A 2D perovskite-based ultraviolet photodetector

Abstract

The present invention relates to a photodetector prepared from a two-dimensional perovskite material. The photodetector includes, from bottom to top, a transparent conductive glass substrate, a hole transport layer, a two-dimensional perovskite active layer (A)<subgt;2< / subgt;(B)<subgt;n-1< / subgt;Pb<subgt;n< / subgt;Cl<subgt;3n+1< / subgt;, an electron transport layer, a hole blocking layer, an anti-corrosion metal layer, and a counter electrode metal. The present invention can significantly improve the stability of the device, reduce the dark current of the device, thereby enhancing the detectivity of the device, and has good application prospects in the future.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic detection of novel semiconductor materials. Specifically, it relates to a class of two-dimensional perovskite materials for optoelectronic detection and a preparation method for optoelectronic detectors thereof. Background Art

[0002] The principle of an optoelectronic detector is to utilize the interaction between light and matter to collect light of a specific wavelength and convert it into an electrical signal that can be measured. It has a wide range of applications in fields such as agriculture, industry, and military, such as imaging, optical communication, environmental monitoring, space exploration, etc. Since organic-inorganic hybrid perovskites began to be used as visible sensitizers in photovoltaic cells, groundbreaking progress has been continuously made in the past decade, and the conversion efficiency of perovskite solar cells has been continuously improved. Due to the excellent optoelectronic properties of perovskites, extensive research has also been carried out in the aspect of optoelectronic detectors, and a series of good results have been achieved.

[0003] Organic-inorganic hybrid perovskites have received a lot of research due to a series of good optoelectronic properties such as high carrier mobility, large light absorption coefficient, long carrier diffusion length, and tunable direct bandgap. Perovskite materials are very suitable for applications in optoelectronic conversion devices such as solar cells, light-emitting diodes, lasers, and optoelectronic detectors due to their excellent optoelectronic properties. So far, visible and ultraviolet optoelectronic detectors have been realized on polycrystalline thin films, nanostructures, and bulk single-crystalline perovskite materials, and obvious progress has been made in device performance and related physical mechanisms.

[0004] Ultraviolet detectors prepared from organic-inorganic hybrid perovskite materials have very broad application prospects in civil and military fields and have now become a new research hotspot in the field of semiconductor ultraviolet optoelectronic detectors. Three-dimensional perovskite CH3NH3PbCl3 is a semiconductor material with a relatively wide bandgap in the perovskite system, and its bandgap at room temperature is about 3.1 eV, which is very suitable for preparing ultraviolet optoelectronic detectors. Although there have been some reports on CH3NH3PbCl3 ultraviolet optoelectronic detectors, the research in this aspect is still in its infancy. The main problems faced by the current material CH3NH3PbCl3 and its application in ultraviolet optoelectronic detectors are: high density of intrinsic defects in the material; low responsivity and large dark current of the device; poor stability of device performance; lack of high-quality structure devices, etc. Summary of the Invention

[0005] The object of the present invention is to invent an ultraviolet optoelectronic detector based on two-dimensional perovskite for the problem that perovskite optoelectronic detectors in the prior art have poor long-term stability and fast attenuation rate when placed in air and cannot be effectively commercialized. This detector uses a two-dimensional RP-phase perovskite material (A)2(B) n-1 Pb n Cl3n+1 As an active layer to prepare a photodetector, a two-dimensional RP-phase perovskite (A)2(B) is used in the preparation n-1 Pb n Cl 3n+1 precursor solution, and a long-chain chloride organic ammonium salt (ACl) is added, and a high-quality perovskite film is obtained through low-pressure assisted treatment. The photodetector based on this film can significantly improve the stability of the device, reduce the dark current of the device, thereby improving the detection rate of the device, and has good application prospects in the future.

[0006] The technical solution of the present invention is as follows:

[0007] A photodetector prepared from a two-dimensional perovskite material, which from bottom to top is successively a transparent conductive glass substrate, a hole transport layer, a two-dimensional perovskite active layer (A)2(B) n-1 Pb n Cl 3n+1 , an electron transport layer, a hole blocking layer, an anti-corrosion metal layer, and a counter electrode metal.

[0008] Furthermore, the thickness of the hole blocking layer is 1-50 nm, the thickness of the electron transport layer is 5-100 nm, the thickness of the perovskite active layer is 100-500 nm, the thickness of the hole transport layer is 5-100 nm, and the thickness of the anti-corrosion layer is 1-10 nm.

[0009] The substrate is preferably ITO conductive glass, and the resistance of ITO is 5-30 Ω.

[0010] The perovskite active layer film is a two-dimensional perovskite material, and its general formula is (A)2(B) n-1 Pb n Cl 3n+1 , and its A-site cation is PMA + (C6H5CH2NH3 + ), PEA + (C6H5(CH2)2NH3 + ), BA + (CH3(CH2)3NH3 + ), 5AVA + (HOOC(CH2)4NH3 + ), 3APA + (H00C(CH2)2NH3 + ), CH3CH2CH2NH3 + , CH(CH3)2CH2NH3 + , C(CH3)3NH3 + , CH3(CH2)4NH3 + , CH3(CH2)11 NH3 + ); The B-site cation is MA + (CH3NH3 + ), FA + (NH2CH=NH2 + ), or Cs + .

[0011] The value of n is 1 - 60.

[0012] The counter electrode metal is gold, silver, copper or aluminum.

[0013] The anti-corrosion metal is bismuth or chromium.

[0014] The hole transport layer is at least one of 2,2',7,7'-tetrakis(diphenylamino)-9,9'-spirobifluorene (Spiro), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly-3-hexylthiophene (P3HT), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), molybdenum trioxide, nickel oxide, cuprous iodide, cuprous thiocyanate, copper phthalocyanine, chromium oxide.

[0015] The electron transport layer is at least one of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), carbon 60 (C60), zinc oxide nanoparticles, tin dioxide nanoparticles.

[0016] The hole blocking layer is polyethyleneimine (PEI), Cr2O X , 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorene-2,7-diyl)-alt-[(9,9-dioctylfluorene-2,7-diyl)(PFN) one of them.

[0017] The method for preparing a photodetector using a two-dimensional perovskite material includes the following steps:

[0018] (1) Pretreat the substrate:

[0019] Ultrasonically clean the substrate with a glass cleaner, deionized water and ethanol solution for 10 - 30 minutes respectively, then dry it in a nitrogen environment, and finally treat it in a UV - Ozone machine for 15 - 30 minutes;

[0020] (2) Fabricate a hole transport layer on the substrate:

[0021] Put the cleaned ITO glass substrate into a vacuum chamber, and wait until the vacuum value is pumped to 6×10 -4When the pressure is below Pa, deposit the hole transport layer material onto the substrate by electron beam;

[0022] (3) Prepare the perovskite light absorption layer:

[0023] According to the molar ratio of A:B:Pb:Cl = 2:(n - 1):n:(3n + 1), add ACl, BCl, and PbCl₂ into the solvent to obtain a perovskite precursor solution with a concentration of 0.2 - 1.5 mol / L; spin-coat the prepared perovskite precursor solution onto the hole transport layer, with the rotation speed of the spin coater being 3000 - 6000 rpm, and then obtain a 100 - 400 nm thin film through low-pressure assisted treatment, where the pressure during the low-pressure assisted treatment is 1 - 500 Pa, and then perform annealing treatment on a heating stage, with the annealing temperature being 70 - 110 °C and the annealing time being 5 - 20 min; the concentration of the precursor solution is calculated based on the content of Pb;

[0024] The long-chain chloride organic ammonium salt (ACl) is C₆H₅CH₂NH₃Cl, C₆H₅(CH₂)₂NH₃Cl, CH₃(CH₂)₃NH₃Cl, HOOC(CH₂)₄NH₃Cl, H00C(CH₂)₂NH₃Cl, CH₃CH₂CH₂NH₃Cl, CH(CH₃)₂CH₂NH₃Cl, C(CH₃)₃NH₃Cl, CH₃(CH₂)₄NH₃Cl or CH₃(CH₂) 11 NH₃Cl.

[0025] The BCl is CH₃NH₃Cl, NH₂CH=NH₂Cl or CsCl;

[0026] The solvent is one or more of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc);

[0027] (4) Prepare the electron transport layer:

[0028] Spin-coat the electron transport layer solution onto the surface of the perovskite thin film, and obtain the electron transport layer by controlling the rotation speed of the spin coater (1000 - 3000 rpm); the thickness is 30 - 50 nm;

[0029] The concentration of the electron transport layer solution is 10 - 40 mg / mL;

[0030] (5) Prepare the hole blocking layer:

[0031] Spin-coat the hole blocking layer solution onto the surface of the electron transport layer, and obtain the hole blocking layer by controlling the rotation speed of the spin coater (2000 - 6000 rpm); the thickness is 20 - 50 nm;

[0032] The concentration of the hole blocking layer solution is 0.2 - 1.5 mg / mL;

[0033] (6) Prepare the metal counter electrode:

[0034] Place the device obtained in step (5) into a high-resistance vacuum coating instrument. After the chamber vacuum reaches 10 -4 -10 -5 Pa, heat the electrode. First deposit the anti-corrosion metal, and then continuously deposit the metal counter electrode on the anti-corrosion metal to complete the preparation of the entire photodetector, and finally obtain a photodetector prepared from a two-dimensional perovskite material.

[0035] The two-dimensional perovskite thin film in step (3) is prepared by the low-pressure assisted method, and the pressure is 1 - 500 Pa.

[0036] The evaporation rate of the deposition in step (6) is 0.03 - 0.08 nm / s.

[0037] The beneficial effects of the present invention are:

[0038] 1. The two-dimensional RP-phase perovskite material (A)2(B) n-1 Pb n Cl 3n+1 provided by the present invention has good stability and a low defect state density, and is a preferred material for preparing optoelectronic devices.

[0039] 2. The stability of the inverted planar structure ultraviolet photodetector prepared based on the two-dimensional RP-phase perovskite material (A)2(B) n-1 Pb n Cl 3n+1 is significantly improved compared with that of the three-dimensional perovskite (after 800 hours, the photocurrent of the ultraviolet detector based on the two-dimensional RP-phase can maintain 67% of the initial value, while the photocurrent of the detector based on the three-dimensional perovskite is only 20% of the initial value, see Figure 7 ) from 100 hours to 800 hours. The dark current of the device is reduced by two orders of magnitude compared with that of the three-dimensional perovskite (see Figure 5 ), and the detectivity is increased by 2 times compared with that of the three-dimensional perovskite (see Figure 6 ). Description of the Drawings

[0040] Figure 1 is a schematic structural diagram of the photodetector described in the present invention;

[0041] Figure 2 is a scanning electron microscope image of the two-dimensional perovskite thin film prepared in Example 1;

[0042] Figure 3The photocurrent and dark current characteristics of the two-dimensional perovskite photodetector obtained in Example 1;

[0043] Figure 4 The switching characteristics of the two-dimensional perovskite photodetector obtained in Example 1;

[0044] Figure 5 The dark current comparison chart of the two-dimensional perovskite photodetector and the three-dimensional perovskite photodetector obtained in Example 1;

[0045] Figure 6 The detectivity comparison chart of the two-dimensional perovskite photodetector and the three-dimensional perovskite photodetector obtained in Example 1;

[0046] Figure 7 The stability comparison chart of the two-dimensional perovskite photodetector and the three-dimensional perovskite photodetector obtained in Example 1.

[0047] Among them, 1 - transparent conductive glass substrate, 2 - hole transport layer, 3 - two-dimensional perovskite active layer (A)2(B) n- 1Pb n Cl 3n+1 、4 - electron transport layer, 5 - hole blocking layer, 6 - anti-corrosion layer, 7 - metal counter electrode silver. Detailed implementation manners

[0048] The following examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention to the scope of the described examples.

[0049] Example 1

[0050] Two-dimensional perovskite material (PMA)2(MA)2Pb3Cl 10 Photodetector device

[0051] The photodetector shown uses the two-dimensional perovskite material (PMA)2(MA)2Pb3Cl 10 Prepared photodetector, from top to bottom are metal counter electrode silver (Ag) 7 and metal bismuth (Bi) 6, hole blocking layer (BCP) 5, electron transport layer (PCBM) 4, perovskite active layer (PMA)2(MA)2Pb3Cl 10 3, hole transport layer (NiO) 2 and ITO conductive glass substrate 1, as Figure 1 shown. The thickness of the hole blocking layer is 8 nm, the thickness of the electron transport layer is 50 nm, the thickness of the perovskite active layer is 300 nm, the thickness of the hole transport layer is 30 nm, and the thickness of the ITO transparent conductive substrate is 110 nm. The preparation process is as follows:

[0052] (1) Preparation of transparent conductive glass substrate: The ITO transparent conductive glass substrate used in this example has an average transmittance of 88%. The ITO substrate was ultrasonically cleaned with glass cleaner, deionized water, and ethanol for 30 minutes respectively, then dried in a nitrogen atmosphere, and finally treated in a UV - Ozone machine for 30 minutes. The entire process cleans the substrate surface and increases the substrate work function.

[0053] (2) Place the cleaned ITO glass substrate into a vacuum chamber. When the vacuum value is pumped down to below 6×10 -4 Pa, deposit nickel oxide (NiO) onto the ITO substrate by electron beam to obtain a hole - transport layer with a thickness of 30 nm.

[0054] (3) Preparation of perovskite light - absorbing layer: Use the method of "spin - coating + low - pressure assisted treatment" to prepare a (PMA)2(MA)2Pb3Cl 10 light - absorbing layer thin film. The specific process is as follows: on the ITO / NiO substrate, first spin - coat the prepared perovskite precursor solution (with a concentration of 1 mol / L, specifically including solutes PMACl, MACl, PbCl2 with concentrations of 0.67 mol / L, 0.67 mol / L, and 1 mol / L respectively, and the solvent is a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of 1:1) at a speed of 4000 rpm by a spin coater, then perform low - pressure assisted treatment (vacuum degree is 10 Pa), and then place it on a heating stage for annealing at 90 °C for 10 min to obtain a perovskite thin - film absorbing layer with a thickness of 300 nm;

[0055] The scanning electron microscope photograph of the prepared perovskite thin film is as Figure 2 shown. It can be seen from the figure that the prepared two - dimensional perovskite thin film is dense and pore - free, which is beneficial to reducing the dark current of the device and thus improving the detectivity of the device.

[0056] (4) Preparation of electron - transport layer: Spin - coat the pre - prepared chlorobenzene solution of PCBM (20 mg / mL) onto the perovskite layer. By controlling the rotation speed of the spin coater and the dropping amount of the electron - transport layer, the electron - transport layer is controlled to be about 50 nm.

[0057] (5) Preparation of hole - blocking layer: Prepare a 0.8 mg / mL solution of PEI / IPA (isopropanol). By controlling the rotation speed of the spin coater at 3000 rpm and the dropping amount, spin - coat the solution on the surface of the electron - transport layer to obtain an 8 - nm thin film.

[0058] (6) Preparation of metal counter electrode: Place the device into a high - resistance vacuum coating instrument. When the chamber vacuum degree reaches 10 -4After Pa, heat the electrode and deposit 5 nm of metallic bismuth (Bi) at an evaporation rate of 0.04 nm / s. Then, use a mask to control the effective area of the electrode to 0.04 cm 2 Deposit a 100-nm-thick Ag electrode. The distance between the substrate and the evaporation source is 30 cm to complete the fabrication of the photodetector. The structure of the device is ITO / NiO / (PMA)2(MA) n-1 Pb n Cl 3n+1 / PCBM / BCP / Bi / Ag. The photocurrent and dark current of the ultraviolet detector based on this structure are as Figure 3 shown. It can be seen from the figure that the dark current of the detector can reach 5×10 -8 mA / cm 2 without bias voltage, and the photocurrent is 10 -4 mA / cm 2 , where the dark current is significantly lower than that of the reported three-dimensional perovskite detectors. The optical switching response characteristics of the device are as Figure 4 shown. It can be seen that the detectors based on two-dimensional perovskites exhibit good repeatability after 10 cycles of optical switching tests, indicating that the device has good stability. The comparison of the dark current of the two-dimensional perovskite ultraviolet detector prepared in this example with that of the three-dimensional perovskite detector prepared with the same structure is as Figure 5 shown. It can be seen that the dark current of the two-dimensional perovskite ultraviolet detector is two orders of magnitude lower than that of the three-dimensional perovskite detector. For detectors, reducing the dark current can effectively improve the detectivity of the device. Through testing, it is found that the detectivity of the two-dimensional perovskite ultraviolet detector is twice that of the three-dimensional perovskite ultraviolet detector (as Figure 6 ). The stability test of the two-dimensional and three-dimensional perovskite ultraviolet detectors prepared in this example is as Figure 7 shown. It can be seen that after 800 hours, the photocurrent of the two-dimensional RP-phase ultraviolet detector can maintain 67% of the initial value, while the photocurrent of the three-dimensional perovskite detector is only 20% of the initial value, indicating that the two-dimensional RP-phase perovskite material can significantly improve the stability of the device.

[0059] Example 2

[0060] Two-dimensional perovskite material (PEA)2(MA)2Pb3Cl 10 Photodetector device

[0061] Other steps are the same as those in Example 1, except that:

[0062] In step three, the A-site cation of the perovskite light absorption layer uses PEA +, The spin-coated perovskite active layer is (PEA)2(MA)2Pb3Cl 10 .

[0063] Example 3

[0064] Two-dimensional perovskite material (BA)2(FA)2Pb3Cl 10 Photodetector device

[0065] Other steps are the same as in Example 1, except that:

[0066] In Step 3, the A-site cation of the perovskite light absorption layer uses BA + , and the B-site cation uses FA + , and the spin-coated perovskite active layer is (BA)2(FA)2Pb3Cl 10 .

[0067] Example 4

[0068] Two-dimensional perovskite material (5AVA)2(FA)2Pb3Cl 10 Photodetector device

[0069] Other steps are the same as in Example 1, except that:

[0070] In Step 3, the A-site cation of the perovskite light absorption layer uses 5AVA + , and the B-site cation uses FA + , and the spin-coated perovskite active layer is (5AVA)2(FA)2Pb3Cl 10 .

[0071] Example 5

[0072] Two-dimensional perovskite material (3APA)2(FA)2Pb3Cl 10 Photodetector device

[0073] Other steps are the same as in Example 1, except that:

[0074] In Step 3, the A-site cation of the perovskite light absorption layer uses 3APA + , and the B-site cation uses FA + , and the spin-coated perovskite active layer is (3APA)2(FA)2Pb3Cl 10 .

[0075] Example 6

[0076] Two-dimensional perovskite material (PMA)2(Cs)2Pb3Cl 10 Photodetector device

[0077] Other steps are the same as in Example 1, except that:

[0078] In Step 3, the B-site cation of the perovskite light-absorbing layer uses Cs + , and the spin-coated perovskite active layer is (PMA)2(Cs)2Pb3Cl 10 .

[0079] Example 7

[0080] Two-dimensional perovskite material (PEA)2(Cs)2Pb3Cl 10 Photodetector device

[0081] Other steps are the same as those in Example 1, the difference is that:

[0082] In Step 3, the A-site cation of the perovskite light-absorbing layer uses PEA + , and the B-site cation uses Cs + , and the spin-coated perovskite active layer is (PEA)2(Cs)2Pb3Cl 10 .

[0083] Example 8

[0084] Two-dimensional perovskite material (BA)2(Cs)2Pb3Cl 10 Photodetector device

[0085] Other steps are the same as those in Example 1, the difference is that:

[0086] In Step 3, the A-site cation of the perovskite light-absorbing layer uses BA + , and the B-site cation uses Cs + , and the spin-coated perovskite active layer is (BA)2(Cs)2Pb3Cl 10 .

[0087] For the photodetector prepared above, the stability of the photodetector device prepared using the two-dimensional perovskite material will be greatly improved, the dark current of the device is significantly reduced, thereby significantly improving the detectivity of the device.

[0088] The present invention is not limited to the above embodiments, and can be changed within the scope of the claims. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

[0089] Matters not described in the present invention are well-known technologies.

Claims

1. A photodetector prepared from a two-dimensional perovskite material, characterized by The photodetector, from bottom to top, successively includes a transparent conductive glass substrate, a hole transport layer, a two-dimensional perovskite active layer, an electron transport layer, a hole blocking layer, an anti-corrosion metal layer, and a counter electrode metal; The perovskite active layer is a two-dimensional perovskite material with the general formula (A)2(B) n-1 Pb n Cl 3n+1 , and the A-site cation is PMA + (C6H5CH2NH3 + ), PEA + (C6H5(CH2)2NH3 + ), BA + (CH3(CH2)3NH3 + ), 5AVA + (HOOC(CH2)4NH3 + ), 3APA + (H00C(CH2)2NH3 + ), CH3CH2CH2NH3 + , CH(CH3)2CH2NH3 + , C(CH3)3NH3 + , CH3(CH2)4NH3 + , CH3(CH2) 11 NH3 + ); the B-site cation is MA + (CH3NH3 + ), FA + (NH2CH=NH2 + ), or Cs + ; The value of n is from 1 to 60; The substrate is preferably ITO conductive glass, and the resistance of ITO is 5 to 30 Ω; The counter electrode metal is gold, silver, copper, or aluminum; The anti-corrosion metal is bismuth or chromium; The thickness of the hole blocking layer is 1 - 50 nm, the thickness of the electron transport layer is 5 - 100 nm, the thickness of the perovskite active layer is 100 - 500 nm, the thickness of the hole transport layer is 5 - 100 nm, and the thickness of the anti-corrosion layer is 1 - 10 nm; The hole transport layer is at least one of 2,2',7,7'-tetrakis(diphenylamino)-9,9'-spirobifluorene (Spiro), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly-3-hexylthiophene (P3HT), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), molybdenum trioxide, nickel oxide, cuprous iodide, cuprous thiocyanate, copper phthalocyanine, chromium oxide; The electron transport layer is at least one of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), C60, zinc oxide nanoparticles, tin dioxide nanoparticles; The hole blocking layer is one of polyethyleneimine (PEI), Cr2O X , 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorene-2,7-diyl)-alt-[(9,9-dioctylfluorene-2,7-diyl)(PFN); The preparation method of the two-dimensional perovskite material for preparing a photodetector includes the following steps: (1) Pretreat the substrate: Ultrasonically clean the substrate with a glass cleaner, deionized water, and ethanol solution for 10 - 30 minutes respectively, then dry it in a nitrogen environment, and finally treat it in a UV-ozone machine for 15 - 30 minutes; (2) Fabricate the hole transport layer on the substrate: Put the cleaned substrate into the vacuum chamber. When the vacuum value is pumped down to below 6×10 -4 Pa, deposit the hole transport layer material onto the substrate by electron beam; (3) Prepare the perovskite light absorption layer: According to the molar ratio of A:B:Pb:Cl = 2:(n - 1):n:(3n + 1), add ACl, BCl, and PbCl2 into a solvent to obtain a perovskite precursor solution with a concentration of 0.2 - 1.5 mol / L; spin-coat the prepared perovskite precursor solution on the hole transport layer, then obtain a 100 - 400 nm thin film through low-pressure assisted treatment, and then perform annealing treatment; the concentration of the precursor solution is calculated based on the content of Pb; (4) Prepare the electron transport layer: Spin-coat the electron transport layer solution on the surface of the perovskite thin film, and obtain the electron transport layer by controlling the rotation speed of the spin coater (1000 - 3000 rpm); the thickness is 30 - 50 nm; The concentration of the electron transport layer solution is 10 - 40 mg / mL; (5) Prepare the hole blocking layer: Spin-coat the hole blocking layer solution on the surface of the electron transport layer, and obtain the hole blocking layer by controlling the rotation speed of the spin coater (2000 - 6000 rpm); the thickness is 20 - 50 nm; The concentration of the hole blocking layer solution is 0.2 - 1.5 mg / mL; (6) Prepare the metal counter electrode: Put the device obtained in step (5) into a high-resistance vacuum coating instrument. After the chamber vacuum reaches 10 -4 -10 -5 Pa, heat the electrode. First deposit the anti-corrosion metal, and then continuously deposit the metal counter electrode on the anti-corrosion metal to complete the preparation of the entire photodetector, and finally obtain a photodetector prepared from a two-dimensional perovskite material.

2. The photodetector prepared from the two-dimensional perovskite material according to claim 1, characterized in that, In the preparation method, the ACl described in step (3) is C6H5CH2NH3Cl, C6H5(CH2)2NH3Cl), CH3(CH2)3NH3Cl), HOOC(CH2)4NH3Cl), H00C(CH2)2NH3Cl, CH3CH2CH2NH3Cl, CH(CH3)2CH2NH3Cl, C(CH3)3NH3Cl, CH3(CH2)4NH3Cl or CH3(CH2) 11 NH3Cl; The BCl is CH3NH3Cl, NH2CH = NH2Cl, or CsCl; The solvent described above is one or more of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc).

3. The photodetector prepared from the two-dimensional perovskite material according to claim 1, characterized in that, In the preparation method, the two-dimensional perovskite film in step (3) is prepared by a low-pressure assisted method, and the pressure is 1 - 500 Pa; The rotation speed is 3000 - 6000 rpm, the annealing temperature is 70 - 110 °C, and the annealing time is 5 - 20 min.

4. The photodetector prepared from the two-dimensional perovskite material according to claim 1, characterized in that, In the preparation method, the evaporation rate of the deposition in step (6) is 0.03 - 0.08 nm / s.

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