A testing device and testing method based on CsPbBr3 nanosheet photodetector

Abstract

This invention discloses a testing device and method for a CsPbBr3 nanosheet photodetector. The testing device includes a CsPbBr3 nanosheet photodetector, a force-electric control platform, and a system tester. The CsPbBr3 nanosheet film forms a Schottky barrier with indium tin oxide (ITO) to separate photogenerated electron-hole pairs, thereby forming a photodetector with a high photoelectric effect. The CsPbBr3 nanosheet detector is mounted on the force-electric control platform and electrically connected to the system tester, which is electrically connected to a computer. A detection light source is positioned directly above the CsPbBr3 nanosheet photodetector. Based on semiconductor physics and piezoelectric optoelectronics theory, the invention establishes a multiscale physical model spanning the atomic, microscopic, and macroscopic scales to quantitatively describe the optical / mechanical / electrical coupling performance of the CsPbBr3 nanosheet photodetector.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano-photoelectric devices, and in particular relates to a light / force / electricity coupling test device based on a Schottky barrier type CsPbBr3 nanosheet photodetector and a test method thereof. Background Art

[0002] In recent years, metal halide perovskites (MHPs) (such as CsPbX3; X is I, Br, and CI) have unique electronic and optical properties and have garnered significant research interest in applications in next-generation photovoltaic and optoelectronic devices. Compared to bulk materials, two-dimensional perovskites exhibit a variety of interesting properties, including tunable band gaps, high photoconductivity gain, high luminescence efficiency, and nonlinear optical properties. Many of these properties are found to be strongly dependent on their thickness, and their ultrathin thickness enhances the sensitivity of these properties to applied electric fields. Furthermore, two-dimensional perovskites are ideal building blocks for the fabrication of flexible devices, as ultrathin, planar materials with ultrasmooth surfaces are highly compatible with flexible substrates. Consequently, due to their unique advantages, two-dimensional perovskites have attracted increasing research interest in flexible optoelectronic devices such as light-emitting diodes (LEDs), solar cells, and PDs.

[0003] In optoelectronic devices containing piezoelectric semiconductors, strain-induced piezoelectric charges and piezoelectric potential on the contact interface play a vital role in the separation and transport of carriers in the photoelectronic process, which is the working principle of the piezoelectric photoelectronic effect. In the past few years, the piezoelectric photoelectronic effect has been widely used in the field of optics for third-generation semiconductors and transition metal dichalcogenides such as ZnO, GaN and MoS2. Equally important, the piezoelectric effect has been detected in perovskite materials, and the influence of the piezoelectric effect on the optoelectronic properties of perovskite-based devices has been studied from the macroscopic to the atomic scale through experiments and theoretical calculations. At the macroscopic scale, the piezoelectric photoelectronic effect has been used to effectively improve the photocurrent, response and recovery speed of photodetectors based on CH3NH3PbI3 single crystals. The piezoelectric photoelectronic effect makes EA4Pb3Br 10The responsivity of two-dimensional perovskite photodetectors has been increased to 284%. At the microscale, the influence of the piezoelectric optoelectronic effect on the performance of CsPbBr3 microwire-based photodetectors was investigated by applying different tensile and compressive strains. The piezoelectric potential distribution was modeled using the finite element method to explore the underlying mechanism. At the atomic scale, density functional theory (DFT) calculations were performed to understand the mechanism by which the piezoelectric effect influences the performance of two-dimensional devices. For example, DFT calculations show that the piezoelectric coupling between monolayer BN and MoS2 and the wurtzite structure is stronger than that between the bulk materials. Furthermore, DFT and FEM simulations, spanning the atomic to microscale, identified piezoelectric charges at the MoS2 / metal-MoS2 interface. However, to our knowledge, a multiscale physical model spanning atomic, micro, and macroscales to quantitatively describe the optomechanical properties of two-dimensional perovskite optoelectronic devices is still lacking.

[0004] In view of the fact that there is currently no quantitative research on the optomechanical properties of two-dimensional perovskite optoelectronic devices and commercial photodetectors can only be tested photoelectrically, it is necessary to construct a light / force / electric coupling test device based on Schottky barrier type CsPbBr3 nanosheet photodetectors. Summary of the Invention

[0005] In order to overcome the above-mentioned technical deficiencies, the present invention provides a light / force / electricity coupling testing device and a testing method based on a Schottky barrier type CsPbBr3 nanosheet photodetector, thereby expanding the functions of the photodetector and truly reflecting the light / force / electricity coupling performance of micro-nano perovskite materials.

[0006] The technical solution of the present invention to solve the above technical problems is: a light / force / electric coupling testing device based on a Schottky barrier type CsPbBr3 nanosheet photodetector, including a force-electric control platform, a system tester, a detection light source and a laser focusing lens; a CsPbBr3 nanosheet photodetector is arranged on the force-electric control platform, and the detection light source is arranged directly above the CsPbBr3 nanosheet photodetector; the detection light source is connected to the laser focusing lens, the CsPbBr3 nanosheet photodetector is electrically connected to the system tester, and the system tester is electrically connected to a computer.

[0007] Furthermore, the CsPbBr3 nanosheet photodetector includes a flexible substrate, an electrode, and a photoelectric sensitive material light absorption layer connected in sequence.

[0008] Furthermore, the preparation method of the CsPbBr3 nanosheet photodetector comprises the following steps:

[0009] S1: Preparation of CsPbBr3 nanosheet dispersion;

[0010] S2: Assemble the CsPbBr3 nanosheets dispersion into a thin film on an ITO / polyethylene terephthalate substrate by drop casting.

[0011] S3: placing the assembled film in air until all organic solvents are completely evaporated;

[0012] S4: applying silver paste and conductive carbon paste to the electrodes in sequence to obtain a chip;

[0013] S5: Connect the prepared chip to the pins of a standard TO-5 tube shell, and then glue the tube cap to the base to complete the preparation of the photodetector.

[0014] Furthermore, the preparation method of the Schottky barrier type CsPbBr3 nanosheet photodetector is as follows:

[0015] 1) Add 0.05-0.1 g of cesium carbonate powder to a three-necked flask containing 5-10 ml of oleic acid and dry at 110-120° C. for 0.5-1 h until the cesium carbonate and oleic acid react completely to obtain cesium oleate;

[0016] 2) Add 0.25-0.5 ml of oleic acid, 0.25-0.5 ml of oleylamine, 0.45-0.9 ml of octanoic acid, and 0.45-0.9 ml of octylamine to 10-20 ml of octadecene, and add 0.04-0.08 g of lead bromide powder, and stir under vacuum at 110-120° C. for 0.5-1 hour until the powder is dissolved to obtain a mixed solution;

[0017] 3) In step 2), the temperature of the mixed solution was raised to 145-150° C. under vacuum, 1-2 ml of cesium oleate cooled to room temperature was quickly added, and the mixture was reacted for 5-8 seconds, and heated at 125-130° C. for 3-3.5 minutes. The reacted solution was then transferred to an ice-water bath for cooling;

[0018] 4) Add 10-20 ml of n-hexane to the mixed solution cooled to room temperature, transfer to a 50 ml centrifuge tube, and centrifuge at 3000-3500 rpm for 5-8 minutes;

[0019] 5) Pour off the upper liquid, add 10-20 ml of n-hexane and repeat step 4), add 10-20 ml of n-hexane to obtain a CsPbBr3 nanosheet dispersion;

[0020] 6) assembling a thin film of CsPbBr3 nanosheet dispersion on an ITO / polyethylene terephthalate (PET) substrate by a drop casting method;

[0021] 7) placing the assembled film in air until all organic solvents are completely evaporated; applying silver paste and conductive carbon paste to the electrodes in sequence to obtain a chip;

[0022] 8) Connect the prepared chip to the pins of a standard TO-5 tube shell, and then glue the tube cap to the base to complete the preparation of the photodetector.

[0023] Furthermore, the electrode spacing of the CsPbBr3 nanosheet photodetector is 2-3 mm, and the length is 7-8 mm; preferably, the electrode spacing is 2 mm, and the length is 7 mm.

[0024] A testing method for a light / force / electricity coupling testing device based on a Schottky barrier type CsPbBr3 nanosheet photodetector comprises the following steps:

[0025] A1: Place the CsPbBr3 nanosheet photodetector on a mechanoelectric control platform, and connect its electrodes to the system tester;

[0026] A2: The electromechanical control platform applies force and voltage to the CsPbBr3 nanosheet photodetector and illuminates the CsPbBr3 nanosheet photodetector with a detection light source;

[0027] A3: Read the strain s by connecting the computer of optical / mechanical / electrical coupling test device 11 , and the applied voltage U, and substituted into formula (1), the current density of the photodetector under the conditions of force and light is obtained:

[0028]

[0029] In the above formula: A is the Richardson-Dussmann constant, τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, υ is the photon frequency, Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, w piezo is the piezoelectric charge width, ε s is the relative dielectric constant.

[0030] Theoretical model of the optical / mechanical / electrical coupling test device and its test method based on Schottky barrier CsPbBr3 nanosheet photodetector:

[0031] According to the DFT calculation results, the piezoelectric constant e was obtained. 11 and the piezoelectric charge width w piezo These parameters can quantitatively describe the relationship between strain, polarization and potential barrier. The total emission current density is:

[0032]

[0033] Where: A is the Richardson-Dussmann constant, E Fn and E FTo prepare dense energy levels and intrinsic Fermi levels.

[0034] According to semiconductor physics, the relationship between carrier concentration and Fermi level can be expressed as:

[0035]

[0036] Where: n is the electron concentration, n i is the intrinsic carrier concentration.

[0037] Based on the theory of semiconductor physics and piezoelectric optoelectronics, a theoretical model for photoelectric coupling testing is derived: the non-equilibrium carrier concentration under light conditions is derived from the continuity equation:

[0038]

[0039] Where: τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, and υ is the photon frequency.

[0040] Substituting the above two equations into equation (1), we get:

[0041]

[0042] This equation can be used to relate the current generated by different strains under light to the potential barrier. According to piezoelectric theory, the change in the effective Schottky barrier height caused by the piezoelectric charge can be obtained from the potential distribution:

[0043] Where: Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, w piezo is the piezoelectric charge width, ε s is the relative dielectric constant.

[0044] Therefore, we can refine the above formula into a formula combining light, force, and electricity, thereby obtaining the theoretical model of the light / force / electricity coupling test device based on Schottky barrier type CsPbBr3 nanosheet photodetector:

[0045]

[0046] In the above formula: A is the Richardson-Dussmann constant, τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, υ is the photon frequency, Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, wpiezo is the piezoelectric charge width, ε s is the relative dielectric constant.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. Based on the theory of semiconductor physics and piezoelectric optoelectronics, this paper constructs for the first time a light / force / electric coupling test device based on a Schottky barrier-type CsPbBr3 nanosheet photodetector, and constructs a multi-scale physical model spanning atomic, microscopic, and macroscopic scales to quantitatively describe the light / force / electric coupling performance of the CsPbBr3 nanosheet photodetector.

[0049] 2. This invention establishes a cross-scale model that links the microscopic and macroscopic aspects, quantitatively determining the relationship between strain, polarization, and potential barriers. This provides a basis for the optimized design of high-performance optoelectronic devices under strain. It holds the potential to extend the strategy of modulating optoelectronic behavior using the piezoelectric photoelectric effect to other metal halide perovskite-based optoelectronic devices, including solar cells and light-emitting diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of the structure of the testing device in the present invention;

[0051] Figure 2 Schematic diagram of the Schottky barrier type CsPbBr3 nanosheet photodetector of the present invention;

[0052] Figure 3 This is a surface SEM image of a Schottky barrier type CsPbBr3 nanosheet photodetector prepared in an embodiment of the present invention;

[0053] Figure 4 This is a cross-sectional SEM image of a Schottky barrier-type CsPbBr3 nanosheet photodetector prepared in an embodiment of the present invention.

[0054] Figure 5 This is an IV curve of a Schottky barrier type CsPbBr3 nanosheet photodetector prepared in an embodiment of the present invention;

[0055] Figure 6 This is an IT curve of a Schottky barrier type CsPbBr3 nanosheet photodetector prepared in an embodiment of the present invention; DETAILED DESCRIPTION

[0056] In order to clearly express the objectives, technical solutions and advantages of the present invention, the present invention will be further described below with reference to the accompanying drawings and specific implementation methods.

[0057] See also Figure 1 , Figure 1This is a schematic diagram of the structure of a light / force / electric coupling test device based on a Schottky barrier-type CsPbBr3 nanosheet photodetector. The test device includes a light / force / electric coupling detection station, a system tester 5, a detection light source 3, and a laser focusing lens 4. The detection light source 3 is positioned directly above the CsPbBr3 nanosheet photodetector 2. The light / force / electric coupling detection station includes the CsPbBr3 nanosheet detector 2 and a force-electric control platform 1, which is used to introduce optical signals to the force-electric control platform 1. The CsPbBr3 nanosheet detector 2 is positioned on the force-electric control platform 1 and is electrically connected to the system tester 5. The system tester 5 is electrically connected to the computer, and the computer contains the operating software of the test method of the present invention. Start the system tester 5, connect it to the computer, clamp the counter electrode and reference electrode on the electromechanical control platform 1 to one end of the CsPbBr3 nanosheet detector 2 at the same time, and clamp the working electrode to the other end of the CsPbBr3 nanosheet detector 2. After the system tester 5 is electrically connected to the computer, perform hardware testing, select the test method in the computer, set the parameters, click Run, and complete the scanning test.

[0058] See also Figure 2 In the Schottky barrier type CsPbBr3 nanosheet photodetector of this embodiment, a CsPbBr3 thin film is obtained by drop-casting on an ITO / polyethylene terephthalate (PET) substrate. The CsPbBr3 thin film and ITO form a Schottky barrier, thereby constituting a photodetector with strong light response.

[0059] The preparation method of the Schottky barrier type CsPbBr3 nanosheet photodetector of this embodiment is as follows:

[0060] 1) Add 0.1 g of cesium carbonate powder to a three-necked flask containing 10 ml of oleic acid and dry at 120°C for 1 h until the cesium carbonate and oleic acid react completely to obtain cesium oleate;

[0061] 2) Add 0.5 ml of oleic acid, 0.5 ml of oleylamine, 0.9 ml of octanoic acid, and 0.9 ml of octylamine to 20 ml of octadecene, and add 0.08 g of lead bromide powder. Stir under vacuum at 120°C for 0.5 h until the powder dissolves to obtain a mixed solution;

[0062] 3) In step 2), the temperature of the mixed solution was raised to 150° C. under vacuum, and 2 ml of cesium oleate cooled to room temperature was quickly added and reacted for 5 seconds. The mixture was then heated at 130° C. for 3 minutes, and the reacted solution was then transferred to an ice-water bath for cooling;

[0063] 4) Add 20 ml of n-hexane to the mixed solution cooled to room temperature, transfer to a 50 ml centrifuge tube, and centrifuge at 3500 rpm for 5 min;

[0064] 5) Pour off the upper layer of liquid, add 20 ml of n-hexane and repeat step 4), add 20 ml of n-hexane to obtain a CsPbBr3 nanosheet dispersion;

[0065] 6) Assembling a thin film of CsPbBr3 nanosheet dispersion on an ITO / polyethylene terephthalate (PET) substrate by drop casting; the electrode spacing is about 2 mm and the length is about 7 mm;

[0066] 7) placing the assembled film in air until all organic solvents are completely evaporated; applying silver paste and conductive carbon paste to the electrodes in sequence to obtain a chip;

[0067] 8) Connect the prepared chip to the pins of a standard TO-5 tube shell, and then glue the tube cap to the base to complete the preparation of the photodetector;

[0068] Figure 3 The photodetector obtained in the embodiment has a power output of 7.19, 31.80 and 233.50 μW cm in darkness and 450 nm light, respectively. -2 The IV curves were obtained under the light intensity of 7.19 μW cm. When the laser is turned on, the photocurrent increases sharply with the increase of applied voltage due to the increase of carrier drift velocity. -2 increased to 233.50 μW cm -2 .

[0069] Figure 4 The IT curves of the photodetector obtained for this example were measured at a 5V bias in the dark and using a laser diode at 450nm with intensities of 7.19, 31.80, and 233.50 μW cm -2 , controlled by a light shutter in darkness and light.

[0070] Figure 5 This is a SEM image of the flexible photodetector produced in this example, showing a uniform coating of the synthesized two-dimensional CsPbBr3 on the substrate. The synthesized two-dimensional CsPbBr3 nanosheets exhibit high dispersibility, making them ideal for optoelectronic applications. Furthermore, the high-density, crack-free nanosheet film facilitates the transport of photogenerated carriers along the plane of the two-dimensional sheet, potentially leading to high optoelectronic performance.

[0071] Figure 6 This is a SEM cross-sectional image of the flexible photodetector obtained in this example. The two-dimensional CsPbBr3 single-chain fluorescence (scf) marked in cyan is used as a photodetector, and its uniform thickness is about 6.6μm, much smaller than the ITO / PET marked in brown.

[0072] A testing method using the above-mentioned light / force / electricity coupling testing device based on Schottky barrier type CsPbBr3 nanosheet photodetector comprises the following steps:

[0073] 1) Place the CsPbBr3 nanosheet photodetector on a mechanoelectric control platform, where the electrodes are connected to a system tester;

[0074] 2) Using the force-electric control platform of the light / force / electric coupling detection station to apply force and voltage to the CsPbBr3 nanosheet photodetector, and turning on the detection light source to apply light to the CsPbBr3 nanosheet photodetector;

[0075] 3) Read the strain s through a computer connected to the optical / mechanical / electrical coupling test device 11 , apply voltage U, and substitute it into formula (1) to obtain the current density of the photodetector under the conditions of force and light, and then quantitatively study the light / force / electricity coupling relationship of micro-nano semiconductor materials:

[0076]

[0077] In the above formula: A is the Richardson-Dussmann constant, τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, υ is the photon frequency, Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, w piezo is the piezoelectric charge width, ε s is the relative dielectric constant.

[0078] The derivation process of formula (1) is as follows:

[0079] A31: According to the DFT calculation results, the piezoelectric constant e is obtained 11 and the piezoelectric charge width w piezo ; The total emission current density is:

[0080]

[0081] Where: A is the Richardson-Dussmann constant, E Fn and E F To prepare dense energy levels and intrinsic Fermi levels;

[0082] A32: According to semiconductor physics, the relationship between carrier concentration and Fermi level can be expressed as:

[0083]

[0084] Where: n is the electron concentration, n i is the intrinsic carrier concentration;

[0085] A33: Based on the theory of semiconductor physics and piezoelectric optoelectronics, a theoretical model for photoelectric coupling testing was derived, and the non-equilibrium carrier concentration under light conditions was derived from the continuity equation:

[0086]

[0087] Where: τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, and υ is the photon frequency.

[0088] A34: Substituting the above two equations into equation (2), we obtain:

[0089]

[0090] A35: This equation can be used to relate the current generated by different strains under illumination to the potential barrier; according to piezoelectric theory, the change in the effective Schottky barrier height caused by the piezoelectric charge can be obtained from the potential distribution:

[0091] Where: Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, w piezo is the piezoelectric charge width, ε s is the relative dielectric constant;

[0092] A36: Refining the above formula into a formula combining light, force, and electricity, we obtain the theoretical model of the light / force / electricity coupling test device based on Schottky barrier type CsPbBr3 nanosheet photodetector:

[0093]

[0094] This document describes the principles and implementation methods of the present invention. The above device description is only intended to help understand the method and core ideas of the present invention. At the same time, those skilled in the art may make changes to the specific implementation methods and application scope based on the ideas of the present invention. In summary, the contents of this specification should not be understood as limiting the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A test method for a light / force / electric coupling test device based on a Schottky barrier type CsPbBr3 nanosheet photodetector, characterized in that The following steps are involved: A1: Place the CsPbBr3 nanosheet photodetector on a mechanoelectric control platform, and connect its electrodes to the system tester; A2: The electromechanical control platform applies force and voltage to the CsPbBr3 nanosheet photodetector and illuminates the CsPbBr3 nanosheet photodetector with a detection light source; A3: Read the strain s applied to the device through a computer connected to the optical / mechanical / electrical coupling test device 11 , and the applied voltage U, and substituted into formula (1), the current density of the photodetector under the conditions of force and light is obtained: （1） In the above formula: A is the Richardson-Dussmann constant, τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, υ is the photon frequency, Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, w piezo is the piezoelectric charge width, ε s is the relative dielectric constant, e 11 is the piezoelectric coefficient; T is the temperature, k is the Boltzmann constant; n is the electron concentration; The optical / mechanical / electrical coupling test device includes a mechanical and electrical control platform, a system tester, a detection light source and a laser focusing lens; A CsPbBr3 nanosheet photodetector is set on the electromechanical control platform, and a detection light source is set directly above the CsPbBr3 nanosheet photodetector; the detection light source is connected to a laser focusing lens, the CsPbBr3 nanosheet photodetector is electrically connected to a system tester, and the system tester is electrically connected to a computer.

2. The testing method of the light / force / electric coupling testing device based on the Schottky barrier type CsPbBr3 nanosheet photodetector according to claim 1 is characterized in that: The CsPbBr3 nanosheet photoelectric detector comprises a flexible substrate, an electrode and a photoelectric sensitive material light absorption layer which are connected in sequence.

3. The test method of the light / force / electric coupling test device based on the Schottky barrier type CsPbBr3 nanosheet photodetector according to claim 2, characterized in that: The method for preparing the CsPbBr3 nanosheet photodetector comprises the following steps: S1: Preparation of CsPbBr3 nanosheet dispersion; S2: Assemble the CsPbBr3 nanosheets dispersion into a thin film on an ITO / polyethylene terephthalate substrate by drop casting. S3: placing the assembled film in air until all organic solvents are completely evaporated; S4: applying silver paste and conductive carbon paste to the electrodes in sequence to obtain a chip; S5: Connect the prepared chip to the pins of a standard TO-5 tube shell, and then glue the tube cap to the base to complete the preparation of the photodetector.

4. The testing method of the light / force / electric coupling testing device based on the Schottky barrier type CsPbBr3 nanosheet photodetector according to claim 2, characterized in that: The method for preparing the CsPbBr3 nanosheet photodetector comprises the following steps: 1) Add 0.05-0.1g of cesium carbonate powder to a three-necked flask containing 5-10ml of oleic acid and dry at 110-120°C for 0.5-1h until the cesium carbonate and oleic acid react completely to obtain cesium oleate; 2) Add 0.25-0.5 ml of oleic acid, 0.25-0.5 ml of oleylamine, 0.45-0.9 ml of octanoic acid, and 0.45-0.9 ml of octylamine to 10-20 ml of octadecene, and add 0.04-0.08 g of lead bromide powder. Stir under vacuum at 110-120°C for 0.5-1 hour until the powder dissolves to obtain a mixed solution. 3) In step 2), the temperature of the mixed solution was raised to 145-150°C under vacuum, 1-2 ml of cesium oleate cooled to room temperature was quickly added, and the mixture was reacted for 5-8 seconds. The mixture was then heated at 125-130°C for 3-3.5 minutes, and the reacted solution was then transferred to an ice-water bath for cooling; 4) Add 10-20 ml of n-hexane to the mixed solution cooled to room temperature, transfer it to a 50 ml centrifuge tube, and centrifuge at 3000-3500 rpm for 5-8 minutes; 5) Pour off the upper liquid, add 10-20 ml of n-hexane and repeat step 4), add 10-20 ml of n-hexane to obtain a CsPbBr3 nanosheet dispersion; 6) The CsPbBr3 nanosheet dispersion was assembled into a thin film on an ITO / polyethylene terephthalate (PET) substrate by a drop casting method; 7) The assembled film is placed in air until all organic solvents are completely evaporated; silver paste and conductive carbon paste are applied to the electrodes in sequence to obtain a chip; 8) Connect the prepared chip to the pins of a standard TO-5 tube shell, and then glue the tube cap to the base to complete the preparation of the photodetector.

5. The testing method of the light / force / electric coupling testing device based on the Schottky barrier type CsPbBr3 nanosheet photodetector according to claim 2, characterized in that: The electrode spacing of the CsPbBr3 nanosheet photodetector is 2-3 mm and the length is 7-8 mm.

6. The method for testing the optical / mechanical / electrical coupling test device based on the Schottky barrier type CsPbBr3 nanosheet photodetector according to claim 1, characterized in that: The derivation process of the formula in step A3 is as follows: A31: According to the DFT calculation results, the piezoelectric coefficient e is obtained 11 and the piezoelectric charge width w piezo ; The total emission current density is: （2） Where: A is the Richardson-Dussmann constant, E Fn and E F To prepare the dense level and intrinsic Fermi level, φns is the Schottky barrier; T is the temperature, k is the Boltzmann constant; A32: According to semiconductor physics, the relationship between carrier concentration and Fermi level is expressed as: （3） Where: n is the electron concentration, n i is the intrinsic carrier concentration; A33: Based on the theory of semiconductor physics and piezoelectric optoelectronics, a theoretical model for photoelectric coupling testing was derived, and the non-equilibrium carrier concentration under light conditions was derived from the continuity equation: （4） Where: τ n is the carrier lifetime, η is the quantum efficiency, V is the material volume, P is the laser output power, h is the Planck constant, and υ is the photon frequency; A34: Substituting formula (3) and formula (4) into formula (2), we obtain: （5） A35: The above formula (5) can be used to relate the current generated by different strains under illumination to the potential barrier; according to piezoelectric theory, the change in the effective Schottky barrier height caused by the piezoelectric charge can be obtained from the potential distribution: （6） Where: Φ ns0 is the Schottky barrier under no strain, q is the charge of a single electron, s 11 is the applied strain, w piezo is the piezoelectric charge width, ε s is the relative dielectric constant; A36: Refining the above formula into a formula combining light, force, and electricity, we obtain the theoretical model of the light / force / electricity coupling test device based on Schottky barrier type CsPbBr3 nanosheet photodetector: （1）。

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