Bifunctional bidirectional wide-spectrum photoelectric response device

Abstract

The invention discloses a bifunctional bidirectional wide-spectrum photoelectric response device, which structurally comprises two layers of photoactive materials, namely a lead-free perovskite layer and a donor-acceptor copolymer semiconductor layer, the photoanode and the photocathode are respectively a transparent conductive electrode layer and a metal electrode layer; the solar cell further comprises a hole-transport material layer. The device can realize the functions of negative light detection and positive light synapse. The modulation method comprises the steps that visible light is applied, the device achieves negative light detection, and the light response amplitude is gradually increased along with increase of light intensity; the short-wave infrared light is applied, the device realizes a forward photosynaptic function, and the device gradually realizes the conversion from short-term memory to long-term memory along with the enhancement of photostimulation. The method can be applied to the fields of decoding of multispectral optical signals, multispectral imaging and optical communication.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic semiconductors, and particularly relates to a dual-functional bidirectional wide-spectrum optoelectronic response device. Background Art

[0002] In the prior art, multifunctional optoelectronic devices with negative photoresponse are relatively rare. Based on the characteristic that defects are inevitably introduced during the crystallization process of perovskite materials, these defects can serve as carrier recombination centers. By utilizing the trapping effect of defect states on carriers, the effective contribution of photo-generated carriers can be suppressed, thereby achieving negative photoelectric response. In addition, most of the current dual-functional optoelectronic response devices only support single-direction response, while optoelectronic detectors and optoelectronic synapses with bidirectional response are relatively rare. Integrating light detection and light synaptic functions on a single device and dynamically switching the response mode according to the application scenario can significantly improve the multifunctionality of the device and meet the multifunctional requirements of complex systems. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a dual-functional bidirectional wide-spectrum optoelectronic response device. Through wavelength regulation, this device exhibits dual-functional bidirectional characteristics of negative light detection and positive light synaptic simulation on the same device, solving the problems of single functionality, fixed response direction, limited spectral range, complex timing control, and material and structure limitations in the prior art, and providing a new solution for the development of multifunctional, wide-spectrum, and high-integration optoelectronic response devices.

[0004] The present invention adopts the following technical solutions to solve the above technical problems:

[0005] A dual-functional bidirectional wide-spectrum optoelectronic response device includes two layers of photoactive materials, a photoanode, a photocathode, and a hole transport material layer. Among them, the two layers of photoactive materials are a lead-free perovskite layer and a donor-acceptor copolymer semiconductor layer respectively; the photoanode is a transparent conductive electrode layer, and the photocathode is a metal electrode layer; the hole transport material layer is used to transport holes, block electrons, and modify the transparent conductive electrode layer; under different illumination conditions, the carrier transport and storage characteristics change, so that the device exhibits dual-functional bidirectional characteristics of negative light detection and positive light synaptic simulation on the same device.

[0006] The structure of the optoelectronic response device is arranged in sequence as a transparent conductive electrode layer, a hole transport material layer, a lead-free perovskite layer, a donor-acceptor copolymer semiconductor layer, and a metal electrode layer.

[0007] The material of the transparent conductive electrode layer is selected from one of ITO or FTO, and is prepared by magnetron sputtering method, with a thickness of 130 nm to 150 nm.

[0008] The hole transport material layer is a p-type semiconductor, which is used to transport holes, block electrons, and modify the transparent conductive electrode layer. It is prepared from an aqueous solution of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, and has a thickness of 30 nm to 40 nm.

[0009] The lead-free perovskite layer is CsBi 3 I 10 , CsAgBiBr 6 or CsBi 3 Br 10 and has a thickness of 300 nm to 350 nm.

[0010] The donor-acceptor copolymer semiconductor layer is one of polybenzobisthiadiazole-dithiophene cyclopentane, polybenzobisthiadiazole-dithienopyrrole, or alkoxybenzene-substituted thiadiazoloquinoline-thiophene, and has a thickness of 150 nm to 200 nm.

[0011] The metal electrode layer is one of gold or silver, and is prepared by vacuum evaporation, with a thickness of 30 nm to 50 nm.

[0012] The functions of negative photodetection and positive optical synapse are realized. The specific modulation method is as follows: Visible light is applied to the device to realize the negative photodetection function, and as the light intensity increases, the photoresponse amplitude gradually increases; Short-wave infrared light is applied to the device to realize the positive optical synapse function, and as the light stimulus increases, the device gradually realizes the transition from short-term memory to long-term memory.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The lead-free perovskite material used in the present invention is non-toxic and environmentally friendly, and is friendly to the environment; The donor-acceptor copolymer semiconductor material used in the present invention is easy to process and its structure can be adjusted. The optical bandgap can be reduced by adjusting the strength and arrangement of the electron-withdrawing group and the electron-donating group in its structure, so as to realize the response to short-wave infrared light. Short-wave infrared light has low light scattering and strong penetration, which is of great significance in depth imaging and environmental detection.

[0015] 2. The dual-functional bidirectional broadband photoelectric response device prepared by the present invention realizes the integration of negative photodetection and positive optical synapse on a single device. Negative-response photodetectors are relatively rare. Due to various defects that will inevitably appear during the crystallization process of perovskite materials, these defects will become sites for some carrier recombination. By utilizing this feature, the carriers excited by photons are captured in these defects to inhibit the contribution of carriers, thereby generating a negative photoelectric response. The device has a selective response to light of different wavelengths, and different light mode responses can be achieved by controlling the wavelength. This characteristic is applied to the fields of multi-spectral optical signal decoding, multi-spectral imaging, and optical communication. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the dual-functional bidirectional wide-spectrum optoelectronic response device of the present invention.

[0017] Figure 2a It is the current-voltage (I-V) characteristic curves of the dual-functional bidirectional wide-spectrum optoelectronic response device in Example 1 of the present invention under darkness, visible light (532 nm, 6.5 mW cm -2 ) and short-wave infrared light (1550 nm, 87 mW cm -2 ).

[0018] Figure 2b It is Figure 2a The partial enlarged view between -0.035V and 0.02 V.

[0019] Figure 3 It is the optical switching performance of the dual-functional bidirectional wide-spectrum optoelectronic response device in Example 2 of the present invention under visible light of 532 nm at different light intensities from 3.8 mW cm -2 to 6.5 mW cm -2 .

[0020] Figure 4a It is the photocurrent of the dual-functional bidirectional wide-spectrum optoelectronic response device in Example 2 of the present invention under continuous visible light (532 nm, 6.5 mW cm -2 ) irradiation for 1000 s.

[0021] Figure 4b It is the photocurrent and dark current of the dual-functional bidirectional wide-spectrum optoelectronic response device in Example 2 of the present invention under continuous operation for 148 on / off cycles.

[0022] Figure 4c And Figure 4d It is Figure 4b The partial enlarged view of.

[0023] Figure 5a It is the double-pulse facilitation behavior induced by two consecutive light pulses (light pulse parameters: 1550 nm, 87 mW cm -2 , light pulse time 2 s, interval time 2 s) of the dual-functional bidirectional wide-spectrum optoelectronic response device in Example 3 of the present invention.

[0024] Figure 5b It is the trend of the double-pulse facilitation index of the dual-functional bidirectional wide-spectrum optoelectronic response device in Example 3 of the present invention changing with the interval time under a fixed light intensity (87 mW cm -2 ) and a fixed light pulse time (2 s), where the solid line is obtained by fitting with an exponential function.

[0025] Figure 5c This is the synaptic plasticity change of the dual-functional bidirectional broadband photoelectric response device in Example 3 of the present invention under short-wave infrared light (1550 nm, 87 mW cm -2 ) as the optical pulse time gradually increases.

[0026] Figure 5d This is the synaptic plasticity change of the dual-functional bidirectional broadband photoelectric response device in Example 3 of the present invention under short-wave infrared light (1550 nm, 87 mW cm -2 ) as the number of optical pulses gradually increases.

[0027] Figure 6a This is the optical switching performance of the dual-functional bidirectional broadband photoelectric response device in Example 4 of the present invention under visible light at 532 nm, 6.5 mW cm -2 .

[0028] Figure 6b This is the paired-pulse facilitation behavior induced by two consecutive optical pulses (optical pulse parameters: 1550 nm, 87 mW cm -2 , optical pulse time 2 s, interval time 2 s) of the dual-functional bidirectional broadband photoelectric response device in Example 4 of the present invention. Detailed implementation manners

[0029] The structure and working process of the present invention will be further described below with reference to the accompanying drawings.

[0030] A dual-functional bidirectional broadband photoelectric response device includes two layers of photoactive materials, a photoanode, a photocathode, and a hole transport material layer. Among them, the two layers of photoactive materials are a lead-free perovskite layer and a donor-acceptor copolymer semiconductor layer respectively; the photoanode is a transparent conductive electrode layer, and the photocathode is a metal electrode layer; the hole transport material layer is used to transport holes, block electrons, and modify the transparent conductive electrode layer; under different light illumination conditions, the carrier transport and storage characteristics change, so that on the same device, dual-functional bidirectional characteristics of negative photodetection and positive photo-synaptic simulation are exhibited.

[0031] The preparation method of the dual-functional bidirectional broadband photoelectric response device includes the following steps:

[0032] Step S1, preparing the transparent conductive electrode layer of the dual-functional bidirectional broadband photoelectric response device;

[0033] Step S2, sequentially preparing a hole transport material layer, a lead-free perovskite layer, and a donor-acceptor copolymer semiconductor layer on the transparent conductive electrode prepared in Step S1 by spin coating;

[0034] Step S3. Vacuum deposit a metal electrode on the donor-acceptor copolymer semiconductor layer prepared in Step S2.

[0035] Example 1

[0036] Figure 1 is a schematic diagram of the structure of the bifunctional bidirectional broadband photoelectric response device of the present invention. Along the direction of light incidence, there are, in sequence, a transparent conductive electrode layer, a hole transport layer, a lead-free perovskite layer, a donor-acceptor copolymer semiconductor layer, and a metal electrode layer. In this Example 1, the transparent conductive electrode layer is made of ITO, the hole transport layer material is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), and the lead-free perovskite layer is made of CsBi 3 I 10 , the donor-acceptor copolymer semiconductor layer is made of polybenzobisthiadiazole-dithienocyclopentane, and the metal electrode layer is made of gold.

[0037] The preparation method of the bifunctional bidirectional broadband photoelectric response device provided in this example includes the following steps in sequence:

[0038] Step S1. Ultrasonically clean the transparent conductive electrode successively with acetone, ultrapure water, and isopropyl alcohol, dry the surface with a nitrogen gun, and place the transparent conductive electrode in a plasma cleaner for treatment and standby;

[0039] Step S2.1. Mix poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and pure water evenly at a volume ratio of 1:1, and then spin-coat it on the transparent conductive electrode at 4000 rpm for 25 s, and anneal it at 150 °C for 30 min to obtain the hole transport layer.

[0040] Step S2.2. Dissolve bismuth iodide and cesium iodide in a solution of DMF and DMSO with a concentration of 0.75 mol L -1 ~1.34mol L -1 , and spin-coat it on the hole transport material layer at 500 rpm for 10 s and 3500 rpm for 40 s, and anneal it at 125 °C for 30 min to obtain the lead-free perovskite layer.

[0041] Step S2.3. Dissolve polybenzobisthiadiazole-dithienocyclopentane in a chlorobenzene solution with a concentration of 10mg mL -1 ~ 15 mg mL -1 , and then spin-coat it on the lead-free perovskite layer at 2000 rpm for 60 s, and anneal it at 90 °C for 30 min to obtain the donor-acceptor copolymer semiconductor layer.

[0042] The structural formula of polybenzobisthiadiazole-dithienocyclopentane is as follows

[0043]

[0044] Step S3, by means of a mask, deposit a 30-nm-thick gold electrode onto the donor-acceptor copolymer semiconductor under a high vacuum of 1×10 -3 Pa to obtain a bifunctional bidirectional broadband optoelectronic response device.

[0045] For the bifunctional bidirectional broadband optoelectronic response device provided in Example 1, under room-temperature atmospheric conditions, the current-voltage (I-V) characteristic curves of the device were measured using an FS-Pro semiconductor parameter analyzer combined with a probe station under dark conditions, 532-nm and 1550-nm laser irradiations, respectively.

[0046] As Figure 2a 、 Figure 2b shown, in the voltage range of -0.035V to -0.021V, the current under 532-nm laser irradiation is less than the dark current, while the current under 1550-nm laser irradiation is higher than the dark current.

[0047] Example 2

[0048] Adjust the voltage of the bifunctional bidirectional broadband optoelectronic response device prepared in Example 1 to -0.03V, and it can be used as a photodetector with a negative response under 532-nm laser irradiation.

[0049] Adjust the light intensity of the 532-nm laser from 3.8 mW cm -2 ~ 6.5 mW cm -2 to obtain the optical switching performance of the device at different light intensities. It can be seen that as the light intensity increases, the photocurrent of the device gradually decreases and the response amplitude gradually increases, as Figure 3 shown.

[0050] Test the continuous light irradiation stability of the device. It can be seen that the photocurrent does not change significantly after 1000 s of 532-nm laser irradiation; test the cycling stability of the device. It can be seen that there is no significant change after 148 light irradiation switching cycles; the device exhibits good continuous light irradiation stability and cycling stability, as Figure 4a 、 Figure 4b 、 Figure 4c and Figure 4d shown.

[0051] Example 3

[0052] Adjust the voltage of the bifunctional bidirectional broadband optoelectronic response device prepared in Example 1 to -0.03V, and it can be used as a photonic synapse with a positive response under 1550-nm laser irradiation.

[0053] Double-pulse facilitation is a typical short-term synaptic plasticity behavior and is of great significance in the recognition and decoding of temporary information in biological systems. By testing the photocurrent of the postsynaptic current induced by two consecutive identical light pulses with an interval of 2 s, it can be seen that the photocurrent induced by the second light pulse of the device is significantly higher than that of the first light pulse. Moreover, with the increase of the interval time, the double-pulse facilitation index decays exponentially, as Figure 5a and Figure 5b shown.

[0054] Short-term memory and long-term memory are two types of synaptic memory in the biological nervous system and are manifestations of synaptic plasticity. By applying a continuous external stimulus signal during the memory process, the memory level is consolidated, enabling the transformation of short-term memory in the cerebral cortex into long-term memory. By increasing the duration of light irradiation and the number of light pulses, it can be seen that the decay of the photocurrent of the postsynaptic current slows down, as Figure 5c and Figure 5d shown.

[0055] Example 4

[0056] In this example, the transparent conductive electrode layer is made of ITO, the hole transport layer material is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), the lead-free perovskite layer is CsBi 3 I 10 , and the donor-acceptor copolymer semiconductor layer is p-alkoxyphenyl-substituted thiadiazoloquinoline-thiophene, and the metal electrode layer is made of gold.

[0057] The preparation method of p-alkoxyphenyl-substituted thiadiazoloquinoline-thiophene is as follows: Dissolve p-alkoxyphenyl-substituted thiadiazoloquinoline-thiophene in a chlorobenzene solution with a concentration of 10 mg mL -1 ~ 15 mg mL -1 , and then spin-coat it on the lead-free perovskite layer at 2000 rpm for 60 s and anneal it at 90 °C for 30 min to obtain the donor-acceptor copolymer semiconductor layer.

[0058] The preparation methods of the remaining layers are the same as those in Example 1.

[0059] The structural formula of p-alkoxyphenyl-substituted thiadiazoloquinoline-thiophene is as follows:

[0060]

[0061] For the dual-functional bidirectional broadband optoelectronic response device provided in this Embodiment 4, under the room-temperature atmospheric environment, the opto-switching performance of the device under the illumination of visible light at 532 nm is respectively tested, and the negative optoelectronic detection performance at 532 nm can be seen; the opto-response postsynaptic current induced by two consecutive identical optical pulses with an interval of 2 s under the illumination of short-wave infrared light at 1550 nm is tested, and it can be seen that the photocurrent induced by the second optical pulse of the device is significantly higher than the first photocurrent, and there is an obvious synaptic double-pulse facilitation behavior, such as Figure 6a , Figure 6b as shown

[0062] This device is a two-terminal device with a vertical structure. The device is a dual-functional bidirectional broadband optoelectronic response device that realizes negative optoelectronic detection in visible light and positive opto-synaptic response in short-wave infrared light.

[0063] It should be understood that this solution is not limited to the above specific implementation manners. The devices and structures not described in detail should be understood to be implemented in a common manner in the art; any person skilled in the art can, without departing from the scope of the technical solution of this solution, make many possible changes and modifications to the technical solution of this solution by using the methods and technical contents disclosed above, or modify it into an equivalent embodiment with equivalent changes, which does not affect the essence of this solution. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of this solution without departing from the content of the technical solution of this solution still belong to the scope of protection of the technical solution of this solution.

Claims

1. A dual-function bidirectional wide spectrum photoelectric response device, characterized in that: It includes two layers of photoactive materials, a photoanode, a photocathode and a hole transport material layer, wherein the two layers of photoactive materials are a lead-free perovskite layer and a donor-acceptor copolymer semiconductor layer respectively; the photoanode is a transparent conductive electrode layer, and the photocathode is a metal electrode layer; the hole transport material layer is used to transport holes, block electrons, and modify the transparent conductive electrode layer; the structure of the photoelectric response device is arranged in sequence according to the transparent conductive electrode layer, the hole transport material layer, the lead-free perovskite layer, the donor-acceptor copolymer semiconductor layer, and the metal electrode layer; under different lighting conditions, the carrier transport and storage characteristics change, so that on the same device, the dual-functional bidirectional characteristics of negative light detection and positive light synapse simulation are exhibited.

2. The dual-function bidirectional wide-spectrum photoelectric response device according to claim 1, characterized in that: The transparent conductive electrode layer material is selected from one of ITO and FTO, and is prepared by magnetron sputtering, with a thickness of 130nm to 150nm.

3. The dual-function bidirectional wide-spectrum photoelectric response device according to claim 1, characterized in that: The hole transport material layer is a P-type semiconductor, used for transporting holes, blocking electrons, and modifying a transparent conductive electrode layer. It is made of an aqueous solution of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, and has a thickness of 30 nm to 40 nm.

4. The dual-function bidirectional wide-spectrum photoelectric response device according to claim 1, characterized in that: The lead-free perovskite layer is CsBi3I 10 , CsAgBiBr6 or CsBi3Br 10 One of them, with a thickness of 300nm~350nm.

5. The dual-function bidirectional wide spectrum photoelectric response device according to claim 1, characterized in that: The donor-acceptor copolymer semiconductor layer is one of polybenzobisthiadiazole-dithiophene cyclopentane, polybenzobisthiadiazole-dithiophene pyrrole or thiadiazole quinoline-thiophene substituted with p-alkoxybenzene, and has a thickness of 150 nm to 200 nm.

6. The dual-function bidirectional wide-spectrum photoelectric response device according to claim 1, characterized in that: The metal electrode layer is one of gold or silver, prepared by vacuum evaporation method, and has a thickness of 30 nm to 50 nm.

7. The dual-function bidirectional wide spectrum photoelectric response device according to any one of claims 1 to 6, characterized in that: The functions of negative light detection and positive light synapse are realized. The specific modulation method is: applying visible light to the device to realize the negative light detection function, and as the light intensity increases, the light response amplitude gradually increases; applying short-wave infrared light to the device to realize the positive light synapse function, and as the light stimulation increases, the device gradually realizes the transition from short-term memory to long-term memory.

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