A modification method to improve the light absorption of hybrid perovskite films and enhance their photoelectrochemical response

Abstract

The present invention relates to a modification method for improving the light absorption of a hybrid perovskite film and enhancing its photoelectrochemical response. The method comprises: applying a perovskite precursor droplet on conductive glass to obtain a hybrid perovskite film; thermally annealing the hybrid perovskite film; and plasma-treating the hybrid perovskite film after the thermal annealing to complete the modification of the hybrid perovskite film. The hybrid perovskite layer modified by plasma exhibits a porous, rough surface. The rough surface of the material can, on the one hand, cause incident light to be reflected and absorbed multiple times within the hybrid perovskite material. On the other hand, the rough surface provides a Brewster angle for specific incident light, thereby improving the material's absorptivity to light at that incident angle. This improves the light absorptivity of the hybrid perovskite material and further improves the photoelectric conversion efficiency of the perovskite layer.

Description

Technical Field

[0001] The present invention relates to a modification method for improving the light absorption of a hybrid perovskite film and enhancing its photoelectrochemical response, belonging to the technical field of light absorption film preparation. Background Art

[0002] With rapid economic development and continued population growth, global energy demand continues to rise. Currently, more than 80% of energy consumption comes from fossil fuels, causing serious environmental pollution and greenhouse effect.

[0003] In recent years, a new type of solar cell based on organometallic halide perovskites has seen rapid development. With an energy gap of approximately 1.5 eV and a high extinction coefficient, thin films a few hundred nanometers thick can fully absorb sunlight below 800 nm. This performance surpasses even the years of development of other types of cells, and in 2013, it was recognized by Science as one of the top ten scientific advances internationally. However, organometallic halide perovskites exhibit poor stability in humid environments and under direct sunlight, easily decomposing and causing cell efficiency to decline or even failure. Therefore, in addition to continuously improving conversion efficiency, efforts must also be made to enhance the stability of solar cells. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a method for modifying a hybrid perovskite film. Through this method, the hybrid perovskite film can improve its absorption of light and enhance its photoelectrochemical response through plasma treatment, thereby improving the photoelectric conversion ability of the perovskite film and improving the efficiency of perovskite solar cells.

[0005] To achieve the above objectives, the present invention provides a modification method for improving the light absorption of a hybrid perovskite film and enhancing its photoelectrochemical response, wherein the method comprises:

[0006] The perovskite precursor droplets were applied onto conductive glass to obtain a hybrid perovskite film;

[0007] thermally annealing the hybrid perovskite film;

[0008] The hybrid perovskite film that has been subjected to thermal annealing treatment is subjected to plasma treatment to complete the modification treatment of the hybrid perovskite film.

[0009] According to a specific embodiment of the present invention, preferably, the thermal annealing treatment is to perform a thermal annealing treatment on the hybrid perovskite film at 80-150°C for 0.5 to 2 hours; more preferably, the thermal annealing treatment is to perform a thermal annealing treatment on the hybrid perovskite film at 100°C for 1 hour.

[0010] According to a specific embodiment of the present invention, preferably, the plasma treatment is performed using a target material selected from the group consisting of nickel, aluminum, titanium, cobalt, chromium, tungsten and silicon.

[0011] According to a specific embodiment of the present invention, preferably, the plasma treatment time can be controlled to be 0.5 hours to 2 hours, more preferably 1 hour. The plasma treatment can be performed using different target materials.

[0012] According to a specific embodiment of the present invention, preferably, the perovskite is CH3NH3PbI3 perovskite.

[0013] According to a specific embodiment of the present invention, the method provided by the present invention may include the following specific steps (for example Figure 1 shown):

[0014] A CH3NH3PbI3 perovskite precursor droplet was applied onto conductive glass to obtain a hybrid perovskite film;

[0015] thermally annealing the hybrid perovskite film at 80-150° C. for 0.5 to 2 hours;

[0016] The hybrid perovskite film that has undergone thermal annealing is subjected to plasma treatment for 0.5 to 2 hours to complete the modification treatment of the hybrid perovskite film.

[0017] According to a specific embodiment of the present invention, preferably, the concentration of the CH3NH3PbI3 perovskite precursor solution is 0.1mM-1mM.

[0018] According to a specific embodiment of the present invention, the perovskite precursor solution can be obtained by placing CH3NH3I and PbI2 with a molar ratio of 1:1 into 1 ml of N,N-dimethylformamide (DMF) and stirring and dissolving them.

[0019] According to a specific embodiment of the present invention, the hybrid perovskite thin film can be prepared by a one-step solution method.

[0020] According to a specific embodiment of the present invention, preferably, the drop coating can be performed by using a pipette to transfer 200 mL of the perovskite precursor droplet onto the conductive glass.

[0021] According to a specific embodiment of the present invention, the conductive glass may be FTO conductive glass or ITO conductive glass.

[0022] The modification method provided by the present invention can give perovskite materials a porous and rough surface, significantly improving the perovskite material's light absorption and enhancing the efficiency of carrier generation in the device, ultimately effectively increasing the photoelectric conversion efficiency of perovskite photovoltaic devices. Furthermore, the optimized thin film preparation method of the present invention can be applied to other semiconductor thin film preparation fields.

[0023] The present invention also provides a hybrid perovskite film, which is prepared by the above method.

[0024] Generally speaking, in the field of photovoltaic devices, by applying different methods to increase the roughness of the light absorption layer in the photovoltaic device, the light absorption rate of the film can be improved. The optimized preparation method of the film in the present invention is to adopt the method of plasma immersion ion implantation, through which a perovskite film with high surface roughness and high light absorption rate is obtained. The hybrid perovskite layer modified by plasma presents a porous rough surface. On the one hand, the rough surface of the material can cause the incident light to be reflected and absorbed multiple times in the hybrid perovskite material. On the other hand, the rough surface provides a Brewster angle for specific incident light, thereby increasing the material's absorption rate of light at this incident angle, thereby increasing the absorption rate of the hybrid perovskite material to light, and further improving the photoelectric conversion efficiency of the perovskite layer. Under the premise of equal area, the increase in light absorption rate can enable the hybrid perovskite material to absorb more light energy, thereby improving the photoelectric response of the hybrid perovskite material. The modified hybrid perovskite layer can be effectively used in perovskite photovoltaic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic flow chart of the method for modifying the hybrid perovskite film provided by the present invention.

[0026] Figure 2 Schematic diagram of the photoelectrochemical cell test provided by the present invention; wherein 101 is the CH3NH3PbI3 working electrode, 102 is the Ag / AgNO3 reference electrode, 103 is the Pt counter electrode, 104 is the light source, and 105 is the electrochemical working cell.

[0027] Figure 3 Scanning electron microscope image of the hybrid perovskite layer of the control sample that was thermally annealed at 100°C for 1 hour and not plasma treated.

[0028] Figure 4 Scanning electron micrograph of the hybrid perovskite layer prepared after thermal annealing at 100°C for 1 hour and nickel plasma treatment for 1 hour.

[0029] Figure 5 Scanning electron microscopy image of the hybrid perovskite layer prepared after thermal annealing at 110°C for 0.5 hours and nickel plasma treatment for 0.5 hours

[0030] Figure 6 The UV-visible absorption spectra of the product of Example 1 and the comparative sample are shown.

[0031] Figure 7 The UV-visible absorption spectra of the product of Example 2 and the comparative sample are shown.

[0032] Figure 8 Photoelectrochemical response curve of perovskite treated with nickel plasma.

[0033] Figure 9 Photoelectrochemical response curve of perovskite treated with aluminum plasma. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for modifying a hybrid perovskite film, which includes the following specific steps:

[0037] First, use a wiping cloth to gently wipe away the dust and stubborn spots on the conductive glass. Then, ultrasonically clean the wiped conductive glass in acetone, deionized water, and anhydrous ethanol solvents for 20 minutes respectively. Finally, use nitrogen to blow dry the FTO conductive glass surface and set aside.

[0038] Weigh CH3NH3I and PbI2 at a molar ratio of 1:1 and place them in 1 ml of N,N-dimethylformamide. Stir for 1 hour to obtain a 1 mM CH3NH3PbI3 perovskite precursor solution for later use.

[0039] A CH3NH3PbI3 perovskite precursor droplet was applied onto conductive glass to obtain a hybrid perovskite film;

[0040] The hybrid perovskite film was thermally annealed at 100 °C for 1 h;

[0041] The hybrid perovskite film that has undergone thermal annealing is subjected to plasma treatment for 1 hour to complete the modification treatment of the hybrid perovskite film.

[0042] The material was characterized by UV-visible absorption spectroscopy and SEM to obtain the morphology and light absorption properties of the treated material, and its photoelectrochemical properties were studied through a photoelectrochemical cell system.

[0043] Figure 2Schematic diagram of the photoelectrochemical cell test used in the present invention to study the material properties; wherein 101 is the CH3NH3PbI3 working electrode, 102 is the Ag / AgNO3 reference electrode, 103 is the Pt counter electrode, 104 is the light source, and 105 is the electrochemical working cell. Figure 3 Scanning electron microscope image of the hybrid perovskite layer of the control sample that was thermally annealed at 100°C for 1 hour and not plasma treated. Figure 4 Scanning electron micrograph of the hybrid perovskite layer prepared after thermal annealing at 100°C for 1 hour and nickel plasma treatment for 1 hour.

[0044] Depend on Figure 3 、 Figure 4 It can be seen that after the perovskite film annealed at 100°C for 1 hour, it was treated with nickel plasma for 1 hour, and compared with the perovskite film that was not treated with nickel plasma. It was found that after 1 hour of nickel plasma modification, the surface roughness of the hybrid perovskite layer can be effectively improved, the reflection and absorption of light by the perovskite layer can be increased, and the photoelectric response performance of the hybrid perovskite material can be further improved.

[0045] Figure 6 These are the UV-visible absorption spectra of the modified hybrid perovskite film prepared in Example 1 and the comparative sample. Figure 8 The photoelectrochemical response curve of nickel plasma treated perovskite. Figure 6 、 Figure 8 It can be seen that compared with the control sample, the light absorption of the sample in Example 1 is significantly improved, which shows that the method in Example 1 improves the photoelectrochemical response of the sample.

[0046] Example 2

[0047] This embodiment provides a method for modifying a hybrid perovskite film, which includes the following specific steps:

[0048] First, use a wiping cloth to gently wipe away the dust and stubborn spots on the conductive glass. Then, ultrasonically clean the wiped conductive glass in acetone, deionized water, and anhydrous ethanol solvents for 20 minutes respectively. Finally, use nitrogen to blow dry the FTO conductive glass surface and set aside.

[0049] Weigh CH3NH3I and PbI2 at a molar ratio of 1:1 and place them in 1 ml of N,N-dimethylformamide. Stir for 1 hour to obtain a 1 mM CH3NH3PbI3 perovskite precursor solution for later use.

[0050] A CH3NH3PbI3 perovskite precursor droplet was applied onto conductive glass to obtain a hybrid perovskite film;

[0051] The hybrid perovskite film was thermally annealed at 110 °C for 1 h;

[0052] The hybrid perovskite film that has undergone thermal annealing is treated with nickel plasma for 0.5 hours to complete the modification of the hybrid perovskite film.

[0053] The material was characterized by UV-visible absorption spectroscopy and SEM to obtain the morphology and light absorption properties of the treated material, and its photoelectrochemical properties were studied through a photoelectrochemical cell system. Figure 5 Scanning electron micrograph of the hybrid perovskite layer prepared after thermal annealing at 110°C for 0.5 h and nickel plasma treatment for 0.5 h.

[0054] Depend on Figure 5 It can be seen that after the perovskite film annealed at 110°C for 1 hour and plasma treated for 0.5 hours, it was compared with the perovskite film that was not treated with plasma. It was found that after being modified by nickel plasma for 1 hour, the surface roughness of the hybrid perovskite layer can also be improved, the reflection and absorption of light by the perovskite layer can be increased, and the photoelectric response performance of the hybrid perovskite material can be further improved.

[0055] Figure 7 The UV-visible absorption spectra of the modified hybrid perovskite film prepared in Example 2 and the comparative sample are shown in FIG. Figure 7 It can be seen that compared with the control sample, the light absorption of the sample in Example 2 is also significantly improved.

[0056] Example 3

[0057] This embodiment provides a method for modifying a hybrid perovskite film, which includes the following specific steps:

[0058] First, use a wiping cloth to gently wipe away the dust and stubborn spots on the conductive glass. Then, ultrasonically clean the wiped conductive glass in acetone, deionized water, and anhydrous ethanol solvents for 20 minutes respectively. Finally, use nitrogen to blow dry the FTO conductive glass surface and set aside.

[0059] Weigh CH3NH3I and PbI2 with a molar ratio of 1:1 and place them into 1 ml of N,N-dimethylformamide solution. Stir for 1 hour to obtain a CH3NH3PbI3 perovskite precursor solution with a concentration of 1 mM for later use.

[0060] A CH3NH3PbI3 perovskite precursor droplet was applied on FTO conductive glass to obtain a hybrid perovskite film;

[0061] The hybrid perovskite film was thermally annealed at 100 °C for 1 h;

[0062] The thermally annealed hybrid perovskite film was treated with aluminum plasma for one hour to complete the modification. Its photoelectrochemical performance was studied using a photoelectrochemical cell system.

[0063] After annealing the perovskite film at 100°C for 1 hour and then treating it with aluminum plasma for 0.5 hours, the film was compared with the perovskite film that had not been treated with aluminum plasma. It was found that the photoelectric response performance of the material could also be improved after 1 hour of plasma modification.

[0064] Figure 9 The photoelectrochemical response curve of aluminum plasma treated perovskite. Figure 9 It can be seen that the photoelectric response curve of the sample treated with aluminum plasma has also been improved.

Claims

1. A modification method for improving the light absorption of a hybrid perovskite film and enhancing its photoelectrochemical response, wherein: The method includes: Applying a perovskite precursor droplet on a conductive glass to obtain a hybrid perovskite film, wherein the perovskite is CH3NH3PbI3 perovskite; thermally annealing the hybrid perovskite film; The hybrid perovskite film that has undergone thermal annealing is plasma treated with a nickel or aluminum target material, so that the hybrid perovskite film presents a porous and rough surface, thereby completing the modification treatment of the hybrid perovskite film.

2. The method according to claim 1, wherein The thermal annealing treatment is to perform a thermal annealing treatment on the hybrid perovskite film at 80-150° C. for 0.5 to 2 hours.

3. The method according to claim 1, wherein The plasma treatment time is 0.5 hours to 2 hours.

4. The method according to claim 1, wherein The method includes: A CH3NH3PbI3 perovskite precursor droplet was applied onto conductive glass to obtain a hybrid perovskite film; thermally annealing the hybrid perovskite film at 80-150° C. for 0.5 to 2 hours; The hybrid perovskite film that has undergone thermal annealing is subjected to plasma treatment for 0.5 to 2 hours to complete the modification treatment of the hybrid perovskite film.

5. The method according to claim 4, wherein The CH3NH3PbI3 perovskite precursor solution is obtained by placing CH3NH3I and PbI2 with a molar ratio of 1:1 into 1 ml of N,N-dimethylformamide and stirring to dissolve.

6. The method according to claim 5, wherein: The concentration of the CH3NH3PbI3 perovskite precursor solution is 0.1mM-1mM.

7. The method according to claim 1 or 5, wherein: The hybrid perovskite film is prepared by a one-step solution method.

8. The method according to claim 1 or 5, wherein: The drop coating is to use a pipette to transfer 200 mL of perovskite precursor droplets and coat them on the conductive glass.

9. The method according to any one of claims 1 to 8, wherein: The conductive glass is FTO conductive glass or ITO conductive glass.

10. A hybrid perovskite thin film prepared by the method according to any one of claims 1 to 9.

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