Preparation method of chalcogen atom cluster and application thereof in solar cell

Abstract

The present application belongs to the technical field of solar cells, and relates to a preparation method of oxygen atom clusters and application of the oxygen atom clusters in solar cells. The present application utilizes liquid phase pulse irradiation technology to convert oxygen atom clusters into oxygen atom clusters in a specific target solution by laser irradiation of a target solution containing oxygen atom materials under a nitrogen atmosphere. Further, a perovskite film doped with oxygen atom elements is constructed, thereby solving the problem of introducing pseudo-halogen ion elements in X position when preparing a doped perovskite material in the prior art. Further, the perovskite film prepared based on the oxygen atom clusters has greatly improved light stability, high crystalline quality and reduced defect density, and is suitable for use in preparation of a PSC or a PSC solar cell.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology and relates to a method for preparing oxalic group atomic clusters and their application in solar cells. Background Technology

[0002] Photovoltaic technology can maximize the utilization of solar energy resources, helping to build a low-carbon, clean, and efficient modern energy system. Compared with the current mainstream silicon-based solar cells, perovskite solar cells, as third-generation photovoltaic devices, have significant advantages such as low manufacturing cost and high photoelectric conversion efficiency, making them an important technological direction for promoting the high-quality development of the photovoltaic industry.

[0003] In nature, perovskite crystals typically exist in the ABX3 form, where A, B, and X are a monovalent cation, a divalent metal cation, and a monovalent halide anion, respectively. This structure shares a BX6 octahedron, with the A-site cation located within the octahedron. Furthermore, the A-site cation is generally methylamine (CH3NH3). + (MA) + ), formamidin CH(NH2)2 + (FA) + Organic amine cations or Cs + 、Rb + Na + K + Alkali metal cations; the B-site is a divalent metal cation, such as Pb. 2+ and Sn 2+ Ions; X represents a halide anion, such as I. − ,Br − or Cl − Ions. Given the flexibility and variability of A, B, and X-site ions in the perovskite structure, the band gap of perovskite can be precisely controlled within the range of 1.2 eV to 2.5 eV by changing the types and proportions of A, B, and X-site ions. This characteristic allows it to adapt to the application requirements of different scenarios, making it one of the current research hotspots in the field of perovskite solar cell materials.

[0004] However, the flexible and varied structure of perovskites also makes it easy for ions to migrate within the perovskite, resulting in instability in perovskite materials and devices, thus restricting the industrial application of perovskite materials. Specifically, the weak bonding between B-site cations and X-site anions allows X-site anions to easily migrate within the perovskite active layer, leaving the active layer and entering other battery structures. For example, iodine ions migrating to the Ag metal electrode can easily form AgI (Science, 2025, 387(6730), 186-19), blocking the extraction and transport of photogenerated holes and reducing device performance. In addition, in wide-bandgap perovskite materials, changes in the halide ion ratio lead to deformation of the octahedral framework, an increase in intrinsic defects in the film, and uneven initial crystallization, making ion migration more severe and ultimately leading to perovskite phase separation (Science, 2022, 378(6621), 747-754). Therefore, in order to solve the stability problem caused by the above-mentioned ion migration, researchers have found through extensive research that micro-doping can suppress ion migration and improve stability by increasing the valence state, introducing lattice distortion, and changing residual stress.

[0005] In the aforementioned doping research, researchers further discovered that X-site anions are not limited to halide ions, but can be broadly defined as anions with a negative monovalent, polyatomic anions, or mixtures of both, such as formates, azides, and cyanates. Taking pseudohalogen ions as an example, X-site doping can increase the halogen vacancy formation energy in perovskites (Nature Energy, 2024, 9(5), 592-601), alleviating ion migration problems to some extent. Although pseudohalogen ions have certain advantages in X-site doping modification of perovskite materials, introducing pseudohalogen ions at the X-site into perovskite materials still faces problems such as limited selectivity, high difficulty in synthesizing perovskites, and easy reaction with B-site ions, leading to a decline in the performance of perovskite materials.

[0006] Therefore, how to solve the above problems has become a key technological bottleneck that urgently needs to be overcome in the field of perovskite materials. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing oxalic clusters and their application in solar cells, thereby solving the problem of introducing pseudo-halogen ions at the X-site when preparing doped perovskite materials using existing technologies.

[0008] The technical concept of this invention is to propose a method for preparing oxalate clusters based on liquid-phase pulsed irradiation technology and to use these oxalate clusters in the regulation of perovskite doping to improve the performance of perovskite solar cells. Specifically, by using a laser-induced transient high-temperature and high-pressure environment, bond breaking and rapid recombination of the inorganic material crystal structure are achieved, thereby obtaining a cluster structure with controllable size and high surface activity. This is the first time that the controllable preparation of oxalate clusters (< 1 nm) has been realized. This invention extends the size scale of oxalate clusters to the sub-nanometer range through liquid-phase pulsed irradiation technology. The significant reduction in size results in a higher proportion of surface atoms and more active surface states, thus endowing them with excellent physicochemical properties. Furthermore, the prepared oxalate clusters are introduced into the perovskite precursor to form an oxalate-doped perovskite thin film. The oxalate clusters can interact with Pb... 2+ Strong coordination interactions are formed, participating in the local reconstruction of Pb-X octahedrons and creating halogen-like sites in the lattice, thereby reducing halogen vacancy defects and increasing the ion migration barrier. Simultaneously, the tuning of the Fermi level by chalcogen group clusters helps optimize carrier transport and reduce nonradiative recombination, resulting in chalcogen-doped perovskite films exhibiting high crystallinity, reduced defect density, and good photostability; they are suitable for preparing... Type structure, Perovskite solar cells with a morphological structure.

[0009] To achieve the above-mentioned objectives and concepts, the technical solution adopted by this invention is as follows:

[0010] A method for preparing a chalcogenide cluster includes the following steps:

[0011] S1. Based on liquid-phase pulsed irradiation technology, laser irradiation is performed simultaneously with ultrasonic treatment of a target solution containing oxalic materials under a nitrogen atmosphere;

[0012] S2. The target solution containing oxalic materials after S1 treatment is further frozen with liquid nitrogen, then irradiated with laser and then thawed.

[0013] S3. Repeat step S2 multiple times to obtain oxalic atom clusters coordinated with the target solution.

[0014] Further specified, the oxalic material is sulfur powder, selenium powder or tellurium powder; the target solution is dimethyl sulfoxide, ethanol or isopropanol; the ratio of oxalic material to target solution is 0.015 mg: 10 mL.

[0015] Preferably, when the target solution is dimethyl sulfoxide (DMSO), which is the solution required for preparing the perovskite precursor, the perovskite can be prepared using a one-step antisolvent method.

[0016] Preferably, when the target solution is ethanol or isopropanol (IPA), the target solution is the solvent required for the second step of the two-step sequential solution method, and perovskite is prepared by the two-step method of vapor deposition solution.

[0017] Further specified, the purity of the oxalic material is 99.99%, and the particle size is 200 mesh.

[0018] Further specifying, in steps S1 and S2, the laser irradiation conditions are as follows: laser wavelength of 1064 nm, frequency of 10 Hz, pulse width of 8 ns, beam diameter of 8 mm; intensity of 600 J / pulse cm. 2 -1.2 J / pulse cm 2 The time is 3 min-5 min; the intensity of laser irradiation in step S1 is lower than the intensity of laser irradiation in step S2.

[0019] A perovskite thin film doped with chalcogenide elements is disclosed. The perovskite thin film is formed by introducing an atomic cluster solution into a perovskite precursor solution and depositing it via a one-step spin-coating or a two-step sequential method. The atomic cluster solution is prepared by either of the aforementioned methods. Preferably, the one-step spin-coating is a one-step anti-solvent method for preparing perovskite; the two-step sequential method is a two-step method using a vapor deposition solution to prepare perovskite.

[0020] Further specified, the concentration of the perovskite precursor solution is 1.8 mmol / mL; the solution used in the perovskite precursor solution is N,N-dimethylformamide; the volume ratio of N,N-dimethylformamide to the cluster solution is 4:1.

[0021] The present invention also provides the application of oxalite-doped perovskite thin films in solar cells.

[0022] Preferably, the method for preparing a solar cell is as follows:

[0023] S1. Prepare the substrate for perovskite deposition; the substrate is an incomplete perovskite solar cell with a conductive substrate and a charge transport layer (electron transport layer / hole transport layer);

[0024] S2. Apply the cluster solution to the perovskite deposition process to obtain a perovskite film deposited on the substrate, thus obtaining a perovskite absorber layer.

[0025] S3. Based on the perovskite thin film obtained in step S2, continue to deposit a charge transport layer (electron transport layer / hole transport layer) and deposit a back electrode to form a perovskite solar cell, i.e., a solar cell.

[0026] Further specifying, the solar cell is Type structure; The structure is arranged in the following order: conductive substrate, electron transport layer, perovskite absorber layer, hole transport layer and back electrode.

[0027] The perovskite absorber layer is a perovskite thin film doped with group A elements, and the structure of the perovskite absorber layer is A. a B b X c A mixture of one or more of the following, wherein A is CH3NH3 + HC(NH2)2 + Cs + or Rb + B is Pb 2+ or Sn 2+ X represents halide ions and oxalic elements.

[0028] Further specifying, the solar cell is Type structure; The structure is arranged in the following order: conductive substrate, hole transport layer, perovskite absorber layer, electron transport layer and back electrode.

[0029] The perovskite absorber layer is a perovskite thin film doped with group A elements, and the structure of the perovskite absorber layer is A. a B b X c A mixture of one or more of the following, wherein A is CH3NH3 + HC(NH2)2 + Cs + or Rb + B is Pb 2+ or Sn 2+ X represents halide ions and oxalic elements.

[0030] The thickness of the perovskite absorber layer is further specified to be 200 nm-900 nm.

[0031] The electron transport layer is made of n-type inorganic semiconductor material or organic semiconductor material, and the thickness of the electron transport layer is 10 nm-120 nm.

[0032] Preferably, the material of the electron transport layer is C. 60 PCBM ([6,6]-phenyl-C 61 One or more of methyl butyrate and SnO2 (tin dioxide);

[0033] The hole transport layer is made of a p-type semiconductor, and the thickness of the hole transport layer is 10 nm-300 nm.

[0034] Preferably, the hole transport layer is made of NiO. XOne or more of PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), Me-4PACz (methyl-4-phosphonic carbazole) and Spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene);

[0035] The back electrode is a metal electrode with a thickness of 100 nm, preferably an ITO electrode.

[0036] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0037] 1. This invention utilizes liquid-phase pulsed irradiation technology to prepare chalcogenide clusters with good dispersion, small size, and uniformity, such as... Figure 1 As shown. Specifically, liquid-phase pulsed irradiation technology utilizes high-energy unfocused lasers to bombard target oxogroup materials in a liquid medium, transforming them into atomic clusters or other plasmas under high-energy and extreme conditions, while simultaneously rapidly cooling them to form metastable atomic clusters coordinated with the target solution. The principle of liquid-phase pulsed irradiation technology in this invention is: based on the absorption of different wavelengths by the target oxogroup material, by adjusting the laser wavelength, laser energy, and irradiation time, the oxogroup material is transformed into nanocrystals or atomic clusters, thereby obtaining oxogroup atomic clusters. This invention, using liquid-phase pulsed irradiation technology under specific conditions, has for the first time achieved the controllable preparation of oxogroup atomic cluster (< 1 nm) nanocrystals in the sub-nanometer range. Compared to existing nanocrystals with sizes of 3 nm-5 nm, the significant reduction in the size of the nanomaterials in this invention gives the oxogroup atomic clusters a higher proportion of surface atoms and more active surface states, thus endowing them with physicochemical properties different from traditional nanocrystals. Furthermore, by introducing oxogroup atomic clusters into perovskite materials, this solves the problem of using pseudohalogen ions when doping existing perovskite materials, improving the performance of perovskite materials.

[0038] 2. In the preparation of oxogroup atom clusters using liquid-phase pulsed irradiation technology, the target material (oxogroup material) is placed in the target solution and dispersed by ultrasound; pulsed irradiation is then performed under a nitrogen atmosphere. This process effectively avoids the generation of other substances and pollution, and the prepared oxogroup atom clusters are free of undesirable ligands, further preventing the introduction of undesirable ligands into the perovskite material and affecting its performance.

[0039] 3. The method for preparing oxalate clusters in this invention is simple and quick. Under laser irradiation at a wavelength of 1064 nm, by controlling the intensity and time of irradiation, the complex reaction processes and the presence of various ligands required in chemical cluster preparation methods are eliminated. Furthermore, due to the diverse selection of liquid media during laser irradiation, clusters prepared using different solutions can be used in different perovskite deposition methods, thereby further broadening the range of oxalate-doped perovskites. In addition, perovskite thin films are also suitable for preparing… type or Perovskite solar cells have provided a wide range of applications for perovskite photovoltaic devices.

[0040] 4. This invention introduces the prepared oxalate clusters into the perovskite precursor system and systematically studies their regulatory effect on perovskite and its underlying mechanism. Results show that the wide-bandgap perovskite thin film prepared by this invention exhibits significantly improved light-induced stability, with no phase separation occurring after 14 days of illumination. Furthermore, test results indicate that the wide-bandgap perovskite thin film doped with oxalate elements has high crystallinity and reduced defect density, and its surface cell and Fermi level also show changes. The prepared wide-bandgap perovskite solar cell achieves a photoelectric conversion efficiency as high as 23.17%. This invention is the first to apply oxalate clusters prepared using liquid-phase pulsed irradiation technology to wide-bandgap perovskite photovoltaic devices, achieving a synergistic improvement in device performance and light-induced stability.

[0041] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0042] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0043] Figure 1 This is a schematic diagram illustrating the preparation of chalcogenide clusters using liquid-phase pulsed irradiation technology in an embodiment of the present invention.

[0044] Figure 2 This is a morphological image of the Se atom cluster prepared in Example 1 of the present invention;

[0045] Figure 3 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the Se atom cluster prepared in Example 1 of this invention.

[0046] Figure 4 The image shows a time-of-flight secondary mass spectrometry (TOF-SIMS) image of the Se cluster-doped perovskite thin film prepared in Example 2 of this invention.

[0047] Figure 5The images show the X-ray diffraction (XRD) patterns of the Se cluster-doped perovskite film (Se) and the undoped perovskite film (Control) of this invention, with the right side being an enlarged view of a portion of the left side.

[0048] Figure 6 The images show the fluorescence peak positions of the Se cluster-doped perovskite film (1.68 eV - Se) and the undoped perovskite film (1.68 eV - Control) of this invention.

[0049] Figure 7 The images show the time-resolved photoluminescence (TRPL) spectra of the Se cluster-doped perovskite film (Se) and the undoped perovskite film (Control) of this invention.

[0050] Figure 8 The photoluminescence (PL) spectra of the Se cluster-doped perovskite film (1.68 eV - Se) and the undoped perovskite film (1.68 eV - Control) as a function of illumination time are shown.

[0051] Figure 9 The images show the surface and cross-sectional morphology of the Se cluster-doped perovskite film (1.68 eV - Se Aged) and the undoped perovskite film (1.68 eV - Control Aged) after illumination.

[0052] Figure 10 Photoluminescence (PL) spectra of the Se cluster-doped perovskite film (1.78 eV - Se) and the undoped perovskite film (1.78 eV - Control) prepared in Example 3 of this invention as a function of illumination time;

[0053] Figure 11 The graphs show the efficiency curves of the Se cluster-doped perovskite solar cell (Se) and the undoped perovskite solar cell (Control) of this invention. Detailed Implementation

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0056] Example 1

[0057] In this embodiment, the preparation method of oxogroup atom clusters is as follows: under a nitrogen atmosphere, based on liquid phase pulse irradiation technology, a target solution containing oxogroup materials is irradiated with a laser, that is, a non-focused pulsed laser beam is used to bombard the oxogroup materials in the target solution to convert them into oxogroup atom clusters, and then the solution is cooled and thawed; the above process is repeated multiple times to obtain oxogroup atom clusters coordinated with the target solvent.

[0058] Preferably, the oxalic material is selenium (Se) powder, specifically commercially available Se solid powder with a purity of 99.99% and a mesh size of 200; the target solution is dimethyl sulfoxide (DMSO).

[0059] In this embodiment, the specific preparation of the oxalic group cluster is as follows:

[0060] S1. Dissolve 0.015 mg Se powder in 10 mL DMSO and sonicate at 0℃ for 10 min to obtain a DMSO solution containing Se, which is the target solution containing oxalic materials.

[0061] S2. Transfer the ultrasonically dispersed DMSO solution containing Se to a liquid-phase pulsed irradiation system, introduce nitrogen gas, and simultaneously perform ultrasonic treatment at -20 °C. Simultaneously, select a laser with a wavelength of 1064 nm (frequency 10 Hz, pulse width 8 ns, beam diameter 8 mm) and adjust the laser irradiation intensity to 600 mJ / pulse cm⁻¹. 2 Irradiate for 5 minutes;

[0062] S3. Select a laser with a wavelength of 1064 nm, a frequency of 10 Hz, a pulse width of 8 ns, and a beam diameter of 8 mm, and adjust the laser irradiation intensity to 1.2 J / pulse cm. 2 The liquid (the target solution containing oxalic materials after irradiation in step S2) was frozen using liquid nitrogen and irradiated for 5 minutes. After thawing at room temperature, the process was repeated twice to obtain oxalic atom clusters coordinated with the target solution, which were denoted as a cluster solution.

[0063] During the above preparation process, at 600 mJ / pulse cm 2 During irradiation, because the ultrasonic treatment is performed at -20 ℃, the operating temperature is low, and the laser irradiation intensity and laser energy are also low, therefore cooling is not required and the process does not need to be repeated; when at 1.2 J / pulse cm 2 During irradiation, the intensity of laser irradiation increases, requiring repeated freezing-irradiation-thawing operations. This facilitates the coordination of oxalite materials with the target solution to generate oxalite clusters.

[0064] In this embodiment, the atomic cluster solution obtained from the above process is dropped onto a copper grid and dried. The sample is then observed using a double-corrected spherical aberration electron microscope. Figure 2 As shown. Different contrast colors can be observed in the dark, with predominantly white dot clusters confirming the presence of atomic clusters in the solution. Further analysis of the obtained atomic cluster solution using synchronous absorption spectroscopy confirmed that the laser-treated solution mainly contains three substances: selenium dioxide, selenium powder, and Se atomic clusters coordinated with DMSO. Selenium dioxide and selenium powder can be removed during the perovskite preparation process through filtration and other methods. Further, the atomic cluster solution obtained in the above process was drop-coated onto a glass substrate and subjected to X-ray photoelectron spectroscopy (XPS) testing along with untreated selenium powder, as shown... Figure 3 As shown, the results indicate that the binding energy of the Se atom clusters decreased after laser treatment, and they transformed from a powdery elemental state to a metastable state in solution. This demonstrates that this embodiment successfully prepared sub-nanometer-scale chalcogenide clusters.

[0065] It should be noted that in Example 1 above, the oxalic material can be replaced with sulfur (S) powder or tellurium (Te) powder. The target solution can be replaced with ethanol or isopropanol; step S3 is repeated 3-5 times; the laser irradiation intensity is 600 J / pulsecm. 2 -1.2 J / pulse cm 2 Internal changes; and the intensity of laser irradiation in step S2 is lower than that in step S3. After replacement, sub-nanometer (< 1 nm) oxalate clusters can be prepared, and the prepared oxalate clusters have a higher proportion of surface atoms and more active surface states.

[0066] Example 2

[0067] The purpose of this embodiment is to introduce the oxogroup atom clusters prepared in Example 1 into the perovskite precursor solution to prepare oxogroup element-doped perovskite thin films.

[0068] Preferably, in this embodiment, a wide-bandgap perovskite with a bandgap of 1.68 eV is used for Se doping to verify the performance of perovskite thin films doped with oxalic elements.

[0069] The method for preparing the oxalite-doped perovskite thin film provided in this embodiment is as follows:

[0070] (1) Preparation of the perovskite precursor solution system: 1.44 mmol FAI, 0.36 mmol CsI, 1.26 mmol PbI2 and 0.54 mmol PbBr2 were dissolved in a mixed solution of DMF (N,N-dimethylformamide) and the cluster solution (DMSO containing Se clusters) prepared in Example 1, wherein the volume ratio of DMF to DMSO was 4:1. Then, the solution was stirred continuously for 2 h at 45 °C to ensure complete dissolution, thus preparing the FA solution. 0.8 Cs 0.2Pb(I 0.8 Br 0.2 )3 (band gap of 1.68 eV) perovskite precursor solution, the concentration of perovskite precursor solution is 1.8 mmol / mL;

[0071] (2) Substrate preparation: Dry the cleaned indium tin oxide conductive glass with nitrogen gas, put it into an ultraviolet ozone cleaner and treat it for 30 minutes. After the treatment, transfer the substrate to a glove box.

[0072] (3) FA 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 3. The perovskite precursor solution was spin-coated at a speed of 5000 r / min for 30 s, with ethyl acetate added dropwise in the last 10 s. After the spin-coating was completed, the film was heated at 100 ℃ for 10 min to generate the perovskite phase, thus obtaining a perovskite film doped with chalcogen elements, referred to as a perovskite film.

[0073] The perovskite thin film prepared above was subjected to time-of-flight secondary mass spectrometry (TOF-SIMS) testing, and the test results are as follows: Figure 4 As shown. The results indicate that Se 2- The presence of ions in the perovskite bulk phase, and their distribution trend being similar to that of Br and I ions, indicates that Se atom clusters are uniformly distributed in the perovskite film.

[0074] Simultaneously, the prepared perovskite film was ground into powder to eliminate the influence of stress, and tested using a synchrotron X-ray diffractometer (XRD). The test results are as follows: Figure 5 As shown in the figure. The results indicate that no new phase appears in the XRD pattern of the Se-doped perovskite. However, after magnification of the (100), (200), and (300) diffraction peaks, it was found that the peak positions of the Se-doped perovskite film shifted more significantly with the increase of 2θ. This phenomenon indicates that Se ions replace the smaller I ions in the perovskite lattice, thus having a significant impact on the lattice. All the above results prove that the present invention successfully prepared a Se-doped perovskite film.

[0075] Comparative Example 1

[0076] This comparative example prepared an undoped perovskite and compared it with the Se-doped perovskite film in Example 2 to further verify the performance difference between Se-doped perovskite and undoped perovskite.

[0077] In this comparative example, the method for preparing undoped perovskite is as follows:

[0078] (1) Preparation of perovskite precursor solution: 1.44 mmol FAI, 0.36 mmol CsI, 1.26 mmol PbI2 and 0.54 mmol PbBr2 were dissolved in a mixed solution of DMF (N,N-dimethylformamide) and DMSO, wherein the volume ratio of DMF to DMSO was 4:1. Then, the solution was stirred continuously for 2 h at 45 °C until completely dissolved, thus preparing the FA precursor solution. 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 )3 (band gap of 1.68 eV) perovskite precursor solution, concentration of 1.8 mmol / mL;

[0079] (2) Substrate preparation: Dry the cleaned indium tin oxide conductive glass with nitrogen gas, put it into an ultraviolet ozone cleaner and treat it for 30 minutes. After the treatment, transfer the substrate to a glove box.

[0080] (3) FA 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 3. The perovskite precursor solution was spin-coated at 5000 r / min for 30 s, with ethyl acetate added dropwise in the last 10 s. After the spin-coating was completed, the film was heated at 100 °C for 10 min to generate the perovskite phase, resulting in an undoped perovskite film.

[0081] Furthermore, the performance of the Se-doped perovskite film in Example 2 and the perovskite film in Comparative Example 1 were tested as follows to verify the performance difference between Se-doped perovskite and undoped perovskite.

[0082] Test 1

[0083] Photoluminescence spectrum surface scans were performed on the Se-doped perovskite film of Example 2 and the perovskite film of Comparative Example 1, respectively, to obtain the fluorescence peak position surface scans of the two films, as shown below. Figure 6 As shown in the figure. The results show that the surface scan of the Se-doped perovskite film shows only one color, while the surface scan of the undoped perovskite film shows two colors, distributed in a stripe pattern. The test results indicate that the uniformity of the perovskite film is significantly improved after Se doping.

[0084] Test 2

[0085] Time-resolved photoluminescence spectroscopy (TRPL) tests were performed on the Se-doped perovskite film in Example 2 and the perovskite film in Comparative Example 1, respectively. Figure 7As shown, TRPL exhibits two decay components: rapid decay and slow decay. Compared to undoped perovskite films, Se-doped perovskite films show improvements in both decay components, indicating that Se doping reduces both charge carrier filling defects and perovskite surface defects.

[0086] The above results indicate that Se-doped perovskite films have higher crystal quality and lower defect density.

[0087] Test 3

[0088] Photoluminescence (PL) tests were performed on the Se-doped perovskite film of Example 2 and the perovskite film of Comparative Example 1. The results showed that when tracking the photoinduced phase separation phenomenon of the perovskite film using PL testing, it was found that the perovskite film without Se atom clusters precipitated an I-rich phase on its surface after illumination. Figure 8 As shown, the PL peak shifted from the original 739 nm to 778 nm (approximately 1.59 eV). However, no phase separation occurred in the wide-bandgap perovskite film after the implantation of Se atom clusters within 14 days.

[0089] Test 4

[0090] By analyzing the morphology of the perovskite thin film before and after illumination, such as... Figure 9 As shown, a large amount of white phase was found on the surface of the undoped Se atom cluster perovskite film, which is similar to the PbI2 phase. Simultaneously, the cross-sectional SEM images showed blurred grain boundaries and the presence of numerous precipitates, all of which provide evidence for the precipitation of the I-rich phase. However, the surface and cross-sectional SEM images of the Se-doped perovskite film did not show significant changes.

[0091] The above results indicate that Se-doped perovskite films exhibit good photostability.

[0092] Through the above performance tests, the wide-bandgap perovskite thin film prepared by introducing oxalate clusters into perovskite materials in this invention has significantly improved light stability, high crystal quality and reduced defect density, thereby reducing halogen vacancy defects, increasing ion migration barrier and improving the photoelectric performance of perovskite solar cells.

[0093] Example 3

[0094] In this embodiment, a wide-bandgap perovskite with a bandgap of 1.78 eV is used for Se doping.

[0095] The method for preparing the oxalite-doped perovskite thin film provided in this embodiment is as follows:

[0096] (1) Preparation of perovskite precursor solution: 1.44 mmol FAI, 0.36 mmol CsI, 0.72 mmol PbI2 and 1.08 mmol PbBr2 were dissolved in a mixed solution of DMF (N,N-dimethylformamide) and DMSO containing Se clusters (the cluster solution prepared in Example 1), wherein the volume ratio of DMF to DMSO was 4:1. Then, the solution was stirred continuously for 2 h at 45 °C to ensure complete dissolution, thus preparing FA. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 (band gap of 1.78 eV) perovskite precursor solution, concentration of 1.8 mmol / mL;

[0097] (2) Substrate preparation: Dry the cleaned indium tin oxide conductive glass with nitrogen gas, put it into an ultraviolet ozone cleaner and treat it for 30 minutes. After the treatment, transfer the substrate to a glove box.

[0098] (3) FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 3. The perovskite precursor solution was spin-coated into a film at a speed of 5000 r / min for 30 s. Ethyl acetate was added dropwise in the last 10 s. After the spin-coating was completed, the film was heated at 100 ℃ for 10 min to generate the perovskite phase.

[0099] Furthermore, undoped perovskite films with a band gap of 1.78 were prepared using the method of Comparative Example 1, and their PL performance was compared.

[0100] When using PL testing to track photoinduced phase separation in perovskite thin films, such as Figure 10 The study showed that the perovskite film without Se clusters began to undergo phase segregation 10 minutes after illumination. At 50 minutes, the peak position of the perovskite film shifted, and the main peak of the perovskite film turned to 740 nm (approximately 1.68 eV) after 90 minutes, while a wide gap phase of 1.78 eV was still present. However, although the perovskite film doped with Se clusters also showed a peak of 740 nm after 90 minutes of illumination, its main peak remained at 695 nm.

[0101] The above results demonstrate that Se-doped wide-bandgap perovskite films still exhibit good photostability even with increased Br content.

[0102] Example 4

[0103] This embodiment applies the oxalite-doped perovskite thin film prepared in Example 2 to a solar cell. Specifically, a wide bandgap perovskite with a bandgap of 1.68 eV is used for Se doping to further verify the performance changes of the oxalite-doped perovskite solar cell.

[0104] In this embodiment, a solar cell is fabricated using a perovskite thin film doped with group oxalates, comprising the following steps:

[0105] (1) Preparation of perovskite precursor solution: 1.44 mmol FAI, 0.36 mmol CsI, 1.26 mmol PbI2 and 0.54 mmol PbBr2 were dissolved in a mixed solution of DMF (N,N-dimethylformamide) and DMSO containing Se clusters (prepared in Example 1), wherein the volume ratio of DMF to DMSO was 4:1. Then, the solution was stirred continuously for 2 h at 45 °C to ensure complete dissolution, thus preparing FA. 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 )3 (band gap of 1.68 eV) perovskite precursor solution, concentration of 1.8 mmol / mL;

[0106] (2) Substrate preparation: Dry the cleaned indium tin oxide conductive glass with nitrogen gas, place it in an ultraviolet ozone cleaner for 30 min, and spin-coat NiO on the substrate after the treatment. x An aqueous solution (concentration 20 mg / mL) was heated at 120 °C for 10 min after the reaction to form NiO. x After the film is removed, it is transferred to the glove box;

[0107] (3) Spin-coat an ethanol solution of Me-4PACz (concentration of 1 mg / mL) onto NiO. X On the thin film, the rotation speed is 3000 r / min for 30 s; after the end, it is heated at 100 ℃ for 10 min to obtain the double hole transport layer substrate.

[0108] (4) FA 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 )3. The perovskite precursor solution was spin-coated onto the hole transport layer at a speed of 5000 r / min for 30 s. Ethyl acetate was added dropwise in the last 10 s. After the spin-coating was completed, the mixture was heated at 100 ℃ for 10 min to generate the perovskite phase and obtain the perovskite absorption layer.

[0109] (4) Spin-coat a chlorobenzene solution (20 mg / mL) of PCBM onto the perovskite at a speed of 1500 r / min for 30 s. Then spin-coat a solution of isopropanol of BCP onto it and drop-coat it dynamically at a speed of 4000 r / min. Finally, heat it at 70 ℃ for 10 min to obtain the electron transport layer.

[0110] (5) A silver electrode layer with a thickness of 100 nm is deposited on the electron transport layer using a thermal evaporation method to obtain a pin-type solar cell.

[0111] Furthermore, the undoped perovskite thin film from Comparative Example 1 was applied to a solar cell to prepare... Type of solar cell.

[0112] For the two assembled above The performance of the solar cell was tested, and its JV curve results are as follows: Figure 11 As can be seen from the curve labeled Se, the solar cell formed by the perovskite thin film doped with oxalic elements achieves a photoelectric conversion efficiency of 23.17%.

[0113] It should be noted that in Examples 2-4, the perovskite material is A. a B b X c The perovskite structure; A, B, and X are substituted in the following materials, where A is CH3NH3. + HC(NH2)2 + Cs + or Rb + B is Pb 2+ and Sn 2+ X is a halide ion (I − ,Br − or Cl − (Ions) and oxalic elements (Se, S, or Te). After substitution, it exhibits the same or similar properties as in Examples 2 and 4.

[0114] It should be noted that in Example 4, the thickness of the perovskite absorber layer is arbitrarily selected within the range of 200 nm to 900 nm, the thickness of the electron transport layer is arbitrarily selected within the range of 10 nm to 120 nm, and the thickness of the hole transport layer is arbitrarily selected within the range of 10 nm to 300 nm. In Example 4, the material of the electron transport layer can be replaced with other n-type inorganic semiconductor materials or organic semiconductor materials, specifically C... 60 One or more of PCBM, SnO2, etc., the hole transport layer material can be replaced with other p-type semiconductors, specifically NiO. XOne or more of PTAA, Me-4PACz, and Spiro-OMeTAD are used. The solar cells prepared after the substitution exhibit the same or similar photoelectric conversion performance as those in Example 4.

[0115] Therefore, this invention provides a perovskite thin film doped with oxogroup atomic clusters and oxogroup elements, and its application in solar cells. It utilizes liquid-phase pulsed irradiation technology to obtain a series of oxogroup atomic clusters and solves the technical problem of pseudohalogen-doped perovskite thin films in existing technologies. When preparing perovskite using oxogroup atomic clusters, the oxogroup elements can regulate the perovskite crystallization process, resulting in a perovskite thin film with high crystal quality and few defects. This perovskite thin film is also suitable for preparing... Type structure, The perovskite solar cell with a unique structure enhances the photoelectric performance of perovskite solar cells and meets the application requirements of solar cells.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a chalcogenide cluster, characterized in that, The preparation method includes the following steps: S1. Based on liquid-phase pulsed irradiation technology, laser irradiation is performed simultaneously with ultrasonic treatment of a target solution containing oxalic materials under a nitrogen atmosphere; S2. The target solution containing oxalic materials is treated with liquid nitrogen freezing step S1, then subjected to laser irradiation, and then thawed. S3. Repeat step S2 multiple times to obtain oxalic atom clusters coordinated with the target solution.

2. The method for preparing chalcogenide clusters according to claim 1, characterized in that, The oxometallic material is sulfur powder, selenium powder, or tellurium powder; the target solution is dimethyl sulfoxide, ethanol, or isopropanol; the ratio of oxometallic material to target solution is 0.015 mg: 10 mL.

3. The method for preparing chalcogenide clusters according to claim 1, characterized in that, The purity of the oxalic material is 99.99%, and the particle size is 200 mesh.

4. The method for preparing chalcogenide clusters according to claim 1, characterized in that, In steps S1 and S2, the laser irradiation conditions are as follows: laser wavelength is 1064 nm, frequency is 10 Hz, pulse width is 8 ns, beam diameter is 8 mm; intensity is 600 J / pulse cm. 2 -1.2 J / pulse cm 2 The time is 3 min-5 min; the intensity of laser irradiation in step S1 is lower than the intensity of laser irradiation in step S2.

5. A perovskite thin film doped with chalcogen elements, characterized in that, The perovskite thin film is formed by introducing an atomic cluster solution into a perovskite precursor solution and depositing it by a one-step spin coating or a two-step sequential method, wherein the atomic cluster solution is prepared by any of the methods in claims 1-4.

6. The perovskite thin film doped with chalcogenide elements according to claim 5, characterized in that, The concentration of the perovskite precursor solution was 1.8 mmol / mL; the solution used in the perovskite precursor solution was N,N-dimethylformamide; the volume ratio of N,N-dimethylformamide to the cluster solution was 4:

1.

7. The application of the oxalite-doped perovskite thin film according to claim 5 in solar cells.

8. The application according to claim 7, characterized in that, The solar cell is Type structure; the The structure is arranged in the following order: conductive substrate, electron transport layer, perovskite absorber layer, hole transport layer and back electrode. The perovskite absorber layer is a perovskite thin film doped with group A elements, and the structure of the perovskite absorber layer is A. a B b X c A mixture of one or more of the following, wherein A is CH3NH3 + HC(NH2)2 + Cs + or Rb + B is Pb 2+ or Sn 2+ X represents halide ions and oxalic elements.

9. The application according to claim 7, characterized in that, The solar cell is Type structure; the The structure is arranged in the following order: conductive substrate, hole transport layer, perovskite absorber layer, electron transport layer and back electrode. The perovskite absorber layer is a perovskite thin film doped with group A elements, and the structure of the perovskite absorber layer is A. a B b X c A mixture of one or more of the following, wherein A is CH3NH3 + HC(NH2)2 + Cs + or Rb + B is Pb 2+ or Sn 2+ X represents halide ions and oxalic elements.

10. The application according to claim 8 or 9, characterized in that, The thickness of the perovskite absorber layer is 200 nm-900 nm; The electron transport layer is made of n-type inorganic semiconductor material or organic semiconductor material, and the thickness of the electron transport layer is 10 nm-120 nm. The hole transport layer is made of a p-type semiconductor, and the thickness of the hole transport layer is 10 nm-300 nm. The back electrode is a metal electrode with a thickness of 100 nm.

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