A tin-lead perovskite photodetector based on introduction of guanidinium and strontium ions and a preparation method thereof

Abstract

A kind of tin lead perovskite photodetector based on introducing guanidinium ion and strontium ion and preparation method thereof, belong to perovskite photoelectric device technical field.The photodetector described in the application is composed of ITO conductive glass anode, PTAA anode buffer layer, tin lead perovskite film introducing guanidinium ion and strontium ion, C 60 / BCP cathode buffer layer, Cu cathode from bottom to top. + When A-site cation is doped with ion in perovskite, the carrier lifetime of perovskite material can be improved, and the open-circuit voltage of the device can be improved, the carrier diffusion length can be increased, the defects can be reduced, and the stability of the device can be improved;Sr 2+ Doping with ion in B-site of perovskite can increase conductivity, improve stability and optimize electrode performance, ultimately achieve the effect of passivating defects, reducing the capture of electrons by traps and improving photoelectric conversion efficiency, and the optimization effect mainly reflects on light and dark current and external quantum efficiency, and a high-performance photodetector is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite photoelectric devices, and particularly relates to a tin-lead perovskite photoelectric detector based on introduction of guanidinium ions and strontium ions and a preparation method thereof. BACKGROUND

[0002] As a device for directly converting optical signals into electrical signals by using photoelectric effect, the photoelectric detector is widely applied in various fields such as military defense, environmental monitoring, medical communication and the like. For example, in the ultraviolet light band, the photoelectric detector is mainly used for national defense, forest fire warning and the like; in the visible light or near-infrared band, the photoelectric detector is mainly applied to imaging, photometric measurement and automatic control and the like; and in the infrared band, the photoelectric detector is mainly applied to missile guidance, infrared imaging and remote sensing and the like. With the continuous progress of science and technology, new demands are put forward for the spectrum, flexibility and performance of the photoelectric detector, and the diversification of demands makes it difficult for the traditional photoelectric detector represented by silicon to meet the demands. Therefore, it is necessary to develop a new type of photoelectric detector to make up for the shortcomings of the traditional photoelectric detector.

[0003] The perovskite material has photoelectric properties such as high absorption coefficient, high mobility, adjustable band gap and long carrier diffusion length, and the photoelectric detector prepared by the perovskite material has advantages such as low cost, light weight, easy processing and bendability, and therefore attracts widespread attention. However, at present, the perovskite material cannot detect infrared light due to the limitation of the band gap, and the infrared light detection has a wide application in fields such as medical imaging and communication technology, which seriously restricts the application potential of the perovskite photoelectric detector. A method for expanding the absorption spectrum of the perovskite photoelectric detector is to dope part of divalent tin elements, so that the absorption edge of the perovskite can be expanded to the near-infrared region. SUMMARY

[0004] The application aims to provide a tin-lead perovskite photoelectric detector based on introduction of guanidinium ions and strontium ions and a preparation method thereof.

[0005] The photoelectric detector designed in the application is composed of, from bottom to top, an ITO conductive glass anode, a PTAA (poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine)) anode buffer layer, a tin-lead perovskite film based on introduction of guanidinium ions and strontium ions, a C 60 / BCP cathode buffer layer and a Cu cathode.

[0006] The tin-containing perovskite is characterized by the existence of p-doping from intrinsic, extrinsic and the like, which greatly affects many key photoelectric properties of the perovskite device, such as the light dark current and the external quantum efficiency. In addition, due to the characteristics of tin ions, the universal existence of various defects in the absorption layer can cause non-radiative trapping recombination of charge carriers, thereby reducing the performance of the tin-based perovskite device. Therefore, any attempt to improve the photoelectric performance of the tin-based perovskite device is mainly aimed at the control of doping and defect passivation. The present application proposes a strategy of introducing guanidinium ions (GA + ) and strontium ions (Sr 2+ ), and the doping ions can effectively fill the interface and surface of the perovskite layer, the GA + ion doping in the A-site cation of the perovskite can improve the carrier lifetime of the perovskite material and the open-circuit voltage of the device, and can also increase the carrier diffusion length, reduce defects, and improve the stability of the device; the Sr 2+ ion doping in the B-site of the perovskite can increase the conductivity, improve the stability, and optimize the electrode performance, so as to passivate defects, reduce the capture of electrons by traps, and improve the photoelectric conversion efficiency, and the optimization effect is mainly reflected in the light dark current and the external quantum efficiency.

[0007] The preparation method of the tin-lead perovskite photodetector based on the introduction of guanidinium ions and strontium ions comprises the following steps:

[0008] (1) clean ITO conductive glass (250-350mm 2 ) with acetone, anhydrous ethanol and deionized water for 10-40min, then dry the ITO conductive glass with nitrogen to obtain clean ITO conductive glass, and then treat the ITO conductive glass with ozone ultraviolet for 30-40min to obtain ITO conductive glass anode;

[0009] (2) dissolve 4-8mg of PTAA in 2-4mL of toluene, and stir for 20-24h under the condition that the water oxygen content is less than 0.01PPm; then, in a nitrogen glove box or in an air environment, use a spin coater to uniformly spin coat the PTAA toluene solution on the ITO conductive glass anode, the spin coating speed is 3500-4500rpm, and the spin coating time is 35-45s, and then anneal on a hot stage at 90-110℃ for 10-15min, so as to obtain a 20-40nm thick PTAA anode buffer layer on the ITO conductive glass anode;

[0010] (3) mix DMF and DMSO according to a volume ratio of 4:1 to obtain a mixed solvent; mix raw materials FAI, PbI2, SnI2, GAI, SrI2 and CsI according to a tin-lead perovskite Cs 0.1 FA 0.85 GA0.05 Sr 0.002 Pb 0.499 Sn 0.499 I3 stoichiometric ratio is added to the mixed solvent, and then stirred in a glove box filled with nitrogen and water oxygen content below 0.01PPm for 20-24h to obtain a perovskite precursor solution with a concentration of 1-1.5mol / L; then 90-120μL of DMF is added dropwise on the PTAA anode buffer layer on the spin coater in the glove box filled with nitrogen at 800-1200rpm, and after 10-15s of spin coating, 60-90μL of perovskite precursor solution is spin-coated on the PTAA anode buffer layer, the spin coater speed is set to 3500-4500rpm, and the spin coating time is 25-40s, and 250-350μL of anti-solvent chlorobenzene is added dropwise when the spin coating time is left for 10-15s; after spin coating, the device is transferred to a hot stage and annealed at 80-120℃ for 10-15min, thereby obtaining a high-quality, well-formed Cs 0.1 FA 0.85 GA 0.05 Sr 0.002 Pb 0.499 Sn 0.499 I3 tin-lead perovskite film;

[0011] (4) using a multi-source organic gas phase molecular deposition system, under a vacuum with a pressure not higher than 7×10 -4 Pa, evaporating a C 60 layer with a thickness of 20-40nm on the tin-lead perovskite film, and then evaporating a BCP layer with a thickness of 5-10nm on the C 60 layer, to obtain a C 60 / BCP cathode buffer layer;

[0012] (5) using a multi-source organic gas phase molecular deposition system, under a vacuum with a pressure not higher than 7×10 -4 Pa, evaporating a Cu cathode with a thickness of 80-90nm on the C 60 / BCP cathode buffer layer, thereby preparing the tin-lead perovskite photodetector based on the introduction of guanidinium ions and strontium ions. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 : the structure of the tin-lead perovskite photodetector based on the introduction of guanidinium ions and strontium ions according to the present application; from bottom to top, there are ITO conductive glass anode, PTAA anode buffer layer, tin-lead perovskite film with guanidinium ions and strontium ions, C 60 / BCP cathode buffer layer and Cu cathode;

[0014] Figure 2: Light absorption characteristic curves of the tin-lead perovskite films prepared in Comparative Example 2 and Example 1; the response spectra of the two tin-lead perovskite films of Comparative Example 2 (curve ①) and Example 1 (curve ②) both cover the range of 300 to 1100 nm and extend into the near-infrared region, providing a practical basis for realizing a wide-spectrum photodetector for visible light and near-infrared light;

[0015] Figure 3 : Cs prepared in Comparative Example 1, Comparative Example 2 and Experimental Example 1 0.15 FA 0.85 Pb 0.5 Sn 0.5 I3、Cs 0.1 FA 0.85 GA 0.05 Pb 0.5 Sn 0.5 I3 and Cs 0.1 FA 0.85 GA 0.05 Sr 0.002 Pb 0.499 Sn 0.499 The external quantum efficiency (EQE) curve of the photodetector of I3 tin-lead perovskite film; It can be seen that the comparative example 2 ( Figure 3 (a) curve ②), Example 1 with the addition of guanidine ions and strontium ions ( Figure 3 The curve ② of (b) is better than that of the comparative example 1 ( Figure 3 Curve ① of (a) shows a higher external quantum efficiency, while that of Comparative Example 2 ( Figure 3 Curve ② of (a) is mainly improved in the range of 400 to 1000 nm, with the conversion efficiency exceeding 75% at around 550 nm and exceeding 55% at around 900 nm. Figure 3 (b) Curve ②) is compared with Comparative Example 2 ( Figure 3 Curve ① in (b) shows significant improvements between 400 and 750 nm, with the EQE approaching 80% at around 580 nm and exceeding 60% at around 900 nm. This demonstrates that the SnPb perovskite photodetector fabricated by the method described herein, which incorporates guanidine and strontium ions, exhibits excellent photoelectric conversion capabilities.

[0016] Figure 4 : JV characteristic curves of the tin-lead perovskite photodetectors prepared in Comparative Example 1, Comparative Example 2 and Experimental Example 1 under light and dark conditions, the voltage scanning range is -400 to 1200 mV, and the horizontal and vertical coordinates of the data image are processed logarithmically; it can be seen that Comparative Example 2 ( Figure 4 The dark current of curve ② of (a) is significantly lower than that of comparative example 1 ( Figure 4 The curve ① of (a) is obviously reduced by one order of magnitude, and the comparative example 2 ( Figure 4(a) of curve ③) photocurrent compared with Comparative Example 1 Figure 4 (a) of curve ④) reflects the characteristics of stronger light response of the device. Example 1 Figure 4 (b) of curve ②) dark current is lower than Comparative Example 2 Figure 4 (b) of curve ①) continues to decrease by an order of magnitude, reaching 10 -5 ; Comparative Example 2 Figure 4 (b) of curve ③) photocurrent compared with Comparative Example 1 Figure 4 (b) of curve ④) also reflects the characteristics of stronger light response, which shows that the device doped with guanidinium and strontium ions significantly reduces the voltage loss, increases the open circuit voltage, and obtains a more superior photodetector.

[0017] Figure 5 : Noise current test curves of tin-lead perovskite materials prepared by Comparative Example 1, Comparative Example 2 and Example 1; from the figure, Comparative Example 2 Figure 5 (a) of curve ②) is lower than Comparative Example 1 Figure 5 (a) of curve ①) noise current is reduced by two orders of magnitude, Example 1 Figure 5 (b) of curve ②) is lower than Comparative Example 2 Figure 5 (b) of curve ①) noise current is as low as 10 -13 , further proving that the existence of guanidinium and strontium ions reduces the defects of the perovskite layer and obtains an excellent perovskite photodetector.

[0018] Figure 6 : EQE response curves of tin-lead perovskite materials prepared by Comparative Example 2 and Example 1 at different times; wherein the EQE of Comparative Example 2 is selected at 1 day Figure 6 (a) of curve ①), 3 days Figure 6 (a) of curve ②) and 7 days Figure 6 (a) of curve ③), and the EQE of Example 1 is selected at 1 day Figure 6 (b) of curve ①), 3 days Figure 6 (b) of curve ②) and 7 days Figure 6 (b) of curve ③). From the figure, the EQE response decreases with time, the EQE of Comparative Example 2 Figure 6 (a) decreases by about 10% after 7 days, still maintaining a relatively high device performance; the peak value of the EQE of Example 1 Figure 6 (b) still maintains at 70% after 7 days, while the peak value of the EQE of Comparative Example 2 is lower than 70%, further proving that the existence of guanidinium and strontium ions improves the stability of the device.

[0019] Figure 7: Atomic force microscope images of photodetectors of tin-lead perovskite thin films prepared in Comparative Example 1, Comparative Example 2 and Example 1; it can be seen that the tin-lead perovskite thin film of Comparative Example 1 Figure 7 (a) without doping, the surface of the original control tin-lead perovskite thin film is relatively rough, the average surface roughness (RMS) is about 18.8 nm, Comparative Example 1 Figure 7 (b) after adding guanidinium ion doping, the average surface roughness is 15.8 nm, Example 1 Figure 7 (c) after adding guanidinium ion and strontium ion, the average surface roughness is 13.2 nm. Such obvious reduction in surface roughness effectively proves that the film forming ability is improved by doping guanidinium ion and strontium ion, which further enhances the electron extraction and reduces the carrier recombination due to interface defects. DETAILED DESCRIPTION

[0020] Comparative Example 1:

[0021] (1) ITO conductive glass (20*15mm, area 300mm 2 ) was sequentially cleaned with acetone for 30 min, anhydrous ethanol for 20 min, and deionized water for 10 min under ultrasonic, and then dried with nitrogen to obtain clean ITO conductive glass, which was treated with ultraviolet ozone for 30 min to obtain ITO conductive glass anode;

[0022] (2) 4 mg of PTAA was dissolved in 2 mL of toluene, and the solution was stirred for 24 h under room temperature in a nitrogen atmosphere with water oxygen content less than 0.01 PPM to obtain a toluene solution of PTAA. Then, the toluene solution of PTAA was uniformly spin-coated on the ITO conductive glass anode in a nitrogen glove box, and the parameters of the spin coater were as follows: spin coating speed 4000 rpm, spin coating acceleration 2000 rpm, spin coating time 40 s. After spin coating, the ITO conductive glass anode was placed on a preheated hot plate and annealed at 100°C for 10 min to obtain a 30 nm PTAA anode buffer layer on the ITO conductive glass anode;

[0023] (3) First, a tin-lead perovskite precursor solution was prepared. DMF and DMSO were mixed in a volume ratio of 4:1 to obtain a mixed solvent. Raw materials FAI, PbI2, SnI2 and CsI were added to the mixed solvent in a molar ratio of Cs 0.15 FA 0.85 Pb 0.5 Sn 0.5I3 stoichiometric ratio is added to the mixed solvent, and a perovskite precursor solution with a concentration of 1.5 mol / L is obtained by stirring in a glove box filled with nitrogen with a water oxygen content of less than 0.01 ppm for 24 h. Then, in a glove box filled with nitrogen with a water oxygen content of less than 0.01 ppm, the parameters of the spin coater are set as follows: the spin coating speed is 1000 rpm, the spin coating acceleration is 500 rpm, and the spin coating time is 10 s. 100 μL of DMF is spin coated on the PTAA anode buffer layer. After spin coating for 10 s, 70 μL of the perovskite precursor solution is spin coated on the PTAA anode buffer layer. The parameters of the spin coater are set as follows: the spin coating time is 30 s, the spin coating speed is 4000 rpm, and the spin coating acceleration is 2000 rpm. 300 μL of anti-solvent chlorobenzene is added at the remaining 15 s of the spin coating time. After spin coating, the device is transferred to a preheated hot plate and annealed at 100°C for 10 min to obtain a Cs 0.15 FA 0.85 Pb 0.5 Sn 0.5 I3 tin-lead perovskite film;

[0024] (4) Using a multi-source organic vapor phase molecular deposition system, a 20 nm thick C -4 layer is evaporated on the tin-lead perovskite film under a pressure of not more than 7 x 10 60 Pa, and then a 7 nm thick BCP layer is evaporated on the C 60 layer to obtain a C 60 / BCP cathode buffer layer;

[0025] (5) Using a multi-source organic vapor phase molecular deposition system, 80 nm thick Cu is evaporated as a cathode on the C -4 / BCP cathode buffer layer under a pressure of not more than 7 x 10 60 Pa, thereby preparing a tin-lead perovskite photodetector.

[0026] Comparative Example 2:

[0027] (1) The ITO conductive glass (20*15 mm, with an area of 300 mm 2 ) is sequentially cleaned with acetone for 30 min, ethanol for 20 min, and deionized water for 10 min under ultrasonic waves, and then dried with nitrogen to obtain dry and clean ITO conductive glass. The ITO conductive glass is then treated with ultraviolet ozone for 30 min to obtain an ITO anode;

[0028] (2) 4 mg of PTAA was dissolved in 2 mL of toluene and stirred for 24 h under the conditions of nitrogen and water oxygen content less than 0.01 ppm to obtain a toluene solution of PTAA; then, the toluene solution of PTAA was evenly spin-coated on the ITO conductive glass anode in a nitrogen glove box. The parameters of the coater were a spin coating speed of 4000 rpm, a spin coating acceleration of 2000 rpm, and a spin coating time of 40 s. After the spin coating was completed, it was placed on a preheated hot plate and annealed at 100 ° C for 10 min, thereby obtaining a 30 nm PTAA anode buffer layer on the ITO conductive glass anode;

[0029] (3) First, prepare the tin-lead perovskite precursor solution by mixing DMF and DMSO at a volume ratio of 4:1 to obtain a mixed solvent; the raw materials FAI, PbI2, SnI2, CsI and GAI are mixed at a volume ratio of Cs 0.1 FA 0.85 GA 0.05 Pb 0.5 Sn 0.5 I3 was added to the mixed solvent in a stoichiometric ratio and stirred for 24 hours in a glove box filled with nitrogen and with a water and oxygen content of less than 0.01 PPm to obtain a perovskite precursor solution with a concentration of 1.5 mol / L. Then, in a glove box filled with nitrogen and with a water and oxygen content of less than 0.01 PPm, the parameters of the coater were set to a spin coating speed of 1000 rpm, a spin coating acceleration of 500 rpm, and a spin coating time of 10 s. 100 μL of DMF was added to the PTAA anode buffer layer for spin coating. After the spin coating was completed for 10 s, 70 μL of the perovskite precursor solution was spin coated on the PTAA anode buffer layer. The coater parameters were set to a spin coating time of 30 s, a spin coating speed of 4000 rpm, and a spin coating acceleration of 2000 rpm. When the spin coating time was left for 15 s, 300 μL of anti-solvent chlorobenzene was added. After the spin coating was completed, the device was transferred to a preheated hot stage and annealed at 100 ° C for 10 minutes to obtain a Cs with a thickness of 430 nm. 0.1 FA 0.85 GA 0.05 Pb 0.5 Sn 0.5 I3 tin-lead perovskite film;

[0030] (4) Using a multi-source organic vapor phase molecular deposition system at a pressure not higher than 7×10 -4 Pa, a 20 nm thick C layer was deposited on the SnPb perovskite film. 60 layer, then in C 60 A BCP layer with a thickness of 7 nm was then evaporated on the layer to obtain C 60 / BCP cathode buffer layer;

[0031] (5) Using a multi-source organic vapor phase molecular deposition system at a pressure not higher than 7×10-4 The tin-lead perovskite photodetector was prepared by evaporating Cu with a thickness of 80 nm on the BCP cathode buffer layer as cathode under the condition of Pa, C 60 The tin-lead perovskite photodetector was prepared by evaporating Cu with a thickness of 80 nm on the BCP cathode buffer layer as cathode under the condition of Pa, C

[0032] Example 1:

[0033] (1) The ITO conductive glass (20*15mm, area 300mm 2 ) was sequentially cleaned by ultrasonic cleaning with acetone for 30 min, ultrasonic cleaning with ethanol for 20 min, and ultrasonic cleaning with deionized water for 10 min, and then dried by nitrogen blowing to obtain dry and clean ITO conductive glass, and then treated by ultraviolet ozone for 30 min to obtain ITO conductive glass anode;

[0034] (2) 4 mg of PTAA was dissolved in 2 mL of toluene, and stirred for 24 h under the condition of nitrogen atmosphere and water oxygen content less than 0.01 PPM to obtain a toluene solution of PTAA; then the toluene solution of PTAA was uniformly spin-coated on the ITO conductive glass anode in a nitrogen glove box, and the parameters of the spin coater were as follows: spin-coating speed 4000 rpm, spin-coating acceleration 2000 rpm, spin-coating time 40 s; after spin-coating, the ITO conductive glass anode was placed on a preheated hot plate and annealed at 100°C for 10 min to obtain a 30 nm PTAA anode buffer layer on the ITO conductive glass anode;

[0035] (3) First, a tin-lead perovskite precursor solution was prepared. DMF and DMSO were mixed in a volume ratio of 4:1 to obtain a mixed solvent. The raw materials FAI, PbI2, SnI2, CsI, SrI2 and GAI were mixed in a molar ratio of Cs 0.1 FA 0.85 GA 0.05 Sr 0.002 Pb 0.499 Sn 0.499I3 stoichiometric ratio is added to the mixed solvent, and a perovskite precursor solution with a concentration of 1.5 mol / L is obtained by stirring in a glove box filled with nitrogen with a water oxygen content of less than 0.01 PPM for 24 h. Then, in a glove box filled with nitrogen with a water oxygen content of less than 0.01 PPM, the parameters of the spin coater are set as follows: the spin coating speed is 1000 rpm, the spin coating acceleration is 500 rpm, and the spin coating time is 10 s. 100 μL of DMF is spin coated on the PTAA anode buffer layer, and after spin coating for 10 s, 70 μL of perovskite precursor solution is spin coated on the PTAA anode buffer layer. The parameters of the spin coater are set as follows: the spin coating time is 25 s, the spin coating speed is 4000 rpm, and the spin coating acceleration is 2000 rpm. 250 μL of anti-solvent chlorobenzene is added at the remaining 15 s of the spin coating time. After spin coating, the device is transferred to a preheated hot plate and annealed at 100°C for 10 min to obtain a high-quality, well-formed 430 nm thick Cs 0.1 FA 0.85 GA 0.05 Sr 0.002 Pb 0.499 Sn 0.49 9I3 tin-lead perovskite film;

[0036] (4) A multi-source organic vapor phase molecular deposition system is used to evaporate a 20 nm thick C -4 layer on the tin-lead perovskite film under a pressure of not more than 7 x 10 60 Pa, and then a 7 nm thick BCP layer is evaporated on the C 60 layer to obtain a C 60 / BCP cathode buffer layer;

[0037] (5) A multi-source organic vapor phase molecular deposition system is used to evaporate 80 nm thick Cu as a cathode on the C -4 / BCP cathode buffer layer under a pressure of not more than 7 x 10 60 Pa, thereby preparing a tin-lead perovskite photodetector.

Claims

1. A method for preparing a tin-lead perovskite photodetector based on the introduction of guanidine ions and strontium ions, the steps of which are as follows: (1) The ITO conductive glass was ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water for 10 to 40 minutes, and then dried with nitrogen to obtain a clean ITO conductive glass, and then treated with ozone ultraviolet light for 30 to 40 minutes to obtain an ITO conductive glass anode; (2) In a nitrogen glove box or in an air environment, a toluene solution of PTAA is evenly spin-coated on an ITO conductive glass anode, and after annealing, a PTAA anode buffer layer with a thickness of 20 to 40 nm is obtained on the ITO conductive glass anode; (3) The raw materials FAI, PbI2, SnI2, GAI, SrI2 and CsI are prepared according to the tin-lead perovskite Cs 0.1 FA 0.85 GA 0.05 Sr 0.002 Pb 0.499 Sn 0.499 I3 is added to the mixed solvent in a stoichiometric ratio, and stirred for 20 to 24 hours in a glove box filled with nitrogen and with a water oxygen content of less than 0.01 ppm to obtain a perovskite precursor solution with a concentration of 1 to 1.5 mol / L; then, 90 to 120 μL of DMF is added dropwise to the PTAA anode buffer layer in a glove box filled with nitrogen at 800 to 1200 rpm for spin coating. After 10 to 15 seconds of spin coating, 60 to 90 μL of the perovskite precursor solution is spin coated on the PTAA anode buffer layer. The spin coating speed is set to 3500 to 4500 rpm, and the spin coating time is 25 to 40 seconds. When the spin coating time is remaining for 10 to 15 seconds, 250 to 350 μL of anti-solvent chlorobenzene is added dropwise; after the spin coating is completed, the device is transferred to a hot stage and annealed at 80 to 120°C for 10 to 15 minutes, thereby obtaining a 400 to 450 nm thick Cs on the PTAA anode buffer layer. 0.1 FA 0.85 GA 0.05 Sr 0.002 Pb 0.499 Sn 0.499 I3 tin-lead perovskite film; (4) At a pressure not higher than 7×10 -4 Pa vacuum, a C layer with a thickness of 20 to 40 nm was deposited on the Sn-Pb perovskite film. 60 layer, then in C 60 Then, a BCP layer with a thickness of 5 to 10 nm is evaporated on the layer to obtain C 60 / BCP cathode buffer layer; (5) At a pressure not higher than 7×10 -4 Pa, under C 60 A Cu cathode with a thickness of 80 to 90 nm is evaporated on the BCP cathode buffer layer, thereby preparing the tin-lead perovskite photodetector based on the introduction of guanidine ions and strontium ions according to the present invention.

2. The method for preparing a tin-lead perovskite photodetector based on the introduction of guanidine ions and strontium ions according to claim 1, characterized in that: In step (2), 4 to 8 mg of PTAA is dissolved in 2 to 4 mL of toluene, and the mixture is stirred for 20 to 24 hours under the conditions of nitrogen and water oxygen content below 0.01 ppm to obtain a toluene solution of PTAA.

3. The method for preparing a tin-lead perovskite photodetector based on the introduction of guanidine ions and strontium ions according to claim 1, characterized in that: The spin coating speed in step (2) is 3500-4500 rpm, the spin coating time is 35-45 s, and then annealing is carried out on a hot stage at 90-110° C. for 10-15 min.

4. The method for preparing a tin-lead perovskite photodetector based on the introduction of guanidine ions and strontium ions according to claim 1, wherein: In step (4), DMF and DMSO are mixed in a volume ratio of 4:1 to obtain a mixed solvent.

5. A tin-lead perovskite photodetector based on the introduction of guanidine ions and strontium ions, characterized by: The method is prepared by any one of claims 1 to 4.

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