Perovskite and organic heterojunction composite near-infrared photodetector and preparation method

Abstract

The application belongs to the technical field of near-infrared fast-response photoelectric detectors, and particularly relates to a perovskite and organic heterojunction composite near-infrared photoelectric detector capable of realizing near-infrared fast response and a preparation method thereof. 16 The material of the two-dimensional perovskite active layer is two-dimensional perovskite (PEA)2(MA)4Pb5I 16 The material of the organic heterojunction active layer (5) is PTB7-Th:Y6, and the material of the interface modification layer is Al2O3. The application can realize wide-spectrum response in a wavelength interval of 375 nm-1550 nm, and the final rising edge time is 30 ns and the falling edge time is 621 ns, thereby providing a new technical approach for developing low-cost near-infrared fast-response photoelectric detectors.

Description

Technical Field

[0001] This invention belongs to the field of near-infrared fast-response photodetector technology, specifically a near-infrared photodetector composed of perovskite and organic heterojunction that can achieve near-infrared fast response and its preparation method. Background Technology

[0002] A photodetector is a device that converts light signals into electrical signals using the photoelectric effect. Organic semiconductor materials have attracted widespread attention due to their abundance, low cost, and good flexibility; however, their low mobility typically limits the response speed of these devices. Perovskite materials, with their excellent optical and electrical properties, especially their high carrier mobility, are candidate materials for next-generation fast-response photodetectors. However, the response range of existing perovskite photodetectors is limited to the visible wavelength range. Therefore, to achieve fast photodetection in the near-infrared region, improvements to the structure and fabrication methods of existing photodetectors are necessary. Summary of the Invention

[0003] This invention overcomes the shortcomings of existing technologies and addresses the technical problems of slow response speed of organic photodetectors and limited response range of perovskite photodetectors.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a near-infrared photodetector composed of perovskite and heterojunction, comprising, sequentially arranged, an anode layer, a hole transport layer, an interface modification layer, a two-dimensional perovskite active layer, an organic heterojunction active layer, a hole blocking layer, and a cathode layer, wherein the material of the two-dimensional perovskite active layer is two-dimensional perovskite (PEA)2(MA)4Pb5I. 16 The material of the active layer of the organic heterojunction is PTB7-Th:Y6.

[0005] The material of the interface modification layer is Al2O3, and the thickness of the interface modification layer is 1-2 nm.

[0006] The thickness of the interface modification layer is 1.4 nm.

[0007] The anode layer is made of ITO, the hole transport layer is made of PTAA, the hole blocking layer is made of BCP, and the cathode layer is made of silver.

[0008] The thickness of the two-dimensional perovskite active layer is 250–300 nm, and the thickness of the organic heterojunction active layer is 130–150 nm.

[0009] The thickness of the two-dimensional perovskite active layer is 280±10nm, the thickness of the organic heterojunction active layer is 140nm, the thickness of the anode layer is 150±20nm, the thickness of the hole transport layer is 30±2nm, the thickness of the hole blocking layer is 45±5nm, and the thickness of the cathode layer is 100±10nm.

[0010] The material of the active layer of the organic heterojunction is: PTB7-Th:Y6 (1:1.5, wt:wt).

[0011] Furthermore, the present invention also provides a method for fabricating a near-infrared photodetector composed of perovskite and heterojunction, comprising the following steps:

[0012] Step 1: Prepare a hole transport layer on the surface of the anode layer by spin coating;

[0013] Step 2: Prepare an interface modification layer by depositing Al2O3 on the hole transport layer using an atomic layer deposition device;

[0014] Step 3: Preparation of the two-dimensional perovskite active layer: A two-dimensional perovskite (PEA)2(MA)4Pb5I was prepared with the following molar ratios: PEA:MAI:PbI2:NH4SCN:NH4Cl = 2:4:5:1:1, and DMF as the solvent. 16 The solution was then spin-coated onto the Al2O3 interface modification layer using a two-dimensional perovskite (PEA)2(MA)4Pb5I solution. 16 Solution preparation for two-dimensional perovskite active layer;

[0015] Step 4: Dissolve the donor material PTB7-Th and the acceptor material Y6 in chlorobenzene at a mass ratio of 1:1.5 to obtain a PTB7-Th:Y6 solution. Spin-coat the PTB7-Th:Y6 solution onto the surface of the two-dimensional perovskite active layer to obtain the organic heterojunction active layer.

[0016] Step 5: Prepare a hole blocking layer on the surface of the active layer of the organic heterojunction by spin coating, and prepare a cathode layer on the hole blocking layer by vacuum evaporation equipment.

[0017] In step three, the two-dimensional perovskite (PEA)2(MA)4Pb5I... 16 The solution concentration is 1M, and in step four, the concentration of the PTB7-Th:Y6 solution is 20mg / mL.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This invention selects a two-dimensional perovskite (PEA)2(MA)4Pb5I with high carrier mobility and stronger stability. 16A two-dimensional perovskite active layer is formed, and then an organic heterojunction active layer is constructed using PTB7-Th, a donor material with a low HOMO energy level, and Y6, an acceptor material with strong near-infrared light absorption characteristics. The organic heterojunction active layer and the two-dimensional perovskite active layer are combined as the active layer of a photodetector, which can realize rapid photodetection in the near-infrared spectral range.

[0020] 2. In this application, Al2O3 at the nm level is added as an interface modification layer between the hole transport layer PTAA and the two-dimensional perovskite to form a structure of ITO / PTAA / Al2O3 / (PEA)2(MA)4Pb5I 16 The / PTB7-Th:Y6 / BCP / Ag photodetector not only achieved a broad-spectrum response in the 375nm-1550nm wavelength range, but experiments also confirmed that, under a 1.4nm thick interface modification layer, the device, with a -2V reverse bias and 850nm near-infrared light (optical power density: 5.09mW / cm²), exhibited excellent performance. 2 The ratio of bright to dark current density during irradiation can reach as high as 10. 5 . Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the near-infrared fast-response photodetector provided in Embodiment 1 of the present invention. In the figure: 1-anode layer, 2-hole transport layer, 3-interface modification layer, 4-two-dimensional perovskite active layer, 5-organic heterojunction active layer, 6-hole blocking layer, 7-cathode layer.

[0022] Figure 2 The dark current density-voltage characteristic curves of the near-infrared fast-response photodetector and the device without an alumina interface modification layer are shown in the embodiments of the present invention.

[0023] Figure 3 The optical absorption spectra of PTB7-Th thin films, Y6 thin films, and PTB7-Th:Y6 (1:1.5, wt:wt) thin films are shown.

[0024] Figure 4 The dark current density-voltage characteristic curve of the near-infrared responsive fast photodetector of the present invention, and the photocurrent density-voltage characteristic curve in the 375-1550nm band (optical power density: 5.09mW / cm2);

[0025] Figure 5 The transient photocurrent response curve of the near-infrared responsive fast organic photodetector of the present invention under pulsed light source illumination of 375-1550nm (optical power density: 5.09mW / cm2);

[0026] Figure 6The transient photocurrent response curve of the standard device of the present invention without the alumina interface modification layer under a 1310nm light source is shown.

[0027] Figure 7 The transient photocurrent curve of the near-infrared fast-response photodetector in this embodiment of the invention is shown under illumination by an 850nm femtosecond pulse light source. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] like Figure 1 As shown, Embodiment 1 of the present invention provides a near-infrared photodetector composed of perovskite and heterojunction, comprising, in sequence, an anode layer 1, a hole transport layer 2, an interface modification layer 3, a two-dimensional perovskite active layer 4, an organic heterojunction active layer 5, a hole blocking layer 6, and a cathode layer 7. The material of the two-dimensional perovskite active layer 4 is two-dimensional perovskite (PEA)2(MA)4Pb5I. 16 The material of the organic heterojunction active layer 5 is PTB7-Th:Y6, and the material of the interface modification layer is Al2O3.

[0031] Specifically, in this embodiment, the thickness of the interface modification layer 3 is 1-2 nm.

[0032] Preferably, in this embodiment, the thickness of the interface modification layer 3 is 1.4 nm.

[0033] Specifically, in this embodiment, the anode layer 1 is made of indium tin oxide (ITO), the hole transport layer 2 is made of PTAA, the hole blocking layer 6 is made of BCP, and the cathode layer 7 is made of silver.

[0034] Specifically, in this embodiment, the thickness of the two-dimensional perovskite active layer 4 is 250-300 nm, and the thickness of the organic heterojunction active layer 5 is 130-150 nm.

[0035] Preferably, in this embodiment, the thickness of the two-dimensional perovskite active layer 4 is 280±10nm, and the thickness of the organic heterojunction active layer 5 is 140nm.

[0036] Specifically, in this embodiment, the thickness of the anode layer 1 is 150±20nm, the thickness of the hole transport layer 2 is 30±2nm, the thickness of the hole blocking layer 6 is 45±5nm, and the thickness of the cathode layer 7 is 100±10nm.

[0037] Preferably, in this embodiment, the material of the organic heterojunction active layer 5 is: PTB7-Th:Y6 (1:1.5, wt:wt), that is, the mass ratio of PTB7-Th to Y6 is 1:1.5.

[0038] Example 2

[0039] Embodiment 2 of this invention provides a method for fabricating a near-infrared photodetector composed of perovskite and heterojunction as described in Embodiment 1. Taking an anode layer 1 made of indium tin oxide (ITO), a hole transport layer 2 made of PTAA, a hole blocking layer 6 made of BCP, and a cathode layer 7 made of silver as an example, the structure of the photodetector is: ITO / PTAA / Al₂O₃ / (PEA)₂(MA)₄Pb₅I₂ 16 The specific preparation method of this embodiment will be illustrated by using / PTB7-Th:Y6 / BCP / Ag.

[0040] The materials used in this embodiment include: ITO glass, deionized water, anhydrous ethanol, isopropanol, PTAA, toluene, lead iodide, methyl ammonium iodide (CH3NH3I), phenylethyl ammonium iodide (PEAI), ammonium thiocyanate (NH4SCN), ammonium chloride (NH4Cl), N,N-dimethylformamide solution (DMF), PTB7-Th, Y6, chlorobenzene, and BCP. Their amounts are as follows:

[0041] Deionized water: 100mL ± 5mL;

[0042] Isopropanol: 100mL ± 5mL;

[0043] Anhydrous ethanol: 100mL ± 5mL;

[0044] PTAA: 0.01g;

[0045] Toluene: 1 mL;

[0046] Lead iodide: 0.461g ± 0.001g;

[0047] Methylammonium iodide (CH3NH3I): 0.1272 g ± 0.001 g;

[0048] Phenylethyl ammonium iodide (PEAI): 0.0996 g ± 0.001 g;

[0049] Ammonium thiocyanate (NH4SCN): 0.0152 g ± 0.001 g;

[0050] Ammonium chloride (NH4Cl): 0.0106 g ± 0.001 g;

[0051] Solution N,N-dimethylformamide (DMF): 1 mL;

[0052] PTB7-Th: 0.008g;

[0053] Y6: 0.012g;

[0054] Chlorobenzene: 1 mL;

[0055] BCP: 0.005g.

[0056] Before preparation, the chemical materials required for the preparation need to be carefully selected, and their quality, purity, concentration, fineness, and precision need to be controlled, as follows:

[0057] Deionized water: a liquid with a purity of 99.99%;

[0058] Isopropanol: Liquid, purity 99.5%;

[0059] Anhydrous ethanol: a liquid, analytical grade;

[0060] PTAA: Solid powder, 99% purity;

[0061] Toluene: a liquid with a purity of 99%;

[0062] Lead iodide: solid powder, purity 99.9%;

[0063] Methylammonium iodide (CH3NH3I): solid powder, purity 99.5%;

[0064] Phenylethyl ammonium iodide (PEAI): solid powder, 99% purity;

[0065] Ammonium thiocyanate (NH4SCN): solid powder, purity 99%;

[0066] Ammonium chloride (NH4Cl): solid powder, purity 98%;

[0067] PTB7-Th: Fine fibers, dark brown;

[0068] Y6: Solid powder, with a particle size ≤28 micrometers and a purity of 99.99%;

[0069] Chlorobenzene: a liquid with a purity of 99%;

[0070] BCP: Solid powder, 98% purity;

[0071] Conductive glass (indium tin oxide, ITO): solid, transmittance approximately 86%, surface roughness Ra: 0.16-0.32 nm, sheet resistance 10 Ω / cm 2 .

[0072] Specifically, the fabrication method of a near-infrared photodetector composed of perovskite and heterojunction as described in this embodiment includes the following steps:

[0073] Step 1: Prepare hole transport layer 2 on the surface of anode layer 1 by spin coating.

[0074] In this embodiment, the anode layer 1 is made of ITO glass, and its substrate treatment method is as follows:

[0075] 1) Place the ITO glass in a mixture of detergent and scouring powder and sonicate for 15 minutes;

[0076] 2) Place the ultrasonically cleaned ITO glass in a cleaning container and manually rub it repeatedly on both sides until a water film forms;

[0077] 3) The cleaned ITO glass was ultrasonically treated in deionized water, anhydrous ethanol, and isopropanol, respectively, for 15 minutes in each solvent. After removal, it was dried with nitrogen gas.

[0078] In this embodiment, the hole transport layer 2 is prepared by dissolving PTAA in toluene to prepare a solution with a concentration of 10 mg / mL. 25 μL of the PTAA solution is spin-coated onto the prepared ITO substrate at 4000 rpm for 40 s, and then annealed on a hot plate at 100°C for 10 min, resulting in a final thickness of 30 nm.

[0079] Step 2: Using atomic layer deposition equipment, Al2O3 is deposited on hole transport layer 2 to obtain interface modification layer 3. The specific method is as follows:

[0080] 1) Install the raw materials trimethylaluminum (Al(CH3)3) and water (H2O) in the ALD deposition system in advance, and set the reactor temperature to 150℃, the inlet pipe temperature to 150℃, and the exhaust pipe temperature to 85℃.

[0081] 2) The ITO conductive glass substrate is placed into the ALD glove box and deposited with Al2O3 with a thickness of 1.4 nm at a rate of 0.05 nm / cycle by alternating reactions of Al(CH3)3 and H2O under a vacuum environment of 150°C. After the reaction is completed, it is cooled for 5 min and then ready for use.

[0082] Step 3: Preparation of the two-dimensional perovskite active layer: A two-dimensional perovskite (PEA)2(MA)4Pb5I was prepared with the following molar ratios: PEA:MAI:PbI2:NH4SCN:NH4Cl = 2:4:5:1:1, and DMF as the solvent. 16 The solution was then spin-coated onto the Al2O3 interface modification layer using a two-dimensional perovskite (PEA)2(MA)4Pb5I solution. 16 A solution was used to prepare a two-dimensional perovskite active layer.

[0083] In step three, the two-dimensional perovskite (PEA)2(MA)4Pb5I... 16 The solution concentration was 1M. The specific spin coating method was as follows: 60μL of perovskite solution was spread on the substrate in a glove box, and spin coating was performed at a speed of 5000rpm for 45s. Then, the substrate was placed on a hot plate at 100℃ for annealing for 15min. The final active layer thickness was 280nm.

[0084] Step 4: Dissolve the donor material PTB7-Th and the acceptor material Y6 in chlorobenzene at a mass ratio of 1:1.5 to obtain a PTB7-Th:Y6 solution. Spin-coat the PTB7-Th:Y6 solution onto the surface of the two-dimensional perovskite active layer to obtain the organic heterojunction active layer 5.

[0085] In step four, the concentration of the PTB7-Th:Y6 solution is 20 mg / mL. The specific spin-coating method is as follows: 40 μL of PTB7-Th:Y6 solution is spin-coated at 700 rpm for 40 s, and then placed on a 100℃ hot plate for annealing for 2 min. The final active layer thickness is 140 nm.

[0086] Step 5: Prepare a hole blocking layer 6 on the surface of the organic heterojunction active layer 5 by spin coating, and prepare a cathode layer 7 on the hole blocking layer 6 by vacuum evaporation equipment.

[0087] The hole-blocking layer 6 was prepared as follows: BCP was dissolved in isopropanol at a concentration of 0.5 mg / mL. 25 μL of the BCP solution was spin-coated onto the PCBM film surface at 6000 rpm for 40 s. The final BCP layer thickness was 45 nm.

[0088] The method for preparing cathode layer 7 (Ag electrode) is as follows:

[0089] 1) Turn on the vacuum evaporation equipment, check if the instrument is working properly, and turn on the circulating water switch;

[0090] 2) Place the prepared glass substrate on a special mask, making sure that the bottom ITO electrode and the mask electrode are placed crosswise, with the ITO side facing down. Then fix the mask on the turntable inside the evaporation chamber.

[0091] 3) Place the silver particles on the tantalum boat at the bottom of the vapor deposition chamber;

[0092] 4) Close the chamber door, start the vacuum evaporation equipment with one button, and wait for the vacuum degree inside the evaporation chamber to be less than 5×10. -4 Pa;

[0093] 5) Turn on the turntable to rotate the glass substrate and ensure uniform film deposition;

[0094] 6) Turn on the power supply of the tantalum boat containing silver, turn on the quartz crystal oscillator probe to detect the deposition rate. When the rate is 1nm / s, turn on the large baffle to start the evaporation process.

[0095] 7) Use a film thickness gauge to measure the required thickness; the thickness of silver is 100 nm.

[0096] 8) After the evaporation is completed, take out the sample and perform a rough extraction of the evaporation chamber according to the operation. Then turn off the instrument power and circulating water switches in sequence.

[0097] Detection, analysis, and characterization

[0098] The performance of the near-infrared fast-response photodetector prepared in this embodiment was tested and characterized. All device tests were performed in a dark chamber to shield against interference from other signals. The absorption spectrum of the device was measured using a UV-Vis-NIR spectrophotometer. The current density-voltage curves of the device under dark conditions and at light sources of 375nm, 532nm, 850nm, 980nm, 1120nm, 1310nm, and 1550nm were characterized using a Keithley 2400 digital source meter. The transient photocurrent response curves under light sources of 375nm, 532nm, 850nm, 980nm, 1120nm, 1310nm, and 1550nm were characterized using an Agilent B2902A. The influence of the presence or absence of an Al2O3 interface modification layer on the device performance was compared. The response speed of the device under an 850nm femtosecond laser light source was characterized using a femtosecond laser and an oscilloscope. The specific conclusions are as follows.

[0099] Figure 2 The dark current density-voltage characteristic curves of the near-infrared fast-response photodetector of the present invention with and without the alumina interface modification layer are given. Figure 2 This demonstrates that by inserting an Al2O3 interface modification layer between the hole transport layer and the two-dimensional perovskite, the crystallinity of the two-dimensional perovskite film is improved, pinhole defects are eliminated, and internal nonradiative recombination is reduced, thereby lowering the dark current of the device.

[0100] Figure 3 Characterized (PEA)2(MA)4Pb5I 16The optical absorption spectra of two-dimensional perovskite films, PTB7-Th:Y6 (1:1.5, wt:wt) organic heterojunction films, and composite films were studied. The two-dimensional perovskite exhibits strong absorption in the visible light band, but weak absorption in the near-infrared band. The active layer formed by combining it with a PTB7-Th:Y6 bulk heterojunction can enhance the absorption intensity in the near-infrared region.

[0101] Figure 4 The figures show the dark current density-voltage characteristic curves of the photodetector obtained in this embodiment of the invention, as well as the current density-voltage curves under light sources of 375nm, 532nm, 850nm, 980nm, 1120nm, 1310nm, and 1550nm. As can be seen from the figures, the device obtained by this invention has a very low dark current density, reaching 10 at -1V. -4 mA / cm 2 The photocurrent density of the device is greater than its dark current density under illumination at 375nm, 532nm, 850nm, 980nm, 1120nm, 1310nm and 1550nm light sources, with the highest photocurrent density under 532nm light illumination.

[0102] Figure 5 The transient photocurrent response curves of the photodetector obtained in the embodiments of the present invention under light sources of 375nm, 532nm, 850nm, 980nm, 1120nm, 1310nm and 1550nm; Figure 5 The photodetector obtained in the embodiments of the present invention exhibits a significant step response under illumination from light sources at 375nm, 532nm, 850nm, 980nm, 1120nm, 1310nm and 1550nm.

[0103] Figure 6 The control device without an alumina interface modification layer (structure: ITO / PTAA / (PEA)2(MA)4Pb5I) 16 The transient photocurrent response curve of / PTB7-Th:Y6 / BCP / Ag) under a 1310nm light source shows that the control device without an alumina interface modification layer no longer has a step response under a 1310nm light source.

[0104] Figure 7 The transient photocurrent response of the photodetector obtained in this embodiment of the invention under an 850nm femtosecond laser source is presented. Figure 7 It can be seen that the device has a fast response speed. The calculation shows that the rise time of the transient optical circuit of the device is 30ns and the fall time is 621ns.

[0105] In summary, this invention combines perovskite with an organic heterojunction to provide a near-infrared photodetector that combines perovskite and a heterojunction. This solves the two problems of slow response speed in existing organic photodetectors and limited response range in perovskite photodetectors. It also addresses the limitations of standard devices such as ITO / PTAA / (PEA)2(MA)4Pb5I. 16 A 1.4 nm thick Al₂O₃ layer was introduced as an interface modification layer between the hole transport layer PTAA of / PTB7-Th:Y₆ / BCP / Ag and the two-dimensional perovskite. The resulting detector achieved a broad-spectrum response in the wavelength range of 375 nm to 1550 nm, with a rise time of 30 ns and a fall time of 621 ns. This invention provides a new technical approach for developing low-cost, fast-response near-infrared photodetectors.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A near-infrared photodetector composed of perovskite and heterojunction, characterized in that: The structure includes, in sequence, an anode layer (1), a hole transport layer (2), an interface modification layer (3), a two-dimensional perovskite active layer (4), an organic heterojunction active layer (5), a hole blocking layer (6), and a cathode layer (7). The material of the two-dimensional perovskite active layer (4) is two-dimensional perovskite (PEA)2(MA)4Pb5I. 16 The material of the organic heterojunction active layer (5) is PTB7-Th:Y6, and the material of the interface modification layer is Al2O3.

2. The near-infrared photodetector composed of perovskite and heterojunction according to claim 1, characterized in that: The thickness of the interface modification layer (3) is 1~2nm.

3. A near-infrared photodetector composed of perovskite and heterojunction according to claim 2, characterized in that: The thickness of the interface modification layer (3) is 1.4 nm.

4. A near-infrared photodetector composed of perovskite and heterojunction according to claim 1, characterized in that, The anode layer (1) is made of ITO, the hole transport layer (2) is made of PTAA, the hole blocking layer (6) is made of BCP, and the cathode layer (7) is made of silver.

5. A near-infrared photodetector composed of perovskite and heterojunction according to claim 1, characterized in that, The thickness of the two-dimensional perovskite active layer (4) is 250~300nm, and the thickness of the organic heterojunction active layer (5) is 130~150nm.

6. A near-infrared photodetector composed of perovskite and heterojunction according to claim 1, characterized in that, The thickness of the two-dimensional perovskite active layer (4) is 280±10 nm, the thickness of the organic heterojunction active layer (5) is 140 nm, the thickness of the anode layer (1) is 150±20 nm, the thickness of the hole transport layer (2) is 30±2 nm, the thickness of the hole blocking layer (6) is 45±5 nm, and the thickness of the cathode layer (7) is 100±10 nm.

7. A near-infrared photodetector composed of perovskite and heterojunction according to claim 1, characterized in that, The material of the organic heterojunction active layer (5) is PTB7-Th:Y6 with a mass ratio of 1:1.

5.

8. A method for fabricating a near-infrared photodetector composed of perovskite and heterojunction according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Prepare a hole transport layer (2) on the surface of the anode layer (1) by spin coating. Step 2: Using an atomic layer deposition device, Al2O3 is deposited on the hole transport layer (2) to obtain an interface modification layer (3); Step 3: Preparation of the two-dimensional perovskite active layer: A two-dimensional perovskite (PEA)2(MA)4Pb5I was prepared with the following molar ratios: PEA:MAI:PbI2:NH4SCN:NH4Cl = 2:4:5:1:1, and DMF as the solvent. 16 The solution was then spin-coated onto the Al2O3 interface modification layer using a two-dimensional perovskite (PEA)2(MA)4Pb5I solution. 16 Solution preparation for two-dimensional perovskite active layer; Step 4: Dissolve the donor material PTB7-Th and the acceptor material Y6 in chlorobenzene at a mass ratio of 1:1.5 to obtain a PTB7-Th:Y6 solution. Spin-coat the PTB7-Th:Y6 solution onto the surface of the two-dimensional perovskite active layer to obtain the organic heterojunction active layer (5). Step 5: Prepare a hole blocking layer (6) on the surface of the organic heterojunction active layer (5) by spin coating, and prepare a cathode layer (7) on the hole blocking layer (6) by vacuum evaporation equipment.

9. A method for fabricating a near-infrared photodetector composed of perovskite and heterojunction according to any one of claims 8, characterized in that, In step three, the two-dimensional perovskite (PEA)2(MA)4Pb5I... 16 The solution concentration is 1 M, and in step four, the concentration of the PTB7-Th:Y6 solution is 20 mg / mL.

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