Heterojunction-based position sensitive detector and preparation method and application thereof

Abstract

The invention discloses a heterojunction-based position sensitive detector and a preparation method and application thereof, and the position sensitive detector comprises a silicon substrate layer, an MAPbI3: P (VDF-TrFE) composite film light absorption layer and a transparent conductive layer which are sequentially arranged from bottom to top. A first electrode and a second electrode are arranged on the end face, away from the MAPbI3: P (VDF-TrFE) composite film light absorption layer, of the transparent conducting layer at intervals. Wherein the silicon substrate layer and the MAPbI3: P (VDF-TrFE) composite thin film light absorption layer form an MAPbI3: P (VDF-TrFE) / Si heterojunction.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric detectors, and in particular to a position sensitive detector based on a heterojunction, a preparation method and applications thereof. Background Art

[0002] Under the irradiation of non-uniform light (i.e., point light source), the pn junction, heterojunction, or metal semiconductor junction forms a concentration gradient due to the difference in carrier concentration between the illuminated area and the non-illuminated area, thereby generating a voltage between the two electrodes on the same side. This phenomenon is called the lateral photovoltaic effect. When the point light source moves between the two electrodes, the generated photovoltage shows a linear relationship with the irradiation position. Due to this characteristic, the lateral photovoltaic effect is widely used in position-sensitive detectors, which can accurately detect changes in the illumination position.

[0003] Position sensitive detectors based on the lateral photovoltaic effect principle have shown broad application prospects in various fields due to their advantages such as high sensitivity, rapid response, non-contact measurement capability and no need for external power supply. However, traditional single-function position detection technology has been unable to meet the diverse and high-precision requirements of complex applications. Therefore, improving the performance of position sensitive detectors and their ability to process composite information has become an urgent problem to be solved. Summary of the invention

[0004] In response to the problems and needs raised above, this solution proposes a position-sensitive detector based on a heterojunction, a preparation method and its application. By adopting the following technical features, the above-mentioned technical objectives can be achieved and many other technical effects can be brought about.

[0005] One object of the present invention is to provide a position sensitive detector based on a heterojunction, comprising a silicon substrate layer, a MAPbI 3 :P(VDF-TrFE) composite film light absorbing layer and transparent conductive layer, wherein the transparent conductive layer deviates from MAPbI 3 : A first electrode and a second electrode are arranged at intervals on the end surface of the P(VDF-TrFE) composite thin film light absorbing layer;

[0006] Wherein, the silicon substrate layer and the MAPbI 3 MAPbI:P(VDF-TrFE) composite film light absorption layer forms 3 :P(VDF-TrFE) / Si heterojunction.

[0007] In addition, the heterojunction-based position sensitive detector and preparation method according to the present invention may also have the following technical features:

[0008] In one example of the present invention, the MAPbI 3:The thickness of the P(VDF-TrFE) composite film absorption layer is 80-1100nm.

[0009] In one example of the present invention, the transparent conductive layer is an ITO conductive layer, and its thickness is 10-30 nm.

[0010] In an example of the present invention, the first electrode and the second electrode are silver electrodes, both of which have a square cross-section with a side length not exceeding 1 mm, and the spacing between the first electrode and the second electrode is 0.4-1 mm.

[0011] Another object of the present invention is to provide a method for preparing a position sensitive detector based on a heterojunction as described above, comprising the following steps:

[0012] S10: ultrasonically clean the silicon substrate with acetone, ethanol and deionized water in sequence, and dry it for later use;

[0013] S20: Place the silicon substrate in a mixed solution of hydrofluoric acid and water to remove the surface SiO 2 layer;

[0014] S30: Add the perovskite precursor solution to the surface of the silicon substrate to form MAPbI 3 : The P(VDF-TrFE) composite thin film light-absorbing layer is annealed on a heating table after being allowed to stand at room temperature;

[0015] S40: MAPbI 3 : The P(VDF-TrFE) composite thin film light-absorbing layer is placed in a magnetron sputtering chamber and evacuated, and then argon gas is introduced to maintain the pressure in the chamber at a first specified pressure, and a transparent conductive layer is magnetron sputtered using ITO as a target;

[0016] S50: placing the transparent conductive layer in a magnetron sputtering chamber and evacuating the chamber, then introducing argon gas to maintain the pressure in the chamber at a second specified pressure, and performing magnetron sputtering with a metal as a target to form a first electrode and a second electrode.

[0017] In one example of the present invention, in step S30, the preparation of the perovskite precursor solution includes the following steps:

[0018] S31: dissolving a certain amount of P(VDF-TrFE) in N,N-dimethylformamide solution;

[0019] S32: PbI 2 With CH 3 NH 3 I is added to the above P(VDF-TrFE) solution at a specified molar ratio to form a perovskite precursor solution.

[0020] In one example of the present invention, in step S32, PbI 2 With CH 3 NH 3 I is added to the P(VDF-TrFE) solution at a molar ratio of 1:1 to form a perovskite precursor solution, and the prepared perovskite precursor solution is magnetically stirred at room temperature to make the concentration of P(VDF-TrFE) reach 0-1wt%.

[0021] In one example of the present invention, in step S50, the perovskite precursor solution is dropped onto the surface of the substrate by spin coating to form MAPbI 3 :P(VDF-TrFE) composite thin film light absorbing layer, after spin coating, let it stand at room temperature, and then put it on a heating table preheated to 80-90℃ for annealing for 5-7h.

[0022] Another object of the present invention is to propose an application of a position sensitive detector based on a heterojunction prepared by the above-mentioned preparation method, wherein the position sensitive detector is applied to wavelength-resolved demodulation.

[0023] Another object of the present invention is to propose an application of a position sensitive detector based on a heterojunction prepared by the preparation method as described above, wherein the position sensitive detector is applied to multi-dimensional optical information detection.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention is based on perovskite MAPbI 3 The addition of polymer P(VDF-TrFE) to the MAPbI nanostructured film improves the photoresponse of the device by regulating the surface resistance of the position-sensitive detector. When the concentration of P(VDF-TrFE) is 0.2wt%, the photoresponse of the device is significantly improved compared with that of the undoped MAPbI nanostructured film. 3 The response signal of the thin film layer increased by more than 1.6 times, obtaining a higher signal and more sensitive detection.

[0026] 2. Composite perovskite film MAPbI in the present invention 3 :P(VDF-TrFE) combines with Si to form a pn junction, which expands the detection range to 405nm-1064nm.

[0027] 3. The introduction of pyroelectric polymer P(VDF-TrFE) makes the instantaneous photovoltage (LPV) of the position sensitive detector after the pyroelectric field is introduced. photo+pyro ) compared to the transient stable photovoltage (LPV) generated by the lateral photovoltaic effect photo ) value increased by more than 1.4 times, resulting in a higher signal and better response.

[0028] 4. The nonlinearity of the present invention is controlled within 8.5%, the highest position sensitivity reaches 688.10 mV / mm, and the measurable wavelength range is 405-1064 nm.

[0029] 5. The present invention combines the binary coding of the laser irradiation position with the lateral photovoltage response at a specific wavelength to achieve wavelength-resolved photoelectric demodulation in the visible-near infrared range (405-1064nm).

[0030] 6. MAPbI in the present invention 3 :The P(VDF-TrFE) / Si heterojunction position-sensitive detector exhibits excellent photoelectric response characteristics under different wavelengths, irradiation positions and laser intensities, and can also effectively detect multi-dimensional optical information of wavelength, position and light intensity through the photovoltage enhancement ratio generated by the pyroelectric effect.

[0031] The best embodiment for carrying out the present invention will be described in more detail below with reference to the accompanying drawings so that the features and advantages of the present invention can be easily understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention, wherein the drawings are only used to illustrate some embodiments of the present invention, but not to limit all embodiments of the present invention thereto.

[0033] Figure 1 An experimental schematic diagram of a position sensitive detector based on a heterojunction according to one embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of an experiment of a position sensitive detector based on a heterojunction according to another embodiment of the present invention;

[0035] Figure 3 for Figure 1 The lateral photovoltage of the position-sensitive detector obtained from the experimental setup varies with the P(VDF-TrFE) doping concentration.

[0036] Figure 4 for Figure 1 A graph showing how the lateral photovoltage of the position-sensitive detector obtained from the experimental setup changes with the wavelength of the irradiated laser.

[0037] Figure 5 for Figure 2 The transient stable photovoltage of the position sensitive detector obtained by the experimental device and the instantaneous photovoltage after the introduction of the pyroelectric field vary with laser power.

[0038] Figure 6 for Figure 2The position-sensitive detector obtained from the experimental setup is based on the "HBU" decoding of the lateral photovoltage generated at different wavelengths and positions.

[0039] Figure 7 for Figure 2 Schematic diagram of different irradiation positions of the position-sensitive detector obtained from the experimental setup in multi-dimensional optical information detection.

[0040] Figure 8 for Figure 2 The lateral photovoltage enhancement ratio generated by the position-sensitive detector obtained from the experimental device under different wavelengths, light intensities and irradiation positions.

[0041] List of reference numerals:

[0042] Silicon substrate layer 1;

[0043] MAPbI 3 :P(VDF-TrFE) composite film light absorbing layer 2;

[0044] Transparent conductive layer 3;

[0045] A first electrode 4;

[0046] A second electrode 5;

[0047] Voltmeter 6;

[0048] Laser 7;

[0049] Chopper 8;

[0050] Oscilloscope 9. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the technical solution of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the drawings of specific embodiments of the present invention. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not necessarily indicate a quantity limitation. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0053] According to the first aspect of the present invention, a position sensitive detector based on a heterojunction comprises a silicon substrate layer 1, a MAPbI 3 :P(VDF-TrFE) composite film light absorbing layer 2 and transparent conductive layer 3, wherein the transparent conductive layer 3 deviates from MAPbI 3 : A first electrode 4 and a second electrode 5 are arranged at intervals on the end surface of the P (VDF-TrFE) composite thin film light absorbing layer 2;

[0054] Wherein, the silicon substrate layer 1 and the MAPbI 3 :P(VDF-TrFE) composite film light absorption layer 2 forms MAPbI 3 :P(VDF-TrFE) / Si heterojunction.

[0055] This position-sensitive detector is based on the perovskite MAPbI 3 The addition of polymer P(VDF-TrFE) to the device improves the photoresponse of the device by regulating the surface resistance of the position-sensitive detector. Compared with the undoped MAPbI 3 The response signal of the film layer is greatly improved, a higher signal is obtained, and the detection is more sensitive; the composite perovskite film MAPbI in the position sensitive detector 3 :P(VDF-TrFE) combines with Si to form a pn junction, which expands the detection range to 405nm-1064nm. The introduction of the pyroelectric polymer P(VDF-TrFE) in the position sensitive detector makes the instantaneous photovoltage (LPV) of the position sensitive detector after the pyroelectric field is introduced photo+pyro ) compared to the transient stable photovoltage (LPV) generated by the lateral photovoltaic effect photo) value increased by more than 1.4 times, obtaining higher signals and better responses. The nonlinearity of the position-sensitive detector is controlled within 8.5%, the highest position sensitivity reaches 688.10mV / mm, and the measurable wavelength range is 405-1064nm. The position-sensitive detector combines the binary encoding of the laser 7 irradiation position with the lateral photovoltage response at a specific wavelength to achieve wavelength-resolved photoelectric demodulation in the visible-near infrared range (405-1064nm). The MAPbI in the position-sensitive detector 3 :The P(VDF-TrFE) / Si heterojunction position-sensitive detector exhibits excellent photoelectric response characteristics under different wavelengths, irradiation positions and laser intensities, and can also effectively detect multi-dimensional optical information of wavelength, position and light intensity through the photovoltage enhancement ratio generated by the pyroelectric effect.

[0056] In one example of the present invention, the MAPbI 3 : The thickness of the P(VDF-TrFE) composite thin film light absorbing layer 2 is 80-1100nm.

[0057] For example, the MAPbI 3 :The thickness of the P(VDF-TrFE) composite thin film light absorbing layer 2 is 80nm, 110nm, 265nm, 340nm, 600nm and 1100nm.

[0058] In one example of the present invention, the transparent conductive layer 3 is an ITO conductive layer, and its thickness is 10-30 nm;

[0059] Preferably, the ITO conductive layer is 20 nm thick.

[0060] In an example of the present invention, the first electrode 4 and the second electrode 5 are silver electrodes, and their cross sections are both square structures with side lengths not exceeding 1 mm, and the spacing between the first electrode 4 and the second electrode 5 is 0.4-1 mm.

[0061] According to the second aspect of the present invention, a method for preparing a position sensitive detector based on a heterojunction as described above comprises the following steps:

[0062] S10: ultrasonically clean the silicon substrate with acetone, ethanol and deionized water in sequence, and dry it for later use;

[0063] S20: Place the silicon substrate in a mixed solution of hydrofluoric acid and water to remove the surface SiO 2 layer;

[0064] S30: Add the perovskite precursor solution to the surface of the silicon substrate layer 1 to form MAPbI 3: P(VDF-TrFE) composite thin film light absorbing layer 2, after standing at room temperature, annealing treatment is performed on a heating table;

[0065] S40: MAPbI 3 : The P (VDF-TrFE) composite thin film light absorbing layer 2 is placed in a magnetron sputtering chamber and evacuated, and then argon gas is introduced to maintain the pressure in the chamber at a first specified pressure, and a transparent conductive layer 3 is magnetron sputtered using ITO as a target;

[0066] S50: placing the transparent conductive layer 3 in a magnetron sputtering chamber and evacuating the chamber, then introducing argon gas to maintain the pressure in the chamber at a second specified pressure, and performing magnetron sputtering with a metal as a target to form a first electrode 4 and a second electrode 5;

[0067] This preparation method is based on the perovskite MAPbI 3 The addition of polymer P(VDF-TrFE) to the device improves the photoresponse of the device by regulating the surface resistance of the position-sensitive detector. Compared with the undoped MAPbI 3 The response signal of the film layer is greatly improved, a higher signal is obtained, and the detection is more sensitive; the composite perovskite film MAPbI 3 : P(VDF-TrFE) combines with Si to form a pn junction, which expands the detection range to 405nm-1064nm. The introduction of the pyroelectric polymer P(VDF-TrFE) in the preparation method makes the instantaneous photovoltage (LPV) of the position sensitive detector after the pyroelectric field is introduced photo+pyro ) compared to the transient stable photovoltage (LPV) generated by the lateral photovoltaic effect photo ) value increased by more than 1.4 times, obtaining a higher signal and better response. The nonlinearity of the preparation method was controlled within 8.5%, the highest position sensitivity reached 688.10mV / mm, and the measurable wavelength range was 405-1064nm.

[0068] In one example of the present invention, in step S30, the preparation of the perovskite precursor solution includes the following steps:

[0069] S31: dissolving a certain amount of P(VDF-TrFE) in N,N-dimethylformamide solution;

[0070] S32: PbI 2 With CH 3 NH 3 I is added to the above P(VDF-TrFE) solution at a specified molar ratio to form a perovskite precursor solution.

[0071] In an example of the present invention, in step S31, 0-25 mg of P(VDF-TrFE) is dissolved in 250 μL of N,N-dimethylformamide solution.

[0072] In one example of the present invention, in step S32, PbI 2 With CH 3 NH 3 I is added to the P(VDF-TrFE) solution at a molar ratio of 1:1 to form a perovskite precursor solution, and the prepared perovskite precursor solution is magnetically stirred at room temperature to make the concentration of P(VDF-TrFE) reach 0-1wt%.

[0073] For example, the perovskite precursor solution was magnetically stirred at room temperature to uniformly obtain P(VDF-TrFE) concentrations of 0, 0.2, 0.4, 0.6, 0.8 and 1 wt%.

[0074] In one example of the present invention, in step S50, the perovskite precursor solution is dropped onto the surface of the substrate by spin coating to form MAPbI 3 :P(VDF-TrFE) composite thin film light absorbing layer 2, after spin coating, let it stand at room temperature, and then put it on a heating table preheated to 80-90℃ for annealing for 5-7h.

[0075] According to the third aspect of the present invention, an application of a position sensitive detector based on a heterojunction prepared by the above-mentioned preparation method is applied to wavelength-resolved demodulation.

[0076] A plurality of position points P are marked on the surface of the position sensitive detector. i When the laser 7 is irradiated at these positions in sequence, the sensitive detector generates different lateral photovoltaic voltage values. i Binary encoding is performed to obtain binary signals output by the position sensitive detector according to the order of the irradiation positions of the laser 7.

[0077] Four positions P1, P2, P3 and P4 are marked on the surface of the position-sensitive detector. When the laser 7 is irradiated at these positions in sequence, the device can generate different lateral photovoltaic voltage values, which can be represented by binary codes, and P1, P2, P3 and P4 correspond to the codes of "00", "01", "10" and "11" respectively. When the laser 7 irradiates positions P2, P1, P3 and P1 in sequence, the binary signal output by the position-sensitive detector is "01001000", which is demodulated by ASCII code to obtain the letter "H". Figure 6As shown in the figure, by measuring the lateral photovoltage value under different wavelengths of light (405nm, 532nm, 671nm, 780nm and 1064nm), the device obtained response values ​​of 400mV, 460mV, 520mV, 624mV and 370mV respectively. These data combined with position coding successfully demodulated the "HBU", reflecting the application potential of this position-sensitive detector in wavelength-resolved demodulation.

[0078] The position-sensitive detector combines the binary coding of the laser 7 irradiation position with the lateral photovoltage response at a specific wavelength, achieving wavelength-resolved photoelectric demodulation in the visible-near infrared range (405-1064nm).

[0079] According to the fourth aspect of the present invention, an application of a position sensitive detector based on a heterojunction prepared by the preparation method as described above is provided, wherein the position sensitive detector is applied to multi-dimensional optical information detection.

[0080] like Figure 7 As shown in the figure, four different irradiation positions were selected, namely X1 (-0.08mm), X2 (-0.16mm), X3 (-0.24mm) and X4 (-0.30mm), and the LPV response under laser irradiation with wavelengths ranging from 405nm to 1064nm and light intensities ranging from 0.01mW to 10mW was systematically studied. The voltage enhancement ratio (LPV) caused by the pyroelectric effect was extracted and analyzed. photo+pyro -LPV photo ) / LPV photo )like Figure 8 As shown, it increases with the increase of the incident power of laser 7, especially near the center of the device, the enhancement ratio is more significant. Under the irradiation of 780nm wavelength and 10mW laser 7, the enhancement ratios of positions P1 to P4 are 144.82%, 55.81%, 27.55% and 14.70% respectively; at 405nm wavelength, the enhancement ratios are 49.69%, 13.63%, 5.68% and 3.90% respectively; at 532nm wavelength, they are 53.08%, 16.98%, 7.65% and 4.59% respectively; at 671nm wavelength, they are 86.80%, 27.55%, 10.60% and 7.32% respectively; at 1064nm wavelength, they are 122.41%, 47.46%, 23.83% and 15.53% respectively. The variation characteristics of the lateral photovoltage enhancement ratio under different wavelengths, light intensities and irradiation positions show that MAPbI 3 :P(VDF-TrFE) / Si heterojunction position-sensitive detector can effectively respond to multidimensional optical signals and has the potential for multidimensional optical information detection.

[0081] MAPbI in this position-sensitive detector 3:The P(VDF-TrFE) / Si heterojunction position-sensitive detector exhibits excellent photoelectric response characteristics under different wavelengths, irradiation positions and laser intensities, and can also effectively detect multi-dimensional optical information of wavelength, position and light intensity through the photovoltage enhancement ratio generated by the pyroelectric effect.

[0082] In order to verify the sensitivity of the position sensitive detector, the following two experimental devices are used for verification:

[0083] Example 1

[0084] like Figure 1 As shown, the experimental device includes: a position sensitive detector, a laser 7 and a voltmeter 6, wherein the voltmeter 6 is connected in series between the first electrode 4 and the second electrode 5, and the light spot emitted by the laser 7 moves between the first electrode 4 and the second electrode 5;

[0085] The method for preparing the position sensitive detector involved in the experimental device comprises the following steps:

[0086] a. A 500 μm thick n-Si single crystal substrate was ultrasonically treated with acetone, ethanol and deionized water for 20 min each. The silicon wafer was placed in a 1:4 (hydrofluoric acid: water) solution to remove the surface SiO 2 layer.

[0087] b. Dissolve different amounts of P(VDF-TrFE) (0, 5, 10, 15, 20, 25 mg) in 250 μL N,N-dimethylformamide (DMF) to prepare solutions of different concentrations. Next, 18.6 mg of lead iodide (PbI 2 ) and 6.4 mg iodine methylamine (CH 3 NH 3 I) mixed and dissolved in P(VDF-Tr FE) solution at a molar ratio of 1:1 to form a perovskite precursor solution, so that the concentration of P(VDF-TrFE) reached 0, 0.2, 0.4, 0.6, 0.8 and 1 wt%. The obtained mixture was stirred at room temperature for 24 h to ensure full dissolution.

[0088] c. Si substrate is placed in a N 2 The glove box was fixed to the suction cup of the coating machine, and 35 μL of the perovskite precursor solution was slowly dripped onto the surface of the Si substrate at a speed of 4000 r / min for 20 seconds. After the spin coating was completed, it was left to stand at room temperature for 10 minutes, and then placed on a heating table preheated to 90°C for annealing for 6 hours to obtain MAPbI 3 :P(VDF-TrFE) composite film.

[0089] d. After the sample is placed in the magnetron sputtering chamber, a mechanical pump is used to evacuate the chamber. When the vacuum degree reaches below 10Pa, a molecular pump is used to evacuate the chamber. Wait until the vacuum degree in the sputtering chamber reaches 1×10 -5 Pa. Fill the sputtering chamber with argon gas at a certain flow rate through the inlet valve, and then adjust the molecular pump gate valve to maintain the pressure in the sputtering chamber at 0.4Pa, and adjust the sputtering power to 40W. After adjusting the film growth conditions, pre-sputter for five or six minutes to ensure that the glow in the chamber is stable, the film is deposited at a certain rate, and the obtained film is dense and uniform. After the glow is stable, remove the substrate baffle and start formal sputtering. When the timing reaches 3 minutes, a 20nm thick ITO conductive layer is obtained. Close the baffle; after the growth is completed, turn off the vacuum system, close the gate valve and the solenoid valve, fill with nitrogen so that the pressure in the chamber is atmospheric pressure, open the chamber door and take out the sample.

[0090] e. After the sample is placed in the magnetron sputtering chamber, a mechanical pump is used to evacuate the chamber. When the vacuum degree reaches below 10Pa, a molecular pump is used to evacuate the chamber. Wait until the vacuum degree in the sputtering chamber reaches 1×10 -5 Pa. Fill the sputtering chamber with argon gas at a certain flow rate through the inlet valve, and then adjust the molecular pump gate valve to maintain the pressure in the sputtering chamber at 1Pa, and adjust the sputtering power to 14W. After adjusting the film growth conditions, pre-sputter for five or six minutes to ensure that the glow in the chamber is stable, the film is deposited at a certain rate, and the obtained film is dense and uniform. After the glow is stable, remove the substrate baffle and start formal sputtering. When the timing reaches 13 minutes, a 50nm thick Ag electrode is obtained. Close the baffle; after the growth is completed, turn off the vacuum system, close the gate valve and the solenoid valve, fill with nitrogen so that the pressure in the chamber is atmospheric pressure, open the chamber door and take out the sample.

[0091] f. Use the indium pressing method to lead the wires from the first electrode 4 and the second electrode 5 and connect them to the voltmeter 6.

[0092] The 780nm laser 7 point light source is irradiated on the surface of the position sensitive detector with different P(VDF-TrFE) concentrations, and moved between the first electrode 4 and the second electrode 5 to perform the lateral photovoltaic effect test. The relationship between the lateral photovoltage and the position of the laser 7 can be obtained, as shown in FIG. Figure 3 The wavelength of laser 7 is changed, and the test object is a position sensitive detector with a doping concentration of 0.2wt%. The above operation is repeated to obtain the change of lateral photovoltage with the wavelength of laser 7, as shown in Figure 4 The obtained lateral photovoltage curve with the position of the laser beam 7 shows that the MAPbI 3 :P(VDF-TrFE) / Si heterojunction device has a higher response signal of the optical position sensitive detector within the measured range.

[0093] pass Figure 3 It can be seen that when the laser power is adjusted to 10 mW, as the concentration of P(VDF-TrFE) increases, the lateral photovoltage increases first and then decreases. At a concentration of 0.2 wt%, the lateral photovoltage signal is the strongest, reaching 83 mV. Figure 4 It can be seen that with the increase of the wavelength of laser 7, the lateral photovoltage also shows a trend of first increasing and then decreasing. At a wavelength of 780nm, the lateral photovoltage signal is the strongest.

[0094] Example 2

[0095] like Figure 2 As shown, the experimental device includes: a position sensitive detector, a laser 7, an oscilloscope 9 and a chopper 8, wherein the oscilloscope 9 is connected in series between the first electrode 4 and the second electrode 5, the light spot emitted by the laser 7 is at a fixed point between the first electrode 4 and the second electrode 5, and the chopper 8 is set on the path of the laser 7 and is configured to convert the continuous laser 7 into periodic pulse light.

[0096] The preparation method of the position sensitive detector involved in the experimental device includes the following steps:

[0097] a. A 500 μm thick n-Si single crystal substrate was ultrasonically treated with acetone, ethanol and deionized water for 20 min each. The silicon wafer was placed in a 1:4 (hydrofluoric acid: water) solution to remove the surface SiO 2 layer.

[0098] b. Dissolve 5 mg of P(VDF-TrFE) in 250 μL N,N-dimethylformamide (DMF) to prepare a solution. Next, add 18.6 mg of lead iodide (PbI 2 ) and 6.4 mg iodine methylamine (CH 3 NH 3 I) mixed and dissolved in P(VDF-TrFE) solution at a molar ratio of 1:1 to form a perovskite precursor solution, so that the concentration of P(VDF-TrFE) reaches 0.2wt%. The obtained mixture is stirred at room temperature for 24h to ensure full dissolution.

[0099] c. Si substrate is placed in a N 2 The glove box was fixed to the suction cup of the coating machine, and 35 μL of the perovskite precursor solution was slowly dripped onto the surface of the Si substrate at a speed of 4000 r / min for 20 seconds. After the spin coating was completed, it was left to stand at room temperature for 10 minutes, and then placed on a heating table preheated to 90°C for annealing for 6 hours to obtain MAPbI 3 :P(VDF-TrFE) composite film.

[0100] d. After the sample is placed in the magnetron sputtering chamber, a mechanical pump is used to evacuate the chamber. When the vacuum degree reaches below 10Pa, a molecular pump is used to evacuate the chamber. Wait until the vacuum degree in the sputtering chamber reaches 1×10 -5 Pa. Fill the sputtering chamber with argon gas at a certain flow rate through the inlet valve, and then adjust the molecular pump gate valve to maintain the pressure in the sputtering chamber at 0.4Pa, and adjust the sputtering power to 40W. After adjusting the film growth conditions, pre-sputter for five or six minutes to ensure that the glow in the chamber is stable, the film is deposited at a certain rate, and the obtained film is dense and uniform. After the glow is stable, remove the substrate baffle and start formal sputtering. When the timing reaches 3 minutes, a 20nm thick ITO conductive layer is obtained. Close the baffle; after the growth is completed, turn off the vacuum system, close the gate valve and the solenoid valve, fill with nitrogen so that the pressure in the chamber is atmospheric pressure, open the chamber door and take out the sample.

[0101] e. After the sample is placed in the magnetron sputtering chamber, a mechanical pump is used to evacuate the chamber. When the vacuum degree reaches below 10Pa, a molecular pump is used to evacuate the chamber. Wait until the vacuum degree in the sputtering chamber reaches 1×10 -5 Pa. Fill the sputtering chamber with argon gas at a certain flow rate through the inlet valve, and then adjust the molecular pump gate valve to maintain the pressure in the sputtering chamber at 1Pa, and adjust the sputtering power to 14W. After adjusting the film growth conditions, pre-sputter for five or six minutes to ensure that the glow in the chamber is stable, the film is deposited at a certain rate, and the obtained film is dense and uniform. After the glow is stable, remove the substrate baffle and start formal sputtering. When the timing reaches 13 minutes, a 50nm thick Ag electrode is obtained. Close the baffle; after the growth is completed, turn off the vacuum system, close the gate valve and the solenoid valve, fill with nitrogen so that the pressure in the chamber is atmospheric pressure, open the chamber door and take out the sample.

[0102] f. Using the indium pressing method, the wires are led out from the first electrode 4 and the second electrode 5 and connected to the oscilloscope 9.

[0103] A 780nm laser 7 point light source is irradiated on the surface of a position sensitive detector with a P(VDF-TrFE) concentration of 0.2wt%, and a chopper 8 is added between the laser 7 and the position sensitive detector. The irradiation position of the laser 7 is adjusted and fixed. The laser 7 is irradiated and the power of the laser 7 is adjusted. The oscilloscope 9 can display the transient response lateral photovoltage of this position sensitive detector. After data processing and analysis, the transient stable photovoltage (LPV) generated by the lateral photovoltaic effect of this position sensitive detector under different laser 7 powers is obtained. photo ) and the instantaneous photovoltage (LPV) after the introduction of the pyroelectric field photo+pyro ),like Figure 5 shown.

[0104] pass Figure 5 It can be seen that the photovoltage LPV photoand LPV photo+pyro The lateral photovoltage increases with the increase of laser 7 power and reaches the maximum when the laser 7 power is 10 mW, which are 22.50 and 55.05 mV respectively. The lateral photovoltage is increased by more than 1.4 times by introducing the pyroelectric field.

[0105] The exemplary implementation schemes of the heterojunction-based position-sensitive detector, preparation method and application thereof proposed in the present invention are described in detail above with reference to the preferred embodiments. However, it can be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations can be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the present invention can be combined in various ways without exceeding the protection scope of the present invention, which is determined by the attached claims.

Claims

1. A position sensitive detector based on a heterojunction, characterized in that: It comprises a silicon substrate layer (1), a MAPbI3:P(VDF-TrFE) composite thin film light absorbing layer (2) and a transparent conductive layer (3) which are arranged in sequence from bottom to top, wherein a first electrode (4) and a second electrode (5) are arranged at intervals on the end surface of the transparent conductive layer (3) which is away from the MAPbI3:P(VDF-TrFE) composite thin film light absorbing layer (2); The silicon substrate layer (1) and the MAPbI3:P(VDF-TrFE) composite thin film light absorbing layer (2) form a MAPbI3:P(VDF-TrFE) / Si heterojunction.

2. The heterojunction-based position sensitive detector according to claim 1, characterized in that: The thickness of the MAPbI3:P(VDF-TrFE) composite thin film light-absorbing layer (2) is 80-1100 nm.

3. The heterojunction-based position sensitive detector according to claim 1, characterized in that: The transparent conductive layer (3) is an ITO conductive layer, and its thickness is 10-30 nm.

4. The heterojunction-based position sensitive detector according to claim 1, characterized in that: The first electrode (4) and the second electrode (5) are silver electrodes, and their cross sections are both square structures with side lengths not exceeding 1 mm, and the spacing between the first electrode (4) and the second electrode (5) is 0.4-1 mm.

5. A method for preparing a position sensitive detector based on a heterojunction according to any one of claims 1 to 4, characterized in that: The steps include: S10: ultrasonically clean the silicon substrate with acetone, ethanol and deionized water in sequence, and dry it for later use; S20: placing the silicon substrate in a mixed solution of hydrofluoric acid and water to remove the surface SiO2 layer; S30: adding a perovskite precursor solution to the surface of the silicon substrate layer (1) to form a MAPbI3:P(VDF-TrFE) composite thin film light absorbing layer (2), and then annealing the mixture on a heating table after standing at room temperature; S40: placing the MAPbI3:P(VDF-TrFE) composite thin film light absorbing layer (2) in a magnetron sputtering chamber and evacuating the chamber, then introducing argon gas to maintain the pressure in the chamber at a first specified pressure, and magnetron sputtering a transparent conductive layer (3) using ITO as a target material; S50: placing the transparent conductive layer (3) in a magnetron sputtering chamber and evacuating the chamber, then introducing argon gas to maintain the pressure in the chamber at a second specified pressure, and performing magnetron sputtering with a metal as a target material to form a first electrode (4) and a second electrode (5).

6. The method for preparing a position sensitive detector based on a heterojunction according to claim 5, characterized in that: In step S30, the preparation of the perovskite precursor solution includes the following steps: S31: dissolving a certain amount of P(VDF-TrFE) in N,N-dimethylformamide solution; S32: PbI2 and CH3NH3I are added to the above P(VDF-TrFE) solution in a specified molar ratio to form a perovskite precursor solution.

7. The method for preparing a position sensitive detector based on a heterojunction according to claim 6, characterized in that: In the step S32, PbI2 and CH3NH3I are added to the P(VDF-TrFE) solution in a molar ratio of 1:1 to form a perovskite precursor solution, and the prepared perovskite precursor solution is magnetically stirred at room temperature to make the P(VDF-TrFE) concentration reach 0-1wt%.

8. The method for preparing a position sensitive detector based on a heterojunction according to claim 5, characterized in that: In the step S50, the perovskite precursor solution is dripped onto the substrate surface by spin coating to form a MAPbI3:P(VDF-TrFE) composite thin film light absorbing layer (2). After spin coating, the solution is allowed to stand at room temperature and then placed on a heating table preheated to 80-90° C. for annealing for 5-7 hours.

9. An application of a position sensitive detector based on a heterojunction prepared by the preparation method according to any one of claims 5 to 8, characterized in that: The position sensitive detector is applied to wavelength-resolved demodulation.

10. An application of a position sensitive detector based on a heterojunction prepared by the preparation method according to any one of claims 5 to 8, characterized in that: The position sensitive detector is applied to multi-dimensional optical information detection.

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