A dual-mode photoelectric device with ultraviolet photosynapse and near-infrared photodetection

Abstract

The present invention relates to a photoelectric device that generates electrical energy by converting ultraviolet and near-infrared light. A dual-mode photoelectric device, ultraviolet photosynapse / near-infrared photodetection, is disclosed. This dual-mode device integrates both ultraviolet photosynapse and near-infrared photodetection functions: The ultraviolet photosynapse function is achieved through a heterojunction consisting of a single-layer graphene film and a wide-bandgap perovskite Cs3Cu2I5 film. The Cs3Cu2I5 film is doped with B4PyMPM as an electron-trapping site to enhance electron-trapping capability, thereby improving the performance of the ultraviolet photosynapse device. The near-infrared photodetection function is achieved through a heterojunction consisting of a single-layer graphene film and n-type Ge. The Cs3Cu2I5 film is optimized in thickness to serve as an antireflection layer in the 1550 nm near-infrared band, thereby improving the responsivity, specific detectivity, and other performance characteristics of the near-infrared photodetection device. The device structure and process of the present invention are simple, avoiding the need for expensive instrumentation and equipment, and reducing device manufacturing costs.

Description

Technical Field

[0001] The present invention relates to a photoelectric device that generates electric energy by converting ultraviolet light and near-infrared light, and in particular to an ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device. Background Art

[0002] A photodetector is a photoelectric conversion device that can quickly convert light signals into electrical signals. It has high responsiveness and sensitivity and is widely used in many scientific research and industrial technology fields, such as image sensing, fiber optic communications, photoelectric detection, fire monitoring, biomedical imaging, environmental monitoring, space exploration, and safety detection. However, photodetectors cannot permanently store images or process complex time series data, which limits their application in certain scenarios. Photoelectric synaptic devices are another important type of photoelectric conversion device. These devices are inspired by biological neural synapses and simulate the plasticity of biological synapses to achieve brain-like efficient information processing and storage, thereby enabling the perception, storage, and processing of optical signals.

[0003] The rapid development of emerging artificial intelligence technologies such as robotics and autonomous driving has placed greater demands on the multifunctionality of optoelectronic devices. The goal is to integrate multiple functions, including photodetection, information processing, sensing, storage, and even logic operations, into a single device or compact system. This reduces device size, reduces power consumption, improves efficiency, and enhances intelligence. Currently, multimode optoelectronic devices typically integrate multiple single-function devices into a single system, which inevitably increases system complexity, size, power consumption, and introduces numerous operational inconveniences. Integrating photodetection and neural synaptic functions into a single device to create dual-mode optoelectronic devices will help improve their integration and expand their applications. However, due to the distinct operating mechanisms and significant differences in light response speed between the two devices, achieving both photodetection and neural synaptic functions in a single device is difficult. Furthermore, the limited response band of the photosensitive materials in optoelectronic devices makes integrating photodetection and neural synaptic functions with different response bands into the same device even more challenging.

[0004] Currently, the main approach to developing high-performance UV photoelectric synaptic devices is to use wide-bandgap semiconductor oxides as the photosensitive layer and exploit the persistent photoconductivity induced by the ionization and dissociation of oxygen vacancies in oxide semiconductors to simulate the function of neural synapses. However, the ionization and dissociation processes of oxygen vacancies are difficult to control, making device performance optimization very challenging. Wide-bandgap perovskites have excellent properties such as high UV light absorption coefficient, tunable optical band gap, and low defect density. Constructing heterojunctions based on wide-bandgap perovskites and utilizing their matching energy levels to achieve selective conduction of photogenerated carriers is an effective strategy for preparing high-performance UV photoelectric synaptic devices. However, wide-bandgap perovskites suffer from severe recombination of photogenerated carriers. Photogenerated electrons and holes may be simultaneously injected into the conductive layer, leading to even more severe carrier recombination, resulting in poor device performance and hindering practical applications. In addition, the use of two-dimensional materials / narrow-bandgap semiconductor heterostructures is expected to achieve low-cost, high-performance near-infrared light detection. However, due to the high refractive index and limited light absorption coefficient of narrow-bandgap semiconductors in the near-infrared band, the planar structure of narrow-bandgap semiconductors often has high reflectivity to near-infrared light, making it difficult to further improve device performance. Summary of the Invention

[0005] In order to avoid the shortcomings of the above-mentioned prior art, the present invention provides a dual-mode optoelectronic device of ultraviolet photoelectric synapse / near-infrared photoelectric detection, aiming to construct a Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction, and effectively improve the performance of ultraviolet photoelectric synapse by enhancing the electron capture ability through B4PyMPM doping. At the same time, by optimizing the thickness of the wide bandgap perovskite film, the wide bandgap perovskite film becomes an anti-reflection layer in a specific band, effectively improving the near-infrared photoelectric detection performance such as responsiveness and specific detection rate, thereby obtaining an optoelectronic device with integrated ultraviolet photoelectric synapse and near-infrared photoelectric detection dual functions.

[0006] The present invention adopts the following technical solutions to solve the technical problems:

[0007] The present invention first provides an ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device, which is characterized in that: the dual-mode photoelectric device is provided with a single-layer graphene film on the upper surface of an n-type Ge substrate, and a Cs3Cu2I5-B4PyMPM film is laid on the single-layer graphene film; the n-type Ge substrate and the single-layer graphene film form a heterojunction, and the single-layer graphene film and the Cs3Cu2I5-B4PyMPM film form a heterojunction; the Cs3Cu2I5-B4PyMPM film is obtained by doping the Cs3Cu2I5 film with B4PyMPM (4,6-bis(3,5-di(4-pyridyl)phenyl)-2-methylpyrimidine).

[0008] The dual-mode optoelectronic device can realize the dual functions of ultraviolet photoelectric synapse and near-infrared photoelectric detection, and the implementation method is as follows:

[0009] The heterojunction formed by a Cs3Cu2I5-B4PyMPM film and a single-layer graphene film realizes the ultraviolet photoelectric synaptic function, forming an ultraviolet photoelectric synaptic device. Specifically, by doping the Cs3Cu2I5 film with B4PyMPM, the electron capture capability is enhanced, carrier recombination is reduced, and efficient separation and transmission of photogenerated carriers are achieved. This reduces the drop in photocurrent and increases the duration of photocurrent, thereby improving the performance of the ultraviolet photoelectric synaptic device.

[0010] A near-infrared photodetection device is constructed by forming a heterojunction between an n-type Ge substrate and a single-layer graphene film. The Cs3Cu2I5-B4PyMPM film serves as an antireflection layer, improving the device's responsivity, specific detectivity, and other performance. The thickness of the Cs3Cu2I5-B4PyMPM film can be adjusted to control the wavelength of the antireflection layer in the near-infrared wavelength range. For example, a Cs3Cu2I5-B4PyMPM film with a thickness of 260-280 nm can be used as an antireflection layer in the 1550 nm wavelength range.

[0011] Furthermore, the Cs3Cu2I5-B4PyMPM film is prepared by adding B4PyMPM to a Cs3Cu2I5 perovskite precursor solution containing CsI and CuI, mixing the mixture to obtain a doping solution, and then spin-coating the doping solution onto a target substrate to form a thin film. In the doping solution, the mass of B4PyMPM accounts for 0.05-0.15 wt% of the total mass of CsI and CuI.

[0012] Furthermore, an n-type Ge substrate electrode is provided on the lower surface of the n-type Ge substrate, and a metal electrode is provided on the Cs3Cu2I5-B4PyMPM film.

[0013] To further optimize the performance of the dual-mode optoelectronic device, the following parameters were set: the n-type Ge substrate employed an n-type doped Ge sheet with a resistivity of 0.5-30 Ω / cm. The Cs3Cu2I5-B4PyMPM film had a thickness of 260-280 nm. The n-type Ge substrate electrode was an In-Ga alloy electrode. The metal electrode was a Ni electrode with a thickness of 60-100 nm.

[0014] The method for preparing the ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device of the present invention can be carried out according to the following steps:

[0015] (1) The n-type Ge substrate was ultrasonically cleaned with deionized water, acetone, and alcohol in sequence, and then dried with nitrogen;

[0016] (2) using a graphene wet transfer method to transfer a single-layer graphene film to the upper surface of the n-type Ge substrate, wherein the boundary of the single-layer graphene film does not exceed the boundary of the n-type Ge substrate;

[0017] (3) preparing a perovskite precursor solution containing B4PyMPM, and then spin-coating it on the upper surface of the single-layer graphene film to form a Cs3Cu2I5-B4PyMPM film;

[0018] (4) A metal electrode is provided on the Cs3Cu2I5-B4PyMPM film by using a method such as thermal evaporation; an n-type Ge substrate electrode is provided on the lower surface of the n-type Ge substrate by using a method such as coating or thermal evaporation coating, thereby obtaining a UV photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device based on the Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction.

[0019] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0020] 1. This invention achieves both ultraviolet photosynaptic and near-infrared photodetection functions in a single device by constructing a Cs3Cu2I5-B4PyMPM / graphene / Ge heterostructure. When used as an ultraviolet photosynaptic device, the high UV light absorptivity of wide-bandgap perovskites, combined with the enhanced electron capture capability of B4PyMPM doping, enhances the absorption efficiency of detection light and the separation and transmission efficiency of photogenerated carriers. When used as a near-infrared photodetector, the B4PyMPM-doped wide-bandgap perovskite Cs3Cu2I5 thin film serves as an antireflection layer, significantly improving near-infrared photodetection performance.

[0021] 2. The Cs3Cu2I5-B4PyMPM thin film in the dual-mode optoelectronic device of the present invention can be prepared by spin coating, which has a simple process, avoids expensive instruments and equipment, and reduces the cost of device preparation.

[0022] 3. The dual-mode optoelectronic device of the present invention can operate at a low bias voltage and consume only a small amount of external energy, thereby effectively reducing power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1This is a structural schematic diagram of the ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device based on the Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction of the present invention. The numbers in the figure are: 1 is the n-type Ge substrate electrode; 2 is the n-type Ge substrate; 3 is the single-layer graphene film; 4 is the Cs3Cu2I5-B4PyMPM film; 5 is the metal electrode.

[0024] Figure 2 Schematic diagram of the energy bands of B4PyMPM, Cs3Cu2I5, graphene and n-type Ge.

[0025] Figure 3 The ultraviolet photoelectric synaptic devices of the B4PyMPM-doped and undoped B4PyMPM prepared in Example 1 of the present invention were subjected to a bias voltage of 0.005 V at a wavelength of 265 nm, a pulse time of 1 s, and an intensity of 0.356 mW / cm 2 Time response curve under UV light.

[0026] Figure 4 The ultraviolet photoelectric synaptic devices of the B4PyMPM-doped and undoped B4PyMPM prepared in Example 1 of the present invention were subjected to a bias voltage of 0.005 V at a wavelength of 265 nm, a pulse time of 1 s, and an intensity of 0.356 mW / cm 2 Figure 1 shows the STP response curve (STP stands for short-term plasticity) under ultraviolet light. In the figure, A1 is the excitatory postsynaptic current stimulated by the first light pulse, and A2 is the excitatory postsynaptic current stimulated by the second light pulse.

[0027] Figure 5 The B4PyMPM-doped UV photoelectric synaptic device prepared in Example 1 of the present invention was subjected to UV irradiation at wavelengths of 254 nm, 265 nm, 300 nm, and 365 nm (pulse time of 1 s and intensity of 0.356 mW / cm 2 ) time response curve under .

[0028] Figure 6 The ultraviolet photoelectric synaptic device doped with B4PyMPM prepared in Example 1 of the present invention has a bias voltage of 0.005 V and an intensity of 0.356 mW / cm 2 , 0.767 mW / cm 2 , 1.170 mW / cm 2 , 1.560 mW / cm 2 , 1.920mW / cm 2LTP response curve (LTP stands for long-term plasticity, STP stands for short-term plasticity) under ultraviolet light (the wavelength is 265nm, the pulse time is 1s, and the number of pulses is 1).

[0029] Figure 7 The B4PyMPM-doped UV photoelectric synaptic device prepared in Example 1 of the present invention was subjected to UV irradiation with pulse durations of 0.5s, 1s, 2s, and 3s (all with a wavelength of 265nm and an intensity of 0.356mW / cm 2 , the number of pulses is 1).

[0030] Figure 8 The B4PyMPM-doped UV photoelectric synaptic device prepared in Example 1 of the present invention was subjected to UV irradiation with a bias voltage of 0.005 V and a pulse number N of 10, 20, 30, 40, and 50 (all with a wavelength of 265 nm and an intensity of 0.356 mW / cm 2 , pulse time is 0.5s).

[0031] Figure 9 The near-infrared photodetector device prepared in Example 1 of the present invention is in the dark state and at an intensity of 1.336 mW / cm 2 The current-voltage characteristic curves under 1550 nm near-infrared light irradiation are shown, and the performance under light irradiation is compared with the device without the introduction of the Cs3Cu2I5-B4PyMPM anti-reflection layer.

[0032] Figure 10 The near-infrared photodetector device with the Cs3Cu2I5-B4PyMPM anti-reflection layer prepared in Example 1 of the present invention was tested at an intensity of 1.336 mW / cm 2 Time response curve under 1550 nm near-infrared light irradiation. The figure uses the device without the introduction of the Cs3Cu2I5-B4PyMPM anti-reflection layer as a comparison. DETAILED DESCRIPTION

[0033] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the following embodiments. The following is merely an example and illustration of the concept of the present invention. Any modification, supplement, or substitution of the described specific embodiments by a person skilled in the art, as long as it does not deviate from the concept of the invention or exceed the scope defined by the claims, shall fall within the scope of protection of the present invention.

[0034] Example 1

[0035] like Figure 1As shown, the structure of the ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device based on the Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction in this embodiment is as follows: an n-type Ge substrate 2 is used as the base region of the dual-mode photoelectric device, and an n-type Ge substrate electrode 1 is provided on the lower surface of the n-type Ge substrate 2; a single-layer graphene film 3 is laid on the upper surface of the n-type Ge substrate 2, and the boundary of the single-layer graphene film 3 does not exceed the boundary of the n-type Ge substrate, and the single-layer graphene film 3 forms a heterojunction with the n-type Ge substrate 2; a Cs3Cu2I5-B4PyMPM film 4 is laid on the upper surface of the single-layer graphene film 3, and the Cs3Cu2I5-B4PyMPM film 4 forms a heterojunction with the single-layer graphene 3; and a pair of metal electrodes 5 (Ni electrodes) are provided on a portion of the upper surface of the Cs3Cu2I5-B4PyMPM film 4.

[0036] Specifically, the n-type Ge substrate 2 is a 400 μm thick n-type doped Ge sheet with a resistivity of 0.5-30 Ω / cm. The single-layer graphene film 3 is 0.3 nm thick. The Cs3Cu2I5-B4PyMPM film 4 is 270 nm thick. The metal electrode 5 is 80 nm thick.

[0037] The method for preparing the ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device in this embodiment is carried out according to the following steps:

[0038] (1) An n-type doped Ge wafer with an area of ​​1 cm × 1 cm was used as a substrate and ultrasonically cleaned with deionized water, acetone, and alcohol for 10 minutes each, and then dried with nitrogen.

[0039] (2) Using a graphene wet transfer method, a single-layer graphene film is transferred to the upper surface of an n-type Ge substrate, and the boundary of the single-layer graphene does not exceed the boundary of the above-mentioned n-type Ge substrate.

[0040] (3) 0.54558 g CsI, 0.26663 g CuI, and 0.001 g B4PyMPM (the doping concentration is the ratio of the mass of B4PyMPM to the total mass of CsI and CuI) were added to 1 mL of a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of 4:1. The mixture was kept under magnetic stirring at 25°C for 1 h to complete the reaction and obtain a doped Cs3Cu2I5-B4PyMPM mixed solution. The obtained mixed solution was filtered with a filter and spin-coated on a monolayer graphene at 3000 rpm for 30 s. After the spin-coating lasted for 20 s, the anti-solvent ethyl acetate was added dropwise. The film was then annealed on a hot plate at 80°C for 5 min and then on a hot plate at 100°C for 20 min to obtain a Cs3Cu2I5-B4PyMPM film.

[0041] (4) A pair of Ni electrodes were set on the Cs3Cu2I5-B4PyMPM film by thermal evaporation; an In-Ga alloy electrode was set on the lower surface of the n-type Ge substrate by smearing, thus obtaining a dual-mode optoelectronic device based on the Cs3Cu2I5-B4PyMPM film / graphene / Ge heterojunction.

[0042] The energy band diagram of B4PyMPM, Cs3Cu2I5, graphene and n-type Ge in the dual-mode optoelectronic device prepared in this example is shown in FIG. Figure 2 As shown in the figure hv Represents illumination. It can be seen from the figure that this heterostructure has reasonable band matching.

[0043] In order to study the ultraviolet photoelectric synaptic performance and near-infrared photoelectric detection performance of the dual-mode optoelectronic device prepared in this embodiment, the following tests were performed. At the same time, for better distinction, when studying the ultraviolet photoelectric synaptic performance of the device, the device is referred to as an ultraviolet photoelectric synaptic device, and when studying the near-infrared photoelectric detection performance of the device, the device is referred to as a near-infrared photoelectric detection device.

[0044] 1. Ultraviolet photosynaptic performance

[0045] For comparison, this embodiment also prepared a Cs3Cu2I5 film / graphene / Ge heterojunction-based optoelectronic device with a B4PyMPM doping concentration of 0. The preparation method is the same as the preparation method of the above-mentioned dual-mode optoelectronic device, with the only difference being that the amount of B4PyMPM added in step (3) is 0.

[0046] In the following test of the ultraviolet photosynapse performance, two Ni electrodes were connected to the positive and negative poles of the power supply respectively.

[0047] The time response curves of the UV photoelectric synaptic devices doped with B4PyMPM and undoped with B4PyMPM prepared in this example at a bias voltage of 0.005 V are shown in Figure 2. Figure 3 As shown in the figure, the photoelectric response performance of the UV photoelectric synaptic device doped with B4PyMPM is significantly improved, with the postsynaptic current increasing from 0.25 μA to 1.4 μA. In addition, the UV photoelectric synaptic device prepared in this example can operate normally at low bias voltage, effectively reducing device power consumption.

[0048] The STP response curves of the UV photoelectric synaptic devices doped with B4PyMPM and undoped with B4PyMPM prepared in this example are shown in Figure 2. Figure 4As shown in the figure, it can be seen that the photoelectric response performance of the UV photosynaptic device doped with B4PyMPM is significantly improved. In addition, compared with the device without B4PyMPM, the paired pulse facilitation (PPF) index of the UV photosynaptic device doped with B4PyMPM is increased from 135% to 145%.

[0049] The time response curves of the B4PyMPM-doped UV photoelectric synaptic device prepared in this example to UV light of different wavelengths are shown in FIG. Figure 5 As shown in the figure, it can be seen that the device has good photoelectric response performance to ultraviolet light.

[0050] See also Figure 6 、 Figure 7 、 Figure 8 The LTP response curve of the B4PyMPM-doped ultraviolet photoelectric synaptic device prepared in this embodiment to different light intensities, light pulse durations and light pulse numbers shows that the device exhibits good LTP response with the increase of light intensity, light pulse duration and light pulse number.

[0051] 2. Near-infrared photoelectric detection performance

[0052] For comparison, this embodiment also prepared a graphene / Ge heterojunction optoelectronic device without a Cs3Cu2I5-B4PyMPM film. The preparation method is the same as the preparation method of the above-mentioned dual-mode optoelectronic device, except that step (3) is not performed, and a pair of metal electrodes (Ni electrodes) are directly set on the graphene film.

[0053] In the following test of near-infrared photodetection performance, any one of the Ni electrode and the In-Ga alloy electrode is connected to the positive and negative poles of the power supply, respectively.

[0054] The near-infrared photodetector prepared in this example has a dark state and an intensity of 1.336 mW / cm 2 The current-voltage characteristic curve under 1550nm near-infrared light irradiation is as follows Figure 9 The performance under illumination is shown in Figure 1, and the performance is compared with that of a device without the Cs3Cu2I5-B4PyMPM anti-reflection layer. The figure shows that the short-circuit current increases from 6.01 μA to 8.69 μA after the 270 nm Cs3Cu2I5-B4PyMPM anti-reflection layer is introduced.

[0055] In this embodiment, the near-infrared photodetector before and after the introduction of the 270 nm Cs3Cu2I5-B4PyMPM anti-reflection layer has an intensity of 1.336 mW / cm 2 The time response curve under 1550 nm near-infrared light irradiation is as follows Figure 10As shown in the figure, it can be seen that after the introduction of the 270 nm Cs3Cu2I5-B4PyMPM anti-reflection layer, the photocurrent increased from 6.01 μA to 8.69 μA, which is significantly higher than that of the device before the introduction of the anti-reflection layer. Compared with the near-infrared photoelectric device without the introduction of the anti-reflection layer, the responsivity of the near-infrared photoelectric device with the introduction of the anti-reflection layer increased from 449.8 mA / W to 650.5 mA / W, which is significantly higher than the detection rate D * From 5.15×10 9 Jones increased to 1.43×10 10 Jones, the device has good near-infrared photodetection performance.

[0056] As can be seen from the above, by doping wide-bandgap perovskite films with B4PyMPM as electron-trapping sites, the present invention enhances electron-trapping capabilities, effectively separates photogenerated electrons and holes in physical space, and reduces carrier recombination, thereby increasing the photocurrent amplitude and duration, and improving the performance of ultraviolet photoelectric synaptic devices. By optimizing the thickness of the doped wide-bandgap perovskite film, it serves as an antireflection layer in the 1550 nm near-infrared band, enhancing the performance of near-infrared photodetectors. Based on this, the present invention achieves the dual functions of ultraviolet photosynaptic and near-infrared photodetection in a single device.

[0057] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual-mode photoelectric device with ultraviolet photoelectric synapse and near-infrared photoelectric detection, characterized by: The dual-mode optoelectronic device is provided with a single-layer graphene film on the upper surface of an n-type Ge substrate, and a Cs3Cu2I5-B4PyMPM film is laid on the single-layer graphene film; the n-type Ge substrate and the single-layer graphene film form a heterojunction, and the single-layer graphene film and the Cs3Cu2I5-B4PyMPM film form a heterojunction; The Cs3Cu2I5-B4PyMPM film is obtained by doping a Cs3Cu2I5 film with B4PyMPM.

2. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 1, characterized in that: The dual-mode optoelectronic device realizes the ultraviolet photoelectric synaptic function through the heterojunction composed of the Cs3Cu2I5-B4PyMPM film and the single-layer graphene film, thereby forming an ultraviolet photoelectric synaptic device; The dual-mode optoelectronic device realizes near-infrared photoelectric detection function through a heterojunction composed of an n-type Ge substrate and a single-layer graphene film, forming a near-infrared photoelectric detection device, and the Cs3Cu2I5-B4PyMPM film serves as an anti-reflection layer to improve the performance of the near-infrared photoelectric detection device.

3. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 1 or 2, characterized in that: The preparation method of the Cs3Cu2I5-B4PyMPM film is as follows: B4PyMPM is added to a Cs3Cu2I5 perovskite precursor solution containing CsI and CuI and mixed evenly to obtain a doping solution, and the doping solution is formed into a thin film on a target substrate by spin coating, thereby obtaining a Cs3Cu2I5-B4PyMPM film.

4. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 3, characterized in that: In the doping solution, the mass of B4PyMPM accounts for 0.05-0.15 wt % of the total mass of CsI and CuI.

5. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 1 or 2, characterized in that: When the dual-mode optoelectronic device is used as a near-infrared photodetector, the anti-reflection wavelength when it is used as an anti-reflection layer in the near-infrared light band is regulated by adjusting the thickness of the Cs3Cu2I5-B4PyMPM film.

6. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 5, characterized in that: A Cs3Cu2I5-B4PyMPM film with a thickness of 260-280 nm is used as the anti-reflection layer in the 1550 nm band.

7. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 1 or 2, characterized in that: An n-type Ge substrate electrode is arranged on the lower surface of the n-type Ge substrate; and a metal electrode is arranged on the Cs3Cu2I5-B4PyMPM film.

8. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 1 or 2, characterized in that: The n-type Ge substrate is an n-type doped Ge sheet with a resistivity of 0.5-30 Ω / cm.

9. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 7, characterized in that: The n-type Ge substrate electrode is an In-Ga alloy electrode; the metal electrode is a Ni electrode with a thickness of 60-100 nm.

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