Ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device

Abstract

The invention relates to a photoelectric device for generating electric energy through conversion of ultraviolet light and near-infrared light, and discloses an ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device. The dual-mode photoelectric device integrates dual functions of ultraviolet photoelectric synapse and near-infrared photoelectric detection: the ultraviolet photoelectric synapse function is realized based on a heterojunction formed by a single-layer graphene film and a wide bandgap perovskite Cs3Cu2I5 film, and B4PyMPM is doped in the Cs3Cu2I5 film to serve as an electron capture site, so that the electron capture capability is enhanced, and the photoelectric detection efficiency is improved. The performance of the ultraviolet photoelectric synapse device can be improved; a near-infrared photoelectric detection function is realized based on a heterojunction formed by a single-layer graphene thin film and n-type Ge, and the thickness of the Cs3Cu2I5 thin film is optimized, so that the Cs3Cu2I5 thin film becomes an antireflection layer of a 1550 nm near-infrared band, and the responsivity, the specific detection rate and other properties of a near-infrared photoelectric detection device are improved. The device disclosed by the invention is simple in structure and process, expensive instruments and equipment are avoided, and the preparation cost of the device is reduced.

Description

Technical Field

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

[0002] A photodetector is an optoelectronic conversion device that can quickly convert optical signals into electrical signals. It has high responsivity and sensitivity and is widely used in many scientific research and industrial technology fields such as image sensing, fiber optic communication, photoelectric detection, fire monitoring, biomedical imaging, environmental monitoring, space exploration, and security detection. However, photodetectors cannot permanently store images or process complex time-series data, which limits their application in certain scenarios. Photoelectric synapse devices are another important type of optoelectronic conversion device. Inspired by biological neural synapses, these devices can realize efficient brain-like information processing and storage by simulating the plasticity function of biological synapses, and thus can realize the perception, storage, and processing of optical signals.

[0003] The rapid development of emerging artificial intelligence technologies such as robots and autonomous driving has put forward higher requirements for the multifunctionality of optoelectronic devices. People hope to integrate multiple functions such as photoelectric detection, information processing, sensing, storage, and even logical operations in a single device or a compact system, thereby reducing the device volume, reducing the device power consumption, improving the device efficiency, and enhancing the intelligence level. Currently, multi-mode optoelectronic devices usually integrate many single-function devices into a system, which inevitably increases the complexity, volume, and power consumption of the system, and also brings many inconveniences in use. Integrating photoelectric detection and neural synapse functions in a single device to construct a dual-mode optoelectronic device will help improve the integration degree of optoelectronic devices and expand their application fields. However, due to the different working mechanisms of the two devices and the huge difference in the optical response speed, it is very difficult to simultaneously realize photoelectric detection and neural synapse functions in a single device. In addition, due to the limited response wavelength range of the photosensitive materials in optoelectronic devices, it is more challenging to integrate photoelectric detection and neural synapse functions with different response wavelength ranges in the same optoelectronic device.

[0004] Currently, the main approach to developing high-performance ultraviolet optoelectronic synaptic devices is to use wide-bandgap semiconductor oxides as the photosensitive layer, and to simulate the functions of neural synapses by utilizing the persistent photoconductivity phenomenon induced by the ionization and dissociation of oxygen vacancies in the oxide semiconductor. However, it is difficult to regulate the ionization and dissociation processes of oxygen vacancies, making it very difficult to optimize the device performance. Wide-bandgap perovskites have excellent properties such as high ultraviolet light absorption coefficient, tunable optical bandgap, and low defect density. Constructing a heterojunction based on wide-bandgap perovskites and using their matched energy levels to achieve selective conduction of photo-generated carriers is one of the effective strategies for fabricating high-performance ultraviolet optoelectronic synaptic devices. However, there is relatively serious recombination of photo-generated carriers inside the wide-bandgap perovskites. Photo-generated electrons and holes may be simultaneously injected into the conduction layer, resulting in more serious carrier recombination, thus leading to poor device performance and hindering practical applications. In addition, using two-dimensional material / narrow-bandgap semiconductor heterostructures is expected to achieve low-cost and high-performance near-infrared light detection. However, due to the relatively 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 a high reflectivity to near-infrared light, making it difficult to further improve the device performance. Summary of the Invention

[0005] The present invention is to avoid the deficiencies of the above-mentioned prior art, and provides an ultraviolet optoelectronic synaptic / near-infrared photodetection dual-mode optoelectronic device, aiming to construct a Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction. By doping with B4PyMPM to enhance the electron capture ability, the performance of ultraviolet optoelectronic synapses can be effectively improved. At the same time, by optimizing the thickness of the wide-bandgap perovskite thin film, the wide-bandgap perovskite thin film becomes an antireflection layer in a specific band, effectively improving the responsivity, specific detectivity and other near-infrared photodetection performances, so as to obtain an optoelectronic device integrating the dual functions of ultraviolet optoelectronic synapses and near-infrared photodetection.

[0006] The present invention adopts the following technical solutions to solve the technical problems: The present invention first provides an ultraviolet optoelectronic synaptic / near-infrared photodetection dual-mode optoelectronic device, which is characterized in that: a single-layer graphene thin film is provided on the upper surface of an n-type Ge substrate, and a Cs3Cu2I5-B4PyMPM thin film is laid on the single-layer graphene thin film; the n-type Ge substrate and the single-layer graphene thin film form a heterojunction, and the single-layer graphene thin film and the Cs3Cu2I5-B4PyMPM thin film form a heterojunction; the Cs3Cu2I5-B4PyMPM thin film is obtained by doping a Cs3Cu2I5 thin film with B4PyMPM (4,6-bis(3,5-di(4-pyridyl)phenyl)-2-methylpyrimidine).

[0007] The dual-mode optoelectronic device can achieve the dual functions of ultraviolet photoelectric synapse and near-infrared photoelectric detection, and the implementation method is as follows: The ultraviolet photoelectric synapse function is realized through the heterojunction formed by the Cs3Cu2I5-B4PyMPM thin film and the single-layer graphene thin film, and the ultraviolet photoelectric synapse device is formed. Among them, by doping the Cs3Cu2I5 thin film with B4PyMPM, the electron capture ability is enhanced, the carrier recombination is reduced, the efficient separation and transmission of photo-generated carriers are realized, the decline amplitude of the photocurrent is reduced, and the duration of the photocurrent is increased, thereby improving the performance of the ultraviolet photoelectric synapse device.

[0008] The near-infrared photoelectric detection function is realized through the heterojunction formed by the n-type Ge substrate and the single-layer graphene thin film, and the near-infrared photoelectric detection device is formed. Moreover, the Cs3Cu2I5-B4PyMPM thin film is used as an antireflection layer to improve the performance such as the responsivity and specific detectivity of the near-infrared photoelectric detection device. Among them: by adjusting the thickness of the Cs3Cu2I5-B4PyMPM thin film, the antireflection wavelength when it is used as an antireflection layer in the near-infrared light band can be adjusted. For example, a Cs3Cu2I5-B4PyMPM thin film with a thickness of 260-280 nm is used as the antireflection layer for the 1550 nm band.

[0009] Furthermore, the preparation method of the Cs3Cu2I5-B4PyMPM thin film is as follows: B4PyMPM is added to the Cs3Cu2I5 perovskite precursor solution containing CsI and CuI and mixed evenly to obtain a doped solution, and the doped solution is spin-coated on the target substrate to form a thin film, that is, the Cs3Cu2I5-B4PyMPM thin film is obtained. In the doped solution, the mass of B4PyMPM accounts for 0.05-0.15 wt% of the total mass of CsI and CuI.

[0010] Furthermore, 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 thin film.

[0011] To further optimize the performance of the dual-mode optoelectronic device, the following parameters are set: the n-type Ge substrate uses an n-type doped Ge wafer with a resistivity of 0.5-30 Ω / cm. The thickness of the Cs3Cu2I5-B4PyMPM thin film is 260-280 nm. 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.

[0012] The preparation method of the ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device of the present invention can be carried out according to the following steps: (1) The n-type Ge substrate was ultrasonically cleaned successively with deionized water, acetone, and alcohol, and dried with nitrogen. (2) Using the graphene wet transfer method, a single-layer graphene film was transferred to the upper surface of the above-mentioned n-type Ge substrate, and the boundary of the single-layer graphene film did not exceed the boundary of the above-mentioned n-type Ge substrate. (3) A perovskite precursor solution containing B4PyMPM was prepared and then spin-coated on the upper surface of the single-layer graphene film to form a Cs3Cu2I5-B4PyMPM film. (4) A metal electrode was set on the Cs3Cu2I5-B4PyMPM film by methods such as thermal evaporation; an n-type Ge substrate electrode was set on the lower surface of the n-type Ge substrate by methods such as coating or thermal evaporation coating, and thus a dual-mode optoelectronic device based on the Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction for ultraviolet photoelectric synapse / near-infrared photoelectric detection was obtained.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By constructing a Cs3Cu2I5-B4PyMPM / graphene / Ge heterostructure, the present invention simultaneously realizes the functions of ultraviolet photoelectric synapse and near-infrared photoelectric detection in the same device. When used as an ultraviolet photoelectric synapse device, the high absorption rate of ultraviolet light by the wide-bandgap perovskite is utilized, and combined with the advantages of increasing the electron capture ability by B4PyMPM doping, etc., the absorption efficiency of the detected light and the separation and transport efficiency of photogenerated carriers are improved. When used as a near-infrared photoelectric detection device, the wide-bandgap perovskite Cs3Cu2I5 film doped with B4PyMPM is used as an antireflection layer, greatly improving the near-infrared photoelectric detection performance.

[0014] 2. The Cs3Cu2I5-B4PyMPM film in the dual-mode optoelectronic device of the present invention can be prepared by the spin-coating method, with a simple process, avoiding expensive instrument equipment and reducing the device preparation cost.

[0015] 3. The dual-mode optoelectronic device of the present invention can operate at a low bias voltage, consuming only a small amount of external energy, and thus can effectively reduce power consumption. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the dual-mode optoelectronic device based on the Cs3Cu2I5-B4PyMPM / graphene / Ge heterojunction of the present invention. In the figure, the label: 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.

[0017] Figure 2Band diagrams of B4PyMPM, Cs3Cu2I5, graphene, and n-type Ge.

[0018] Figure 3 Time response curves of the doped and undoped B4PyMPM ultraviolet optoelectronic synaptic devices prepared in Example 1 of the present invention under an ultraviolet light illumination with a wavelength of 265 nm, a pulse time of 1 s, and an intensity of 0.356 mW / cm 2 at a bias voltage of 0.005 V.

[0019] Figure 4 Time response curves of the doped and undoped B4PyMPM ultraviolet optoelectronic synaptic devices prepared in Example 1 of the present invention under an ultraviolet light illumination with a wavelength of 265 nm, a pulse time of 1 s, and an intensity of 0.356 mW / cm 2 at a bias voltage of 0.005 V. The STP response curve (STP represents short-term plasticity) is shown in the figure, where A1 is the excitatory postsynaptic current of the first light pulse stimulation and A2 is the excitatory postsynaptic current of the second light pulse stimulation.

[0020] Figure 5 Time response curves of the doped B4PyMPM ultraviolet optoelectronic synaptic device prepared in Example 1 of the present invention under ultraviolet light illuminations with wavelengths of 254 nm, 265 nm, 300 nm, and 365 nm (pulse time is 1 s for all, and intensity is 0.356 mW / cm 2 ) at a bias voltage of 0.005 V.

[0021] Figure 6 LTP response curves (LTP represents long-term plasticity, and STP represents short-term plasticity) of the doped B4PyMPM ultraviolet optoelectronic synaptic device prepared in Example 1 of the present invention under ultraviolet light illuminations with intensities of 0.356 mW / cm 2 , 0.767 mW / cm 2 , 1.170 mW / cm 2 , 1.560 mW / cm 2 , 1.920 mW / cm 2 at a bias voltage of 0.005 V (wavelength is 265 nm for all, pulse time is 1 s for all, and the number of pulses is 1).

[0022] Figure 7 Time response curves of the doped B4PyMPM ultraviolet optoelectronic synaptic device prepared in Example 1 of the present invention under ultraviolet light illuminations with pulse times of 0.5 s, 1 s, 2 s, and 3 s (wavelength is 265 nm for all, and intensity is 0.356 mW / cm 2, LTP response curves under (with the number of pulses all being 1).

[0023] Figure 8 For the ultraviolet photoelectric synaptic device doped with B4PyMPM prepared in Example 1 of the present invention, under a bias voltage of 0.005 V, under ultraviolet light illumination (with the wavelength all being 265 nm and the intensity all being 0.356 mW / cm 2 , and the pulse time all being 0.5 s), the LTP response curves.

[0024] Figure 9 For the near-infrared photodetector prepared in Example 1 of the present invention, the current-voltage characteristic curves in the dark state and under the illumination of 1550 nm near-infrared light with an intensity of 1.336 mW / cm 2 , and the performance under illumination is compared with the device without the Cs3Cu2I5-B4PyMPM antireflection layer.

[0025] Figure 10 For the near-infrared photodetector with the Cs3Cu2I5-B4PyMPM antireflection layer prepared in Example 1 of the present invention, the time response curve under the illumination of 1550 nm near-infrared light with an intensity of 1.336 mW / cm 2 , and in the figure, the device without the Cs3Cu2I5-B4PyMPM antireflection layer is used as a comparison. Detailed implementation manners

[0026] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention is given in conjunction with the embodiments. The following content is only an example and explanation of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements or use similar methods to replace the described specific embodiments, as long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

[0027] Example 1 As Figure 1As shown in the figure, the structure of the ultraviolet photoelectric synaptic / near-infrared photoelectric detection dual-mode optoelectronic 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 optoelectronic 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; A pair of metal electrodes 5 (Ni electrodes) are provided in a partial area on the upper surface of the Cs3Cu2I5-B4PyMPM film 4.

[0028] Specifically: The n-type Ge substrate 2 uses an n-type doped Ge wafer with a thickness of 400 μm and a resistivity of 0.5 - 30 Ω / cm. The thickness of the single-layer graphene film 3 is 0.3 nm. The thickness of the Cs3Cu2I5-B4PyMPM film 4 is 270 nm. The thickness of the metal electrode 5 is 80 nm.

[0029] The preparation method of the ultraviolet photoelectric synaptic / near-infrared photoelectric detection dual-mode optoelectronic device in this embodiment is carried out according to the following steps: (1) Take an n-type doped Ge wafer with an area of 1 cm × 1 cm as the substrate and ultrasonically clean it with deionized water, acetone, and alcohol for 10 minutes each, and dry it with nitrogen.

[0030] (2) Use the graphene wet transfer method to transfer the single-layer graphene film to the upper surface of the 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.

[0031] (3) Add 0.54558 g of CsI, 0.26663 g of CuI, and 0.001 g of B4PyMPM (the doping concentration is the mass ratio of B4PyMPM to the total mass of CsI and CuI) to 1 mL of a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of 4:1, and keep stirring magnetically at 25 °C for 1 h to complete the reaction and obtain a doped Cs3Cu2I5-B4PyMPM mixed solution. After filtering the obtained mixed solution with a filter, spin-coat it on the single-layer graphene for 30 s under the condition of 3000 rpm. Add the antisolvent ethyl acetate when spinning for 20 s, and then anneal it on a hot plate at 80 °C for 5 min first, and then anneal it on a hot plate at 100 °C for 20 min to obtain the Cs3Cu2I5-B4PyMPM film.

[0032] (4) A pair of Ni electrodes were set on the Cs3Cu2I5-B4PyMPM film by thermal evaporation method; an In-Ga alloy electrode was set on the lower surface of the n-type Ge substrate by smearing method, thus obtaining a dual-mode optoelectronic device based on Cs3Cu2I5-B4PyMPM film / graphene / Ge heterojunction.

[0033] The energy band diagrams of B4PyMPM, Cs3Cu2I5, graphene and n-type Ge in the dual-mode optoelectronic device prepared in this embodiment are as Figure 2 shown in the figure, where hv represents light illumination. It can be seen from the figure that this heterostructure has reasonable energy band matching.

[0034] 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 carried out. At the same time, for better distinction, the device was called an ultraviolet photoelectric synaptic device when studying the ultraviolet photoelectric synaptic performance of the device, and the device was called a near-infrared photoelectric detection device when studying the near-infrared photoelectric detection performance of the device.

[0035] 1. Ultraviolet photoelectric synaptic performance For comparison, this embodiment also prepared an optoelectronic device based on Cs3Cu2I5 film / graphene / Ge heterojunction with a B4PyMPM doping concentration of 0. Its preparation method is the same as that of the above dual-mode optoelectronic device, and the only difference is that the addition amount of B4PyMPM in step (3) is 0.

[0036] In the following tests of ultraviolet photoelectric synaptic performance, the two Ni electrodes were respectively connected to the positive and negative poles of the power supply.

[0037] The time response curves of the ultraviolet photoelectric synaptic devices doped with B4PyMPM and undoped with B4PyMPM prepared in this embodiment under a bias voltage of 0.005 V are as Figure 3 shown in the figure. It can be seen from the figure that the photoelectric response performance of the ultraviolet photoelectric synaptic device doped with B4PyMPM has been significantly improved, and the postsynaptic current has increased from 0.25 μA to 1.4 μA. In addition, the ultraviolet photoelectric synaptic device prepared in this embodiment can work normally under low bias voltage, which can effectively reduce the power consumption of the device.

[0038] The STP response curves of the ultraviolet photoelectric synaptic devices doped with B4PyMPM and undoped with B4PyMPM prepared in this embodiment are as Figure 4 shown in the figure. It can be seen from the figure that the photoelectric response performance of the ultraviolet photoelectric synaptic device doped with B4PyMPM has been significantly improved. In addition, compared with the device undoped with B4PyMPM, the paired pulse facilitation (PPF) index of the ultraviolet photoelectric synaptic device doped with B4PyMPM has increased from 135% to 145%.

[0039] The time response curves of the ultraviolet photoelectric synaptic device doped with B4PyMPM prepared in this embodiment for ultraviolet light of different wavelengths are as Figure 5 shown. It can be seen from the figure that the device has good photoelectric response performance to ultraviolet light.

[0040] See Figure 6 、 Figure 7 、 Figure 8 for the LTP response curves of the ultraviolet photoelectric synaptic device doped with B4PyMPM prepared in this embodiment in this example for different light intensities, light pulse durations and light pulse numbers. It can be seen from the figure that as the light intensity increases, the light pulse duration increases, and the light pulse number increases, the device shows good LTP response.

[0041] 2. Near-infrared photodetection performance For comparison, in this embodiment, a graphene / Ge heterojunction optoelectronic device without a Cs3Cu2I5-B4PyMPM thin film was also prepared. Its preparation method is the same as that of the above 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 thin film.

[0042] In the following test of near-infrared photodetection performance, any one Ni electrode and an In-Ga alloy electrode are respectively connected to the positive and negative poles of the power supply.

[0043] The current-voltage characteristic curves of the near-infrared photodetector prepared in this embodiment in the dark state and under the irradiation of 1550 nm near-infrared light with an intensity of 1.336 mW / cm 2 are as Figure 9 shown, and the performance under illumination is compared with the device without the Cs3Cu2I5-B4PyMPM antireflection layer introduced. It can be seen from the figure that after introducing the 270 nm Cs3Cu2I5-B4PyMPM antireflection layer, the short-circuit current increases from 6.01 μA to 8.69 μA.

[0044] The time response curves of the near-infrared photodetector before and after introducing the 270 nm Cs3Cu2I5-B4PyMPM antireflection layer in this embodiment under the irradiation of 1550 nm near-infrared light with an intensity of 1.336 mW / cm 2 are as Figure 10As shown, it can be seen from the figure that after introducing the 270 nm Cs3Cu2I5-B4PyMPM antireflection layer, the photocurrent increases from 6.01 μA to 8.69 μA, which is significantly higher than that of the device before the introduction of the antireflection layer. Compared with the near-infrared optoelectronic device without the antireflection layer, the responsivity of the near-infrared optoelectronic device with the antireflection layer increases from 449.8 mA / W to 650.5 mA / W, and the specific detectivity D * increases from 5.15×10 9 Jones to 1.43×10 10 Jones, indicating that this device has good performance in near-infrared photoelectric detection.

[0045] As described above, in the present invention, by doping B4PyMPM as an electron trapping site in the wide-bandgap perovskite thin film, the electron trapping ability is enhanced, the effective separation of photogenerated electrons and holes in physical space is achieved, and the carrier recombination is reduced, thereby increasing the photocurrent amplitude and prolonging the photocurrent duration, and improving the performance of the ultraviolet photoelectric synaptic device. By optimizing the thickness of the doped wide-bandgap perovskite thin film to make it an antireflection layer in the 1550 nm near-infrared band, the performance of the near-infrared photodetector is improved. Based on this, the present invention realizes the dual functions of ultraviolet photoelectric synapse and near-infrared photoelectric detection with a single device.

[0046] The above are only exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device, characterized in that: The dual-mode optoelectronic device has a single-layer graphene film disposed 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.

2. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 1, wherein: The dual-mode optoelectronic device realizes the ultraviolet photoelectric synapse function through the heterojunction formed by the Cs3Cu2I5-B4PyMPM film and the single-layer graphene film, and forms an ultraviolet photoelectric synapse device; The dual-mode optoelectronic device realizes the near-infrared photoelectric detection function through the heterojunction formed by the n-type Ge substrate and the single-layer graphene film, and forms a near-infrared photoelectric detection device, and the Cs3Cu2I5-B4PyMPM film is used as an antireflection 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 spin-coated on a target substrate to form a film, that is, the Cs3Cu2I5-B4PyMPM film is obtained.

4. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 3, wherein: 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 photoelectric detection device, the antireflection wavelength of the Cs3Cu2I5-B4PyMPM film as an antireflection layer in the near-infrared light band is adjusted by controlling the thickness of the Cs3Cu2I5-B4PyMPM film.

6. The ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode optoelectronic device according to claim 5, wherein, A Cs3Cu2I5-B4PyMPM film with a thickness of 260-280 nm is used as an antireflection 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 disposed on the lower surface of the n-type Ge substrate; a metal electrode is disposed 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 uses an n-type doped Ge wafer 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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