Light field regulation and control doping method for tin-based perovskite solar cell

Abstract

The invention provides a light field regulation and control doping method for a tin-based perovskite solar cell, and belongs to the technical field of solar cells, the light field regulation and control doping method comprises the steps that the tin-based perovskite solar cell is placed in a preset atmosphere for pretreatment, and the preset atmosphere comprises water and oxygen; transferring the pretreated tin-based perovskite solar cell to an inert gas environment; in an inert gas environment, placing the pretreated tin-based perovskite solar cell under a solar simulator for irradiation treatment; the tin-based perovskite solar cell comprises a perovskite light absorption layer and an electron transport layer located on the perovskite light absorption layer, the perovskite light absorption layer is a tin-based perovskite thin film, and the electron transport layer comprises at least one of fullerene, [6, 6]-phenyl C61 methyl butyrate and an indene-C60 double adduct. When the tin-based perovskite solar cell is processed by the method disclosed by the invention, the open-circuit voltage and the photoelectric conversion efficiency of the cell can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a light field regulation doping method for tin-based perovskite solar cells. Background Art

[0002] In recent years, perovskite semiconductor materials have attracted widespread attention due to their excellent optoelectronic properties. The photoelectric conversion efficiency of lead-based perovskite-based solar cells continues to improve, showing broad prospects for industrialization. However, the toxicity of the heavy metal lead limits the application of lead-based perovskite solar cells. Consequently, the next generation of low-toxicity, environmentally friendly tin-based perovskite solar cells has emerged.

[0003] However, the current photoelectric conversion efficiency of tin-based perovskite solar cells is generally much lower than that of lead-based batteries. One of the important factors is the large open-circuit voltage loss, which hinders further improvement of its photoelectric conversion efficiency. Summary of the Invention

[0004] In view of this, in order to at least partially solve the above-mentioned problems, the present invention provides a light field controlled doping method for tin-based perovskite solar cells to increase the open circuit voltage of tin-based perovskite solar cells.

[0005] According to an embodiment of one aspect of the present invention, a light field controlled doping method for a tin-based perovskite solar cell is provided, comprising: placing the tin-based perovskite solar cell in a preset atmosphere for pretreatment, the preset atmosphere comprising water and oxygen; transferring the pretreated tin-based perovskite solar cell to an inert gas environment; and placing the pretreated tin-based perovskite solar cell under a solar simulator for irradiation treatment in the inert gas environment; wherein the tin-based perovskite solar cell comprises a perovskite light absorption layer and an electron transport layer located on the perovskite light absorption layer, the perovskite light absorption layer comprising a tin-based perovskite film, and the electron transport layer comprising fullerene, [6,6]-phenyl C 61 Methyl butyrate and indene-C 60 At least one of the bisadducts.

[0006] According to an embodiment of the present invention, by subjecting tin-based perovskite solar cells to a light field-controlled doping process, the water and oxygen adsorbed by the tin-based perovskite solar cell during the pretreatment stage can promote the halogens in its perovskite crystal structure to move to the upper surface under the action of the light field and enter the electron transport layer. At the same time, the electron transfer between the halogen ions in the tin-based perovskite film and the fullerenes and their derivatives in the electron transport layer will produce an n-type doping effect on such electron transport layers, increasing their Fermi level position, thereby significantly improving the band matching of the tin-based perovskite solar cell. By controlling the specific atmosphere of the light exposure and related processes, the open circuit voltage of the tin-based perovskite solar cell can be significantly improved, thereby obtaining a tin-based perovskite solar cell device with higher photoelectric conversion efficiency and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. The drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0008] Figure 1 A flow chart of a light field controlled doping method for tin-based perovskite solar cells provided in an embodiment of the present invention;

[0009] Figure 2 A schematic cross-sectional view of a tin-based perovskite solar cell provided by an embodiment of the present invention;

[0010] Figure 3 A comparison chart of cell performance test results of tin-based perovskite solar cells provided by Comparative Examples 1 to 3 and Examples 1 to 3 of the present invention;

[0011] Figure 4A-4B Comparative diagrams of X-ray photoelectron spectra and iodine (I) content at the interface between the tin-based perovskite film and the electron transport layer provided in Comparative Example 1 and Example 1 of the present invention, respectively;

[0012] Figure 5 A comparison chart of the ultraviolet photoelectron spectra of the electron transport layer provided in Comparative Example 1 and Example 1 of the present invention;

[0013] Figure 6 This is a comparison chart of the cell performance test results of the tin-based perovskite solar cells provided in Comparative Example 2 and Examples 2, 4, and 5 of the present invention.

[0014] Description of reference numerals:

[0015] 1-substrate;

[0016] 2- bottom electrode;

[0017] 3-hole transport layer;

[0018] 4-Perovskite light absorption layer;

[0019] 5-electron transport layer;

[0020] 6-hole blocking layer;

[0021] 7- Top electrode. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. However, the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present invention thorough and complete and to fully convey the scope of the present invention to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for clarity, and like reference numerals denote like elements throughout.

[0023] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0024] The current photoelectric conversion efficiency of tin-based perovskite solar cells is generally much lower than that of lead-based perovskite solar cells. One of the main reasons for this is the large open-circuit voltage loss of tin-based perovskite solar cells. Due to the high valence band position of tin-based perovskites in the band structure, the carrier transport layer inherited from lead-based perovskite solar cells has not yet achieved a good energy band match with the tin-based perovskite layer, resulting in significant non-radiative recombination losses, limiting the open-circuit voltage of tin-based perovskite solar cells, and thus hindering further improvement of the photoelectric conversion efficiency of tin-based perovskite solar cells.

[0025] In view of this, the present invention provides a light field controlled doping method for tin-based perovskite solar cells to increase the open circuit voltage of tin-based perovskite solar cells.

[0026] Figure 1 Flowchart of the light field controlled doping method for tin-based perovskite solar cells provided in an embodiment of the present invention.

[0027] According to an exemplary embodiment of the present invention, the present invention provides a light field controlled doping method for tin-based perovskite solar cells, referring to Figure 1 As shown, it includes: operation S10 to operation S30.

[0028] In operation S10 , the tin-based perovskite solar cell is placed in a preset atmosphere for pretreatment, where the preset atmosphere includes water and oxygen.

[0029] In an embodiment of the present invention, the humidity range of the preset atmosphere is 15% RH ~ 50% RH, for example, it can be 15% RH, 20% RH, 30% RH, 40% RH, 50% RH, but is not limited to the values ​​listed above; if the humidity is too high, for example, exceeding 50% RH, the open-circuit voltage of the device will be greatly improved, but the yield of the device will decrease with the increase of humidity; if the humidity is too low, for example, less than 15% RH, the effect of improving the open-circuit voltage of the device is not significant; by controlling the humidity within the above-mentioned required range, better device performance improvement and higher yield can be achieved.

[0030] In embodiments of the present invention, the oxygen content range is 19.5% to 23.5%, for example, 19.5%, 20%, 21%, 22%, 23%, and 23.5%, but is not limited to these values. Devices treated in environments with excessively high oxygen content experience a significant increase in open-circuit voltage, but suffer from low yields and are susceptible to significant device damage. Devices treated in environments with excessively low oxygen content experience more stable performance, but the improvement in photoelectric conversion efficiency is less pronounced. By controlling the oxygen content within the aforementioned range, significant device performance improvements and a higher yield can be achieved.

[0031] In the embodiments of the present invention, the temperature range is 10°C to 20°C, for example, 10°C, 12°C, 15°C, 18°C, and 20°C, but is not limited to these values. Excessively high temperatures (e.g., greater than 20°C) can severely degrade the performance of tin-based perovskite solar cells and reduce their yield. By controlling the temperature within the aforementioned range, a higher yield can be achieved.

[0032] In some embodiments, the pretreatment duration can be 18 to 24 hours, for example, 18 hours, 20 hours, 21 hours, 22 hours, or 24 hours, but is not limited to these values. If the pretreatment duration is too long, the device will experience visible discoloration and degradation, and the device test performance will be significantly reduced. If the pretreatment duration is too short, the resulting device performance improvement will be significantly limited. By controlling the pretreatment duration within the above requirements, a better performance improvement can be achieved.

[0033] In some embodiments, the preset atmosphere is preferably a humidity of 20% rh, an oxygen content of 21%, a temperature of 20° C., and the treatment is performed for 24 hours.

[0034] In operation S20 , the pretreated tin-based perovskite solar cell is transferred to an inert gas environment.

[0035] In some embodiments, the inert gas environment has a water content of less than 0.3 ppm, an oxygen content of less than 10 ppm, and a temperature range of 10° C. to 25° C.

[0036] In an embodiment of the present invention, the inert gas environment preferably has a water content of 0.01 ppm, an oxygen content of 0.1 ppm, and a temperature of 20°C.

[0037] In operation S30 , the pretreated tin-based perovskite solar cell is placed under a solar simulator for irradiation treatment in an inert gas environment.

[0038] In an embodiment of the present invention, the light source of the solar simulator includes at least one of a xenon lamp, a carbon arc lamp, a tungsten lamp, a halogen lamp, and a light-emitting diode (LED).

[0039] In some embodiments, the irradiance of the light source of the solar simulator is 400 W / m 2 ~1500 W / m 2 ; For example, it can be 400 W / m 2 , 600 W / m 2 , 1000 W / m 2 , 1200 W / m 2 , 1500 W / m 2 , but not limited to the values ​​listed above. The irradiation intensity is too low (such as less than 400 W / m 2 ), the device's open-circuit voltage will not increase sufficiently; while excessive irradiation intensity will cause the device to experience reduced short-circuit current and loss of fill factor. By controlling the irradiation intensity within the above requirements, better open-circuit voltage, short-circuit current, and fill factor can be achieved.

[0040] In some embodiments, the irradiation duration is 20 min to 180 min, for example, 20 min, 50 min, 100 min, 150 min, or 180 min, but is not limited to the values ​​listed above.

[0041] In the embodiment of the present invention, the light source of the solar simulator is preferably a xenon lamp or LED, and the irradiation intensity of the light source is controlled to be 1000 W / m 2 , processed for 60 min.

[0042] In the related art, tin-based perovskite solar cells widely use fullerene electron transport layers inherited from lead-based perovskite solar cells. However, the conduction band of tin-based perovskites is much higher than that of conventional fullerene molecules (C 60) Fermi level, resulting in poor device band matching, open-circuit voltage loss, and reduced photoelectric conversion efficiency of the battery. The present invention achieves high-quality fullerene doping by performing light field-controlled doping on the prepared tin-based perovskite solar cell, inducing ion migration at the interface between the perovskite light absorption layer and the electron transport layer and producing a doping effect. This improves the Fermi level position of the electron transport layer, can improve the voltage loss problem caused by band mismatch, and can increase the steady-state operating open-circuit voltage of the tin-based perovskite solar cell, thereby facilitating improved photoelectric conversion efficiency.

[0043] In an embodiment of the present invention, the tin-based perovskite solar cell adsorbs water and oxygen in the pretreatment stage. The water and oxygen conditions cause vacancies in the tin-based perovskite film to form more tin ions and halogen ions in the lattice interstitial positions, which is conducive to promoting the halogen ions in the interstitial positions to move toward the upper surface (the side close to the electron transport layer) under the action of the light field and enter the electron transport layer, thereby realizing n-type doping of the electron transport layer.

[0044] Figure 2 A schematic cross-sectional view of a tin-based perovskite solar cell provided in an embodiment of the present invention.

[0045] According to an exemplary embodiment of the present invention, the present invention provides a tin-based perovskite solar cell treated by the above-mentioned light field control doping method, referring to Figure 2 As shown, the tin-based perovskite solar cell is located on a substrate 1, and the tin-based perovskite solar cell includes a bottom electrode 2, a hole transport layer 3, a perovskite light absorption layer 4, an electron transport layer 5, a hole blocking layer 6 and a top electrode 7 from bottom to top.

[0046] In some embodiments, the perovskite light absorbing layer 4 includes a tin-based perovskite film. The general formula of the tin-based perovskite is ABX3, wherein the A position includes an organic ammonium ion or an alkali metal ion, such as CH3NH3 + (Methylamine, MA + ), NH=CHNH3 + (methyl ether, FA + ) or Cs + ;B position is Sn 2+ ; X position includes a halogen ion, for example, including I - Br - 、Cl - At least one of - Br - 、Cl - The molar ratio of can be, for example, 1:0:0, 0.98:0.02:0, 0.98:0.015:0.005, but is not limited to the values ​​listed above.

[0047] In some embodiments, the electron transport layer 5 includes fullerene (C 60 ) and at least one of its derivatives. Preferably, the fullerene derivative includes [6,6]-phenyl C 61 Butyric acid methyl ester (PCBM) and indene-C 60 At least one of the bisadducts (ICBA).

[0048] In some embodiments, the hole blocking layer 6 includes bathocuproine (BCP) with a thickness of 5 nm to 8 nm.

[0049] The following schematically illustrates the light field controlled doping method designed for tin-based perovskite solar cells. It should be noted that this example is only a specific embodiment of the present invention and does not limit the scope of protection of the present invention.

[0050] Comparative Example 1

[0051] A tin-based perovskite solar cell is prepared. Specifically, the preparation process includes operations S1 to S6.

[0052] Operation S1: Substrate cleaning. Specifically, an indium tin oxide (ITO) transparent glass substrate was ultrasonically cleaned with glass cleaner, deionized water, acetone, and isopropyl alcohol for 20 minutes each, dried in an oven, and then cleaned with a UV ozone machine for 15 minutes.

[0053] Operation S2: Prepare a hole transport layer of poly (3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT:PSS). Specifically, PEDOT:PSS was spin-coated at 5000 rpm on an ITO transparent glass substrate in 10% RH air and annealed at 150°C for 15 minutes. After the PEDOT:PSS film cooled, the PEDOT:PSS-coated substrate was placed in a nitrogen-filled glove box.

[0054] Operation S3: Prepare a perovskite light absorption layer including a tin-based perovskite thin film. Specifically, prepare a 0.9M FASnI3 tin-based perovskite precursor solution, the solutes are formamidine hydroiodide (FAI), tin iodide (SnI2), and stannous fluoride (SnF2), the molar ratio of FAI, SnI2, and SnF2 is 1:1:0.1, and the volume ratio of the solvent is V DMF :V DMSO = 4:1 N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) mixed solution; the resulting solution was spin-coated on the hole transport layer at a spin-coating speed of 5000 r / min for 40 s. At the 20th s of the spin-coating time, 600 μL of chlorobenzene (CB) was added dropwise, and the film was annealed at 80 ° C for 10 min to obtain a FASnI3 perovskite film.

[0055] Operation S4: Preparation of electron transport layer C 60 Specifically, a 20 nm thick C 60 .

[0056] Operation S5: preparing a hole blocking layer BCP. Specifically, a thermal evaporation process is used to form a BCP with a thickness of 8 nm.

[0057] Operation S6: preparing a silver or copper electrode. Specifically, a thermal evaporation process is used to form a 100 nm thick silver or copper electrode.

[0058] The photoelectric performance of the tin-based perovskite solar cell obtained in Comparative Example 1 was tested, and the test results are shown in Table 1.

[0059] Comparative Example 2

[0060] The tin-based perovskite solar cell was prepared by the same method as in Comparative Example 1, except that 0.9 M EDA was prepared. 0.01 FA 0.98 SnI 2.98 Br 0.02 Tin-based perovskite precursor solution.

[0061] Specifically, the tin-based perovskite precursor solution includes formamidine hydroiodide (FAI), tin iodide (SnI2), stannous fluoride (SnF2), ethylenediamine dihydrobromide (EDABr2) and germanium diiodide (GeI2), the molar ratio of FAI, SnI2, SnF2, EDABr2, GeI2 is 0.98:1:0.1:0.01:0.05, and the volume ratio of solvent is V DMF :V DMSO = 4:1 DMF (N,N-dimethylformamide)-DMSO (dimethyl sulfoxide) mixed solution; the resulting solution was spin-coated on the hole transport layer at a spin-coating speed of 5000 r / min for 40 s. 600 μL of CB (chlorobenzene) was added dropwise at 15 s of the spin-coating time. The mixture was annealed at 80 °C for 20 min to obtain EDA. 0.01 FA 0.98 SnI 2.98 Br 0.02 Perovskite thin films.

[0062] The photoelectric performance of the tin-based perovskite solar cell obtained in Comparative Example 2 was tested, and the test results are shown in Table 1.

[0063] Comparative Example 3

[0064] The tin-based perovskite solar cell was prepared by the same method as in Comparative Example 1, except that 0.8 M PEA was prepared. 0.15 FA 0.85 SnI2.85 Br 0.15 Tin-based perovskite precursor solution and preparation of electron transport layer ICBA.

[0065] Specifically, 0.8 M PEA was prepared. 0.15 FA 0.85 SnI 2.85 Br 0.15 The tin-based perovskite precursor solution uses FAI, SnI2, SnF2, 2-(4-fluorophenyl)ethylamine hydrobromide (PEABr) and ammonium thiocyanate (NH4SCN), where the molar ratio of FAI, SnI2, SnF2, PEABr, and NH4SCN is 0.85:1:0.075:0.15:0.05, and the volume ratio of the solvent is V DMF :V DMSO = 4:1 DMF (N,N-dimethylformamide)-DMSO (dimethyl sulfoxide) mixed solution; the resulting solution was spin-coated on the hole transport layer at a spin-coating speed of 5000 r / min for 40 s. At the 26th s of the spin-coating time, 600 μL of Tol (toluene) was added dropwise. The mixture was annealed at 70°C for 10 min to obtain PEA. 0.15 FA 0.85 SnI 2.85 Br 0.15 Perovskite thin films.

[0066] The preparation of the electron transport layer ICBA includes: preparing a 20 mg / ml ICBA solution with CB (chlorobenzene) as the solvent; spin-coating the obtained solution on the perovskite light absorption layer at a spin coating speed of 1000 r / min for 30 s, and annealing at 70°C for 10 min to obtain the ICBA electron transport layer.

[0067] The photoelectric performance of the tin-based perovskite solar cell obtained in Comparative Example 3 was tested, and the test results are shown in Table 1.

[0068] Example 1

[0069] A tin-based perovskite solar cell is prepared by the same method as in Comparative Example 1, except that, after the preparation is completed, the prepared tin-based perovskite solar cell is subjected to light field regulation doping, and the light field regulation doping process includes operations S7 to S9.

[0070] Operation S7: Pretreatment process: The tin-based titanite solar cell prepared above was placed in an atmosphere of 20° C., 20% humidity, and 21% oxygen content for 24 hours.

[0071] Operation S8: Transfer process: The pre-treated tin-based titanite solar cell is transferred to a nitrogen glove box at 20° C., with a water content of 0.1 ppm and an oxygen content of 0.1 ppm for standby use.

[0072] Operation S9: Light field treatment process. The transferred tin-based titanite solar cell is subjected to a 1000W / m 2 , AM 1.5G (the standard spectrum on the earth's surface, defined as the reference spectrum for standard testing of solar energy conversion systems, the standard AM 1.5G irradiance is 1000 W / ㎡) LED simulates sunlight, ensuring that the light is vertically incident from the transparent electrode surface to the device surface for 120 minutes, and then shielded from light and left to stand for 5 minutes.

[0073] The photoelectric performance of the tin-based perovskite solar cell obtained in Example 1 was tested, and the test results are shown in Table 1.

[0074] Example 2

[0075] The prepared tin-based perovskite solar cell is processed in the same manner as in Comparative Example 2, except that, after the preparation is completed, the prepared tin-based perovskite solar cell is subjected to light field regulation doping, and the light field regulation doping process includes operations S7 to S9.

[0076] Operation S7: Pretreatment process: The tin-based titanite solar cell prepared above was placed in an atmosphere of 20° C., 20% humidity, and 21% oxygen content for 24 hours.

[0077] Operation S8: Transfer process: The pre-treated tin-based titanite solar cell is transferred to a nitrogen glove box at 20° C., with a water content of 0.1 ppm and an oxygen content of 0.1 ppm for standby use.

[0078] Operation S9: Light field treatment process. The transferred tin-based titanite solar cell is subjected to a 1000W / m 2 , AM 1.5G LED simulates sunlight, ensuring that the light is vertically incident from the transparent electrode surface to the device surface for 60 minutes, and then shielded from light and left to stand for 5 minutes.

[0079] The photoelectric performance of the tin-based perovskite solar cell obtained in Example 2 was tested, and the test results are shown in Table 1.

[0080] Example 3

[0081] The prepared tin-based perovskite solar cell is processed in the same manner as in Comparative Example 3, except that, after the preparation is completed, the prepared tin-based perovskite solar cell is subjected to light field regulation doping, and the light field regulation doping process includes operations S7 to S9.

[0082] Operation S7: Pretreatment process: The tin-based titanite solar cell prepared above was placed in an atmosphere of 20° C., 20% humidity, and 21% oxygen content for 24 hours.

[0083] Operation S8: Transfer process: The pre-treated tin-based titanite solar cell is transferred to a nitrogen glove box at 20° C., with a water content of 0.1 ppm and an oxygen content of 0.1 ppm for standby use.

[0084] Operation S9: Light field treatment process. The transferred tin-based titanite solar cell is subjected to a 1000W / m 2 , AM 1.5G LED simulates sunlight, ensuring that the light is incident vertically from the transparent electrode surface to the device surface for 20 minutes, and then shielded from light and left to stand for 5 minutes.

[0085] The photoelectric performance of the tin-based perovskite solar cell obtained in Example 3 was tested, and the test results are shown in Table 1.

[0086] Example 4

[0087] The tin-based perovskite solar cell was prepared by the same method as in Example 2, and the prepared tin-based perovskite solar cell was treated by the same light field regulation doping method as in Example 2, except that the humidity in the pretreatment process of the prepared tin-based perovskite solar cell was 40% rh and the oxygen content was 21%.

[0088] The photoelectric performance of the tin-based perovskite solar cell obtained in Example 4 was tested, and the test results are shown in Table 1.

[0089] Example 5

[0090] The tin-based perovskite solar cell was prepared by the same method as in Example 2, and the prepared tin-based perovskite solar cell was treated by the same light field regulation doping method as in Example 2, except that the humidity in the pretreatment process of the prepared tin-based perovskite solar cell was 30% rh and the oxygen content was 21%.

[0091] The photoelectric performance of the tin-based perovskite solar cell obtained in Example 5 was tested, and the test results are shown in Table 1.

[0092] Example 6

[0093] The tin-based perovskite solar cell was prepared by the same method as in Example 2, and the prepared tin-based perovskite solar cell was treated by the same light field regulation doping method as in Example 2, except that the humidity in the pretreatment process of the prepared tin-based perovskite solar cell was 10% rh and the oxygen content was 21%.

[0094] The photoelectric performance of the tin-based perovskite solar cell obtained in Example 6 was tested, and the test results are shown in Table 1.

[0095] Table 1

[0096]

[0097] Figure 3 A comparison chart of the cell performance test results of the tin-based perovskite solar cells provided in Comparative Examples 1 to 3 and Examples 1 to 3 of the present invention is shown. In this test, a digital source meter Keithley 2400 was used to scan the photocurrent density-voltage curves of the tin-based perovskite solar cells obtained in Comparative Examples 1 to 3 and Examples 1 to 3 of the present invention, respectively.

[0098] refer to Figure 3 As shown, the photoelectric conversion efficiency of the tin-based perovskite solar cells in the embodiments is significantly higher than that of the tin-based perovskite solar cells in the corresponding comparative examples. Specifically, the photoelectric conversion efficiency of the tin-based perovskite solar cell in Example 1 reached 6.92%, and the open-circuit voltage was up to 0.48 V. In comparison, the photoelectric conversion efficiency of the tin-based perovskite solar cell in Comparative Example 1 was only 5.74%, and the open-circuit voltage was only 0.4 V. The photoelectric conversion efficiency of the tin-based perovskite solar cell in Example 2 reached 14.91%, and the open-circuit voltage was up to 0.8 V. In comparison, the photoelectric conversion efficiency of the tin-based perovskite solar cell in Comparative Example 2 was only 11.08%, and the open-circuit voltage was only 0.59 V. The photoelectric conversion efficiency of the tin-based perovskite solar cell in Example 3 reached 14.25%, and the open-circuit voltage was up to 0.89 V. In comparison, the photoelectric conversion efficiency of the tin-based perovskite solar cell in Comparative Example 3 was only 12.07%, and the open-circuit voltage was only 0.81 V.

[0099] Figure 4A-4B Comparison diagrams of X-ray photoelectron spectra and I element content at the interface between the tin-based perovskite film and the electron transport layer provided in Comparative Example 1 and Example 1 of the present invention, respectively.

[0100] refer to Figure 4A 、 Figure 4B As shown in the figure, according to the comparison of the peak shape and peak area of ​​the I element in the synchrotron radiation in situ X-ray photoelectron spectroscopy reaction, it can be judged that after the light field control doping treatment, a new characteristic peak I 3-This characteristic peak indicates the occurrence of a redox reaction, indicating the presence of electron transfer at the interface of the tin-based perovskite film after light field modulation doping. On the other hand, the increase in the I element spectrum peak area after light field modulation doping indicates that the I element moves closer to the electron transport layer on the upper surface after light field modulation doping. The I element content at the interface between the tin-based perovskite film and the electron transport layer increases, resulting in a significant signal enhancement.

[0101] Figure 5 This is a comparison chart of the ultraviolet photoelectron spectra of the electron transport layer provided by Comparative Example 1 and Example 1 of the present invention.

[0102] like Figure 5 As shown, the ultraviolet photoelectron spectrum of Example 1 shows C 60 The surface binding energy shifted by 0.13 eV after light field modulation doping treatment, indicating that the energy difference between the Fermi level and the valence band increased by 0.13 eV, which directly explains the C 60 The electron transport layer is further n-doped after treatment, which produces a band-matching effect. Figure 4A 、 Figure 4B The conclusions and related research support that halogen ions such as iodine (I) can react with C 60 A type of fullerene material is n-doped. Leveraging this mechanism, the present invention's light-field-controlled doping method for tin-based perovskite solar cells utilizes this mechanism. By targeting the appropriate amount of water and oxygen adsorbed on the device interface during the pretreatment phase, the method promotes the migration of halogens within the perovskite crystal structure toward the upper surface and into the electron transport layer under the action of light. Simultaneously, electron transfer between the halogen ions and the fullerene and its derivatives produces an n-type doping effect on the electron transport layer, raising its Fermi level and significantly improving the bandgap matching of the tin-based perovskite solar cell. Ultimately, by controlling the specific illumination atmosphere and related processes, the open-circuit voltage of the tin-based perovskite solar cell is significantly increased, resulting in a solar cell device with higher photoelectric conversion efficiency and stability.

[0103] Figure 6 This is a comparison chart of the cell performance test results of the tin-based perovskite solar cells provided in Comparative Example 2 and Examples 2, 4, and 5 of the present invention.

[0104] refer to Figure 6As shown in Table 1, the photoelectric conversion efficiency and open-circuit voltage of the tin-based perovskite solar cell of Example 1 are significantly higher than those of the tin-based perovskite solar cell of Comparative Example 1; the photoelectric conversion efficiency and open-circuit voltage of the tin-based perovskite solar cell of Example 2 are significantly higher than those of the tin-based perovskite solar cell of Comparative Example 2; the photoelectric conversion efficiency and open-circuit voltage of the tin-based perovskite solar cell of Example 3 are significantly higher than those of the tin-based perovskite solar cell of Comparative Example 3.

[0105] Compared to Comparative Example 2, which did not undergo light field regulation doping treatment, Examples 2 and 4 to 6 all performed light field regulation doping treatment on the prepared tin-based perovskite solar cells, so that the open circuit voltage of the obtained tin-based perovskite solar cells was significantly improved. By comparing Example 2 and Example 4 to Example 6, it can be seen that the main difference lies in the different water and oxygen environments used in the pretreatment process. Example 2 and Example 5 have better battery performance than Example 4 and Example 6. This is because the excessively high water and oxygen content in Example 4 will oxidize the tin-based perovskite solar cell and reduce battery performance, while the excessively low water and oxygen content in Example 6 has no significant effect on improving battery performance. It can be seen from this that the humidity range of the preset atmosphere in the pretreatment process is 15% rh ~50% rh and the oxygen content range is 19.5% ~ 23.5%, which is more preferred.

[0106] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A light field control doping method for a tin-based perovskite solar cell, wherein the tin-based perovskite solar cell comprises a perovskite light absorbing layer and an electron transport layer located on the perovskite light absorbing layer, wherein the perovskite light absorbing layer comprises halogen ions, characterized in that: The light field controlled doping method comprises: Placing the tin-based perovskite solar cell in a preset atmosphere for pretreatment, wherein the preset atmosphere includes water and oxygen, so that the tin-based perovskite solar cell absorbs water and oxygen to convert the halogen ions into freely mobile halogen ions; and placing the pretreated tin-based perovskite solar cell under a solar simulator for irradiation treatment in an inert gas environment to migrate the halogen ions in the perovskite light absorption layer to the electron transport layer, thereby achieving halogen ion doping of the electron transport layer; Wherein, the perovskite light absorption layer is a tin-based perovskite film, and the electron transport layer includes fullerene, [6,6]-phenyl C 61 Methyl butyrate and indene-C 60 at least one of the bisadducts; The humidity range of the preset atmosphere is 20% rh~30% rh, the oxygen content range is 19.5%~23.5%, and the temperature range is 10℃~20℃.

2. The light field controlled doping method according to claim 1, characterized in that: The duration of the pretreatment is 18 h to 24 h.

3. The light field controlled doping method according to claim 1, characterized in that: The water content of the inert gas environment is less than 0.3 ppm, the oxygen content is less than 10 ppm, and the temperature range is 10°C to 25°C.

4. The light field controlled doping method according to claim 1, characterized in that: The light source of the solar simulator includes at least one of a xenon lamp, a carbon arc lamp, a tungsten lamp, a halogen lamp and a light emitting diode.

5. The light field controlled doping method according to claim 1, characterized in that: The irradiance of the solar simulator light source is 400 W / m 2 ~1500 W / m 2 .

6. The light field controlled doping method according to claim 1, characterized in that: The light source irradiation time of the solar simulator is 20 min to 180 min.

7. The light field controlled doping method according to claim 1, characterized in that: The tin-based perovskite solar cell comprises, from bottom to top, a bottom electrode, a hole transport layer, the perovskite light absorption layer, the electron transport layer, a hole blocking layer and a top electrode.

8. The light field controlled doping method according to claim 1, characterized in that: The general formula of the tin-based perovskite film is ABX3, wherein the X position includes I - Br - 、Cl - At least one of .

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