraction efficiency. The self-driven photodetector fabricated from this photosensitive layer can achieve high sensitivity, low dark current, and good response speed.
[0021] The fabrication process of the organic / inorganic heterojunction and detector of the present invention is simple and easy to implement.
[0022] Experimental results show that the IV characteristic curve of the self-driven photodetector of this invention exhibits significant rectification characteristics. Under an 808nm optical signal, the device has a good response to the optical signal at 0V bias, with a brightness-to-dark current ratio of 10. 3 The photoelectric performance is improved, with both mobility and photoelectric properties exhibiting high levels. Response time testing of the detector shows rise / fall times on the order of microseconds, demonstrating excellent response speed. Attached Figure Description
[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0024] Figure 1 This is a schematic diagram of the device structure of a self-driven photodetector based on the inorganic / organic heterojunction as the photosensitive layer of the present invention.
[0025] Figure 2 This is an AFM scan image of the step height of the InSe nanosheets prepared in Example 1.
[0026] Figure 3 The image shown is a cross-sectional image of the IEICO-4F organic thin film prepared in Example 1 using a scanning electron microscope.
[0027] Figure 4 The graph shows the photocurrent switching characteristics of the near-infrared self-driven photodetector prepared in Example 1.
[0028] Figure 5 This is an AFM scan image of the step height of the InSe nanosheets prepared in Example 2.
[0029] Figure 6 The image shows the IV characteristic curve of the near-infrared self-driven photodetector prepared in Example 2.
[0030] Figure 7 The graph shows the photocurrent switching characteristics of the near-infrared self-driven photodetector prepared in Example 2.
[0031] Figure 8 The graph shows the light response time test data of the near-infrared self-driven photodetector prepared in Example 2.
[0032] Figure 9 This is an AFM scan image of the step height of the InSe nanosheets prepared in Example 3.
[0033] Figure 10 The graph shows the photocurrent switching characteristics of the near-infrared self-driven photodetector prepared in Example 3.
[0034] The reference numerals in the figure are:
[0035] 1-ITO substrate, 2-InSe nanosheets, 3-IEICO-4F organic thin film, 4-Au cubic electrode. Detailed Implementation
[0036] The inventive concept of this invention is to address key challenges in current organic / inorganic hybrid photodetectors, namely improving response speed, optimizing interface characteristics, and enhancing long-term stability. InSe crystals, a group III-VI monochalcogenide, possess excellent electron mobility and a relatively low effective electron mass, demonstrating potential for high photoelectric conversion efficiency. The organic material IEICO-4F exhibits significant charge transfer capabilities, efficiently converting light energy into electrical energy and displaying excellent absorption characteristics in the visible to near-infrared bands. Furthermore, the band matching (type-II heterojunction) between InSe and IEICO-4F creates a strong built-in electric field at the interface. Combined with a vertical stacking architecture, this shortens carrier transport paths and optimizes charge extraction efficiency. Therefore, through interface engineering, a near-infrared photodetector combining organic and inorganic technologies can be realized, characterized by high sensitivity, low dark current, and simple fabrication processes.
[0037] This invention provides an organic / inorganic heterojunction, comprising a substrate 1, and InSe nanosheets 2 and an IEICO-4F organic thin film 3 sequentially disposed on the substrate 1. Preferably, the thickness of the InSe nanosheets 2 is 10 nm to 50 nm, and the thickness of the IEICO-4F organic thin film 3 is 50 nm to 70 nm; more preferably, the thickness of the InSe nanosheets 2 is 20 nm, and the thickness of the IEICO-4F organic thin film 3 is 60 nm. Preferably, the substrate 1 is an ITO substrate.
[0038] This invention also provides a self-driven photodetector based on an organic / inorganic heterojunction as the photosensitive layer, wherein the photosensitive layer is further provided with an Au block electrode 4. A schematic diagram of the self-driven photodetector structure is shown below. Figure 1 .
[0039] This invention provides a method for preparing an organic / inorganic heterojunction, comprising the following steps:
[0040] InSe crystals were mechanically exfoliated using 3M tape, repeated until the material became mostly transparent. Then, polydimethylsiloxane (PDMS) was used as a transfer medium to transfer the exfoliated InSe nanosheets 2 onto a target substrate 1, preferably an ITO substrate. After the PDMS was brought into contact with the ultrasonically cleaned ITO substrate 1, it was heated on a 120°C heating stage to reduce the PDMS's viscosity, thereby allowing the InSe nanosheets 2 to detach from the PDMS and firmly adhere to the surface of the ITO substrate 1. The thickness of the InSe nanosheets 2 was preferably 20 nm. The ITO substrate 1 with the InSe nanosheets 2 adhered was then subjected to plasma cleaning for 5 min to remove residual adhesive and make the substrate 1 hydrophilic. IEICO-4F was dissolved in the organic solvent chloroform at a concentration of 8 mg / mL. To reduce roughness and improve electron mobility, 0.5 wt% 1-chloronaphthalene was added to the solution. The mixture was stirred for at least 10 h at a temperature of 35–40°C and a stirring speed of 500–600 rpm to ensure homogeneity. Spin coating was performed using a spin coater with a spin speed of 6000 rpm and an acceleration of 6000 rpm / s. The resulting mixture was spin-coated onto an ITO substrate 1 with InSe nanosheets 2 attached in a glove box filled with inert gas. The thickness of the IEICO-4F organic thin film 3 was preferably 60 nm. The film was then annealed at 80°C for 5 min to obtain an organic heterojunction photosensitive layer.
[0041] The present invention provides a method for fabricating a self-driven photodetector based on an organic / inorganic heterojunction as a photosensitive layer, wherein Au block electrodes 4 are fabricated on the organic / inorganic heterojunction photosensitive layer prepared above by means of thermal evaporation deposition, and a self-driven photodetector with a vertical structure based on the organic / inorganic heterojunction photosensitive layer is fabricated.
[0042] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0043] Example 1:
[0044] The ITO substrate 1 was ultrasonically cleaned sequentially with acetone, alcohol, and deionized water, each step lasting 15 minutes, and then dried with a nitrogen gun. The InSe crystals were mechanically exfoliated using 3M tape, repeated until the material was mostly transparent. Subsequently, polydimethylsiloxane (PDMS) was used as a transfer medium to transfer the exfoliated InSe nanosheets 2 onto the target substrate 1. After the PDMS came into contact with the ITO substrate 1, it was heated on a 120°C heating stage to reduce the PDMS's adhesiveness, thereby allowing the InSe nanosheets 2 to detach from the PDMS and firmly adhere to the surface of the ITO substrate 1. The InSe nanosheets 2 were approximately 12 nm thick (e.g., ...). Figure 2 The substrate 1 with InSe nanosheets 2 was plasma-cleaned for 5 min to remove residual adhesive and make the substrate 1 hydrophilic. After the InSe nanosheets 2 were prepared, the mixture and the substrate 1 with InSe nanosheets 2 were transferred into a glove box filled with inert gas. The spin coater was set to a speed of 6000 rpm, an acceleration of 6000 rpm / s, and a time of 30 s. 30 μL of the mixture was pipetted onto the center of the substrate 1 for spin coating. After coating, it was placed on an annealing station at 80 °C for 5 min. The thickness of the IEICO-4F organic film 3 was approximately 60 nm (e.g., ...). Figure 3 An organic / inorganic heterojunction photosensitive layer was prepared. Au cubic electrodes 4 were fabricated on the photosensitive layer using a thermal evaporation process, thus creating a near-infrared self-driven photodetector with a vertical structure based on the organic / inorganic photosensitive layer. Under an 808nm optical signal, the device exhibited good response to the optical signal at 0V bias (e.g., ...). Figure 4 ).
[0045] Example 2:
[0046] The ITO substrate 1 was ultrasonically cleaned sequentially with acetone, alcohol, and deionized water, each step lasting 15 minutes, and then dried with a nitrogen gun. The InSe crystals were mechanically exfoliated using 3M tape, repeated until the material was mostly transparent. Subsequently, polydimethylsiloxane (PDMS) was used as a transfer medium to transfer the exfoliated InSe nanosheets 2 onto the target substrate 1. After the PDMS came into contact with the ITO substrate 1, it was heated on a 120°C heating stage to reduce the PDMS's adhesiveness, thereby allowing the InSe nanosheets 2 to detach from the PDMS and firmly adhere to the surface of the ITO substrate 1. The thickness of the InSe nanosheets 2 was approximately 20 nm (e.g., ...). Figure 5The substrate 1 with InSe nanosheets 2 was plasma-cleaned for 5 min to remove residual adhesive and make the substrate 1 hydrophilic. After the InSe nanosheets 2 were prepared, the mixture and the substrate 1 with InSe nanosheets 2 were transferred into a glove box filled with inert gas. The spin coater was set to a speed of 6000 rpm, an acceleration of 6000 rpm / s, and a time of 30 s. 30 μL of the mixture was pipetted onto the center of the substrate 1 for spin coating. After coating, it was placed on an annealing station at 80℃ for 5 min. The thickness of the IEICO-4F organic thin film 3 was approximately 60 nm. Au block electrodes 4 were prepared on the heterojunction photosensitive layer using a thermal evaporation process to fabricate a near-infrared self-driven photodetector with a vertical structure based on an organic / inorganic heterojunction photosensitive layer. The IV characteristic curve of this detector showed significant rectification characteristics (e.g., Figure 6 The rectification effect is caused by the difference in potential barrier heights on both sides of the contact between the semiconductor and gold and ITO. Under an 808nm optical signal, the device exhibits good response to the optical signal at 0V bias (e.g., Figure 7 The ratio of light to dark current is 10. 3 The photoelectric properties are improved. This is because when the InSe nanosheet 2 is relatively thin, the mobility increases with increasing thickness, exhibiting excellent electrical properties at thinner thicknesses. When the thickness reaches approximately 20 nm, both the mobility and photoelectric properties show high levels. Response time testing of Example 2 showed that the rise / fall times were in the microsecond range, indicating good response speed (e.g., ...). Figure 8 ).
[0047] Example 3:
[0048] The ITO substrate 1 was ultrasonically cleaned sequentially with acetone, alcohol, and deionized water, each step lasting 15 minutes, and then dried with a nitrogen gun. The InSe crystals were mechanically exfoliated using 3M tape, repeated until the material was mostly transparent. Subsequently, polydimethylsiloxane (PDMS) was used as a transfer medium to transfer the exfoliated InSe nanosheets 2 onto the target substrate 1. After the PDMS came into contact with the ITO substrate 1, it was heated on a 120°C heating stage to reduce the PDMS's adhesiveness, thereby allowing the InSe nanosheets 2 to detach from the PDMS and firmly adhere to the surface of the ITO substrate 1. The thickness of the InSe nanosheets 2 was approximately 49 nm (e.g., ...). Figure 9The substrate 1 with InSe nanosheets 2 was plasma-cleaned for 5 min to remove residual adhesive and make the substrate 1 hydrophilic. After the InSe nanosheets 2 were prepared, the mixture and the substrate 1 with InSe nanosheets 2 were transferred into a glove box filled with inert gas. The spin coater was set to a speed of 6000 rpm, an acceleration of 6000 rpm / s, and a time of 30 s. 30 μL of the mixture was pipetted onto the center of the substrate 1 for spin coating. After coating, it was placed on an annealing station at 80℃ for 5 min. The thickness of the IEICO-4F organic thin film 3 was approximately 60 nm. Au block electrodes 4 were fabricated on the heterojunction photosensitive layer using a thermal evaporation process to create a near-infrared self-driven photodetector with a vertical structure based on an organic / inorganic heterojunction. Under an 808 nm light signal, the device showed good response to the light signal at 0 V bias (e.g., Figure 10 The photoelectric performance deteriorates. This is because when the InSe nanosheet 2 is thicker, its carrier mobility decreases with increasing thickness. This is because thicker InSe nanosheets 2 have a larger intermolecular interaction distance, and the Coulomb scattering effect of impurity molecules adsorbed on the surface on the carriers is relatively weaker. With further increases in thickness, the interlayer resistance increases significantly and becomes dominant. A larger interlayer resistance leads to an increase in contact resistance, thereby reducing the carrier transport efficiency. Therefore, the mobility decreases with increasing thickness, and the photoelectric performance also decreases accordingly.
[0049] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. An organic / inorganic heterostructure, characterized in that, It includes a substrate (1), and InSe nanosheets (2) and IEICO-4F organic thin film (3) sequentially disposed on the substrate (1).
2. The organic / inorganic heterojunction according to claim 1, characterized in that, The InSe nanosheets (2) have a thickness of 10 nm to 50 nm, and the IEICO-4F organic film (3) has a thickness of 50 nm to 70 nm.
3. The organic / inorganic heterojunction according to claim 1, characterized in that, The InSe nanosheets (2) have a thickness of 20 nm, and the IEICO-4F organic film (3) has a thickness of 60 nm.
4. The organic / inorganic heterojunction according to claim 1, characterized in that, The substrate (1) is an ITO substrate.
5. A method for preparing an organic / inorganic heterojunction according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Mechanically exfoliate the InSe crystal until the material is mostly transparent. Then, using polydimethylsiloxane (PDMS) as a transfer medium, transfer the exfoliated InSe nanosheets (2) onto the target substrate (1). Step 2: Plasma cleaning is performed on the substrate (1) with InSe nanosheets (2) attached. Then, IEICO-4F is dissolved in an organic solvent and 1-chloronaphthalene is added to the solution. The resulting mixture is spin-coated onto the substrate (1) with InSe nanosheets (2) attached to obtain an IEICO-4F organic film (3). Annealing is performed to obtain an organic / inorganic heterojunction.
6. The method for preparing organic / inorganic heterojunctions according to claim 5, characterized in that, In step 1, the specific steps for transferring the stripped InSe nanosheets (2) onto the target substrate (1) are as follows: After the PDMS with InSe nanosheets (2) attached is brought into contact with the ultrasonically cleaned substrate (1), it is heated on a heating stage at 120°C to reduce the viscosity of the PDMS, thereby allowing the InSe nanosheets (2) to detach from the PDMS and adhere firmly to the surface of the substrate (1).
7. In the method for preparing organic / inorganic heterojunctions according to claim 5, the plasma cleaning time in step 2 is 5 min.
8. In the method for preparing the organic / inorganic heterojunction according to claim 5, in step 2, IEICO-4F is dissolved in the organic solvent chloroform at a concentration of 8 mg / mL, and 0.5 wt% of 1-chloronaphthalene is added thereto. The mixture is stirred for more than 10 hours at a temperature of 35-40°C and a stirring speed of 500-600 rpm to make it uniform and obtain a mixed solution.
9. In the method for preparing organic / inorganic heterojunctions according to claim 5, in step 2, spin coating is performed using a spin coater with a rotation speed of 6000 rpm and an acceleration of 6000 rpm / s; the annealing conditions are: annealing at 80°C for 5 min.
10. A self-driven photodetector based on the organic / inorganic heterojunction as the photosensitive layer according to any one of claims 1-4, wherein the photosensitive layer is further provided with an Au block electrode (4).