Post-deposition treatment method of antimony selenide thin film and solar cell

Abstract

This invention provides a post-deposition processing method for antimony selenide thin films and a solar cell, belonging to the field of solar cells. The method includes: coating the surface of the deposited antimony selenide thin film with a processing liquid to form a coating layer on the antimony selenide thin film; wherein the processing liquid includes oxygen and sulfur compounds of phosphorus; subjecting the antimony selenide thin film with the coating layer to gradient-temperature annealing treatment in a nitrogen atmosphere by introducing sulfur vapor to diffuse and dope the phosphorus element in the coating layer into the antimony selenide thin film; and immersing the gradient-temperature annealed antimony selenide thin film in a sulfuric acid ethanol solution for etching to remove residual coating layer. Using the post-deposition processing method provided by this invention to treat the antimony selenide thin film can improve the carrier transport efficiency in the antimony selenide thin film, passivate antisite and vacancy defects in the antimony selenide thin film, suppress nonradiative recombination of carriers, effectively improve the open-circuit voltage and fill factor of the device, and is beneficial to improving the photoelectric conversion efficiency of the device.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more particularly to a post-deposition treatment method for antimony selenide thin films and a solar cell. Background Technology

[0002] Antimony selenide (Sb₂Se₃) has attracted much attention in recent years as a promising light-absorbing material for solar cells due to its excellent photoelectric properties. However, the low symmetry of the quasi-one-dimensional crystal structure of antimony selenide leads to significant anisotropic transport characteristics of charge carriers within the crystal. This necessitates that the antimony selenide films prepared for solar cell applications possess excellent [hk₁] orientation and high crystallinity to facilitate rapid transport of photogenerated charge carriers. Furthermore, modifying the antimony selenide crystal structure to promote charge carrier transport in the [hk₀] direction is considered a more efficient method, but it has not yet been experimentally realized. In addition, the low symmetry of the antimony selenide crystal structure results in numerous non-equivalent atomic sites in the lattice, leading to complex deep-level defect characteristics. Both theoretical calculations and experiments show the existence of complex deep-level defects within the antimony selenide lattice. Especially in antimony-rich films, antimony substitution defects and selenium vacancy defects not only have low formation energies, implying high defect density, but their transition energy levels are also close to the center of the band gap, serving as typical carrier recombination centers. Summary of the Invention

[0003] In view of this, in order to at least partially solve the aforementioned technical problems, the present invention provides a post-deposition processing method for antimony selenide thin films and a solar cell, to improve the anisotropy of carrier transport in antimony selenide thin films and passivate deep-level defects in antimony selenide thin films.

[0004] According to one aspect of the present invention, a post-deposition treatment method for antimony selenide thin films is provided, comprising: coating a treatment liquid onto the surface of the deposited antimony selenide thin film to form a coating layer on the antimony selenide thin film; wherein the treatment liquid comprises an oxygen and sulfur compound of phosphorus; subjecting the antimony selenide thin film with the coating layer to gradient heating annealing treatment by introducing sulfur vapor in a nitrogen atmosphere to diffuse and dope the phosphorus element in the coating layer into the antimony selenide thin film; and immersing the gradient heating annealed antimony selenide thin film in a sulfuric acid ethanol solution for etching to remove the residual coating layer.

[0005] According to another aspect of the present invention, a thin film of antimony selenide (sulfide) obtained by the above-described post-deposition treatment method is provided.

[0006] According to another aspect of the present invention, a solar cell is provided, comprising, from bottom to top: a cathode, an electron transport layer, a light absorption layer, a hole transport layer, and an anode; wherein the light absorption layer comprises an antimony selenide (sulfide) thin film, the antimony selenide (sulfide) thin film being obtained by the above-described post-deposition treatment method.

[0007] According to the post-deposition processing method of antimony selenide thin film provided in the above embodiments of the present invention, antimony selenide thin film can be deposited by thermal evaporation or vacuum physical vapor deposition method, and antimony selenide thin film with good [hk1] dominant orientation and high crystallinity can be obtained.

[0008] According to the post-deposition treatment method for antimony selenide thin films provided in the above embodiments of the present invention, performing post-deposition treatment on the antimony selenide thin film in a nitrogen atmosphere can improve the crystallinity and [hk1] orientation of the antimony selenide thin film, induce lattice distortion of antimony selenide, thereby reducing the inter-neighbor spacing, increasing the transport dimension of charge carriers in the antimony selenide thin film, and improving the charge carrier transport efficiency; it also passivates deep-level defects in the antimony selenide thin film and suppresses nonradiative recombination of charge carriers. Furthermore, introducing sulfur vapor into a nitrogen atmosphere for gradient heating annealing can further passivate antisite and vacancy defects in the antimony selenide thin film. Applying the antimony selenide (sulfide) thin film obtained after post-deposition treatment to solar cells can improve the photoelectric conversion efficiency of solar cells. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0010] Figure 1 A flowchart illustrating the post-deposition treatment method for antimony selenide thin films provided in an embodiment of the present invention;

[0011] Figure 2 Figures (a) to (d) are scanning electron microscope images of the antimony selenide films provided in Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention, respectively; wherein Figure (a) corresponds to the antimony selenide film of Comparative Example 1, Figure (b) corresponds to the antimony selenide film of Example 1, Figure (c) corresponds to the antimony selenide film of Comparative Example 2, and Figure (d) corresponds to the antimony selenide film of Example 2.

[0012] Figure 3 The X-ray diffraction (XRD) patterns of the antimony selenide thin films provided in Comparative Example 1 and Example 1 of the present invention are shown below.

[0013] Figure 4Figures (a) to (c) in the figure show the X-ray photoelectron spectroscopy (XPS) of the antimony selenide films provided in Comparative Example 1, Example 1, and Example 2, respectively; wherein Figure (a) corresponds to the antimony selenide film of Comparative Example 1; Figure (b) corresponds to the antimony selenide film of Example 1; and Figure (c) corresponds to the antimony selenide film of Example 2.

[0014] Figure 5 The images are high-angle annular dark-field-scanning transmission electron microscope (HAADF-STEM) images and atomic-resolution energy dispersive spectra of the antimony selenide thin films provided in Example 1 and Comparative Example 1, respectively. Figures (a), (c), (e), and (g) correspond to the antimony selenide thin film of Comparative Example 1, and Figures (b), (d), (f), and (h) correspond to the antimony selenide thin film of Example 1.

[0015] Figure 6 Synchrotron radiation characterization diagrams of the antimony selenide thin films provided in Comparative Example 1 and Example 1, respectively;

[0016] Figure 7 Figures (a) to (c) are deep-level transient spectroscopy (DLTS) characterization diagrams of the antimony selenide thin films provided in Comparative Example 1, Example 1, and Example 2, respectively. Figure (a) corresponds to the antimony selenide thin film of Comparative Example 1; Figure (b) corresponds to the antimony selenide thin film of Example 1; and Figure (c) corresponds to the antimony selenide thin film of Example 2.

[0017] Figure 8 Figure (a) shows the current-voltage curve of the device in Application Example 1, with a photoelectric conversion efficiency of 9.50%. Figure (b) shows the current-voltage curve of the device in Application Example 3, with a photoelectric conversion efficiency of 10.03%. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. However, this invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art. In the accompanying drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated, and the same reference numerals denote the same elements throughout.

[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0020] To address the issues of anisotropic transport characteristics and high defect density in antimony selenide thin films in related technologies, this invention provides a post-deposition processing method for antimony selenide thin films and a solar cell. This post-deposition processing method can improve the anisotropic carrier transport of antimony selenide thin films and passivate deep-level defects in antimony selenide thin films.

[0021] Figure 1 This is a flowchart of a post-deposition treatment method for antimony selenide thin films provided in an embodiment of the present invention.

[0022] According to an exemplary embodiment of the present invention, the present invention provides a post-deposition processing method for antimony selenide thin films, applicable to processing deposited antimony selenide thin films, referencing... Figure 1 As shown, it includes: operations S1 to S3.

[0023] In operation S1, a treatment solution is coated onto the surface of the deposited antimony selenide film to form a coating layer on the antimony selenide film; wherein the treatment solution includes a solution of phosphorus oxygen and sulfur compounds.

[0024] In an embodiment of the present invention, the preparation of the deposited antimony selenide thin film includes: depositing the antimony selenide thin film using a thermal evaporation method or a vacuum physical vapor deposition method; and annealing the antimony selenide thin film; the annealing temperature is, for example, 370°C.

[0025] In some embodiments, an antimony selenide thin film is deposited on a substrate using an evaporation method or a vacuum physical vapor deposition method. Specifically, a predetermined weight of antimony selenide powder is weighed and placed in a vacuum thermal evaporation deposition chamber, the substrate is placed on a substrate holder with a heating function, the deposition heating temperature is set, and an antimony selenide thin film is obtained by evaporation and deposition on the substrate.

[0026] According to embodiments of the present invention, antimony selenide thin films with good [hk1] predominant orientation and high crystallinity can be obtained by depositing antimony selenide thin films using evaporation or vacuum physical vapor deposition.

[0027] In some embodiments, the deposition rate of the antimony selenide thin film is 3 nm s. -1 ~6nm s -1 The deposition thickness is 300nm~400nm.

[0028] In some embodiments, the oxygen and sulfur compounds of phosphorus include one or more of phosphorus pentoxide and phosphorus pentasulfide, more preferably phosphorus pentoxide.

[0029] In some embodiments, the solvent used to prepare the treatment solution is one or more of anhydrous ethanol and N,N-dimethylformamide, more preferably anhydrous ethanol.

[0030] According to an embodiment of the present invention, the treatment solution is coated uniformly onto the surface of the antimony selenide film by spin coating.

[0031] In embodiments of the present invention, the spin coating speed of the spin coating solution is 2000~4000 rpm and the spin coating time is 10~30s; more preferably 3000~4000 rpm and the spin coating time is 20~30s; more preferably 3000 rpm and the spin coating time is 30s.

[0032] In some embodiments, the concentration of the treatment solution is 5-20 mg / mL. -1 For example, it can be 5mg / mL -1 10mg mL -1 12.5 mg / mL -1 15mg mL -1 20mg / mL -1 However, it is not limited to the values ​​mentioned; a further preferred value is 5~12.5 mg / mL. -1 More preferably 10 mg / mL -1 This ensures sufficient precursors without producing excessive residues.

[0033] In operation S2, sulfur vapor is introduced into the antimony selenide film with the coating layer in a nitrogen atmosphere for gradient heating annealing, so as to diffuse and dope the phosphorus element in the coating layer into the antimony selenide film.

[0034] In some embodiments, the antimony selenide film with the coating layer is placed in a glove box filled with nitrogen and sulfur vapor is introduced to perform the gradient temperature annealing treatment described above.

[0035] In an embodiment of the present invention, the pressure of the sulfur vapor introduced into the gradient temperature annealing process in a nitrogen atmosphere is 10. -3 Up to 10 -4 Pa.

[0036] In an embodiment of the present invention, the gradient temperature annealing process includes: heating the antimony selenide film with the coating layer formed from 20°C to 30°C to 370°C to 390°C, and holding it at that temperature for 5 min to 8 min.

[0037] In some embodiments, the heating rate from 20°C to 30°C to 370°C to 390°C is 68. o C / min ~ 74 o C / min.

[0038] In some embodiments, a gradient heating annealing method is adopted, wherein the heating stage is, for example, the time to rise from room temperature (25°C) to 370°C is 5 minutes, the annealing temperature is 370~390°C, for example, 370°C, 375°C, 380°C, 385°C, 390°C, but not limited to the values ​​mentioned above; the annealing time is 5~8 minutes, more preferably 380~385°C, the annealing time is 6.5 minutes, more preferably 385°C, the annealing time is 6 minutes.

[0039] In step S3, the annealed antimony selenide film is immersed in an ammonium sulfide ethanol solution for etching to remove any residual coating.

[0040] In some embodiments, the concentration of the ammonium sulfide ethanol solution is 1wt% to 20wt%, for example, 1wt%, 5wt%, 10wt%, 15wt%, or 20wt%, but not limited to the values ​​listed above; preferably 1wt%. If the concentration is too high, it will cause etching damage to the antimony selenide film, and if the concentration is too low, it will not be able to effectively remove the residual coating layer.

[0041] In some embodiments, the etching time is 3s to 120s, more preferably 120s.

[0042] In some embodiments, the etching is followed by rinsing with ultrapure water and drying with nitrogen gas for later use.

[0043] According to an exemplary embodiment of the present invention, the present invention provides a solar cell comprising, from bottom to top: a cathode, an electron transport layer, a light absorption layer, a hole transport layer, and an anode; wherein the light absorption layer comprises the antimony selenide (sulfide) thin film obtained by the above-described post-deposition treatment.

[0044] It should be noted that the materials of the cathode, electron transport layer, and anode are not limited here. For example, the cathode can be fluorine-doped tin dioxide transparent conductive glass (FTO), the electron transport layer can be tin dioxide nanoparticles (SnO2) and cadmium sulfide (CdS), and the anode can be a gold electrode.

[0045] In some embodiments, the cathode is FTO. Before forming an electron transport layer on the FTO, the FTO is pretreated. The pretreatment includes ultrasonically cleaning the FTO sequentially with glass cleaner, ultrapure water, isopropanol, acetone, and anhydrous ethanol for 10-60 minutes, drying it with nitrogen, and then cleaning it with an ultraviolet ozone cleaner for 15-20 minutes.

[0046] In some embodiments, the method for depositing the SnO2 nanoparticle layer preferably includes the following steps: spin-coating a layer of SnO2 nanoparticle aqueous dispersion with a thickness of about 10-30 nm onto the FTO surface, followed by annealing in air at 250°C for 30 min. It should be noted that the parameters and conditions in the SnO2 nanoparticle layer deposition method are not limited herein.

[0047] In some embodiments, the CdS preparation method preferably includes the following steps: depositing a CdS thin film with a thickness of 50-70 nm on an FTO / SnO2 substrate using a chemical bath method. It should be noted that the parameters and conditions in the chemical bath method are not limited here.

[0048] In some embodiments, the method for preparing a gold electrode includes the following steps: depositing a gold electrode with a thickness of 60-80 nm using a thermal evaporation process. It should be noted that the parameters and conditions in the thermal evaporation process are not limited here.

[0049] The following exemplifies the post-deposition processing method of the designed antimony selenide thin film and the solar cell. It should be noted that this example is merely a specific embodiment of the present invention and does not limit the scope of protection of the present invention.

[0050] Example 1

[0051] This embodiment provides a post-deposition treatment method for antimony selenide thin films, including the following steps:

[0052] Step S1: Weigh 0.25g of antimony selenide powder and place it in a tungsten boat. Place the FTO / SnO2 / CdS substrate in a vacuum thermal evaporation chamber, set the substrate temperature to 315℃, and evacuate the chamber to a vacuum level of 5 × 10⁻⁶. -4 Pa and 3nm s -1 A 300 nm thick antimony selenide film was deposited at a certain rate and then annealed at 370 °C for 8 min.

[0053] Step S2: Dissolve 50 mg of phosphorus pentoxide powder in 5 mL of anhydrous ethanol to obtain a concentration of 10 mg / mL. -1 Phosphorus pentoxide ethanol solution; the solution was uniformly spin-coated onto the surface of antimony selenide film at 3000 rpm for 30 s;

[0054] Step S3: Transfer the spin-coated antimony selenide film to a glove box filled with nitrogen for annealing at 385°C for 6 minutes.

[0055] Step S4: Immerse the annealed antimony selenide film in a 1 wt% ammonium sulfide ethanol solution and etch for 120 seconds. Then rinse it with ultrapure water and dry it with nitrogen to obtain the treated antimony selenide film (denoted as P2O5&(NH4)2S-Sb2Se3).

[0056] Example 2

[0057] The antimony selenide thin film was post-deposited using the same method as in Example 1, except that the ethanol solution of phosphorus pentoxide was replaced with an N,N,-dimethylformamide solution of phosphorus pentasulfide at a concentration of 15 mg / mL. -1 The treated antimony selenide film (denoted as P2S5&(NH4)2S-Sb2Se3) was obtained.

[0058] Example 3

[0059] The antimony selenide thin film was post-deposited using the same method as in Example 1, except that sulfur vapor (10) was introduced during the post-annealing process in step S3. -4 Pa), to obtain the treated antimony selenide (sulfide) film (denoted as P2O5&(NH4)2S-S-Sb2Se3).

[0060] Comparative Example 1

[0061] Weigh 0.25g of antimony selenide powder and place it in a tungsten boat. Place the FTO / SnO2 / CdS substrate in a vacuum thermal evaporation chamber, set the substrate temperature to 315℃, and evacuate the chamber to a vacuum level of 5×10⁻⁶. -4 Pa and 3 nm s -1 A 300 nm thick antimony selenide film was deposited at a high rate.

[0062] The antimony selenide film was transferred to a glove box filled with nitrogen for annealing at 370°C for 8 minutes to obtain the antimony selenide film (denoted as Control-Sb2Se3).

[0063] Comparative Example 2

[0064] The antimony selenide thin film was subjected to the same post-deposition treatment as in Example 1, except that the annealing treatment in step S3 was not performed, resulting in an antimony selenide thin film (denoted as P2O5-Sb2Se3).

[0065] Figure 2 Figures (a) to (d) are scanning electron microscope images of the antimony selenide films provided in Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention, respectively; wherein Figure (a) corresponds to the antimony selenide film of Comparative Example 1, Figure (b) corresponds to the antimony selenide film of Example 1, Figure (c) corresponds to the antimony selenide film of Comparative Example 2, and Figure (d) corresponds to the antimony selenide film of Example 2.

[0066] refer to Figure 2As shown in Figures (c) and (b), compared to the smooth surface of the antimony selenide film in Comparative Example 2, the surface of the antimony selenide film in Example 1 is loaded with some particles generated by the coating layer; this illustrates the necessity of annealing treatment in the post-deposition process.

[0067] Figure 3 The X-ray diffraction (XRD) patterns of the antimony selenide thin films provided in Comparative Example 1 and Example 1 of the present invention are shown.

[0068] refer to Figure 3 As shown, compared with the antimony selenide film of Comparative Example 1, the crystallinity of the antimony selenide film provided in Example 1 is improved, and the [hkl] orientation of the antimony selenide film is enhanced.

[0069] Figure 4 Figures (a) to (c) are X-ray photoelectron spectra of the antimony selenide films provided in Comparative Example 1, Example 1, and Example 2, respectively; wherein Figure (a) corresponds to the antimony selenide film of Comparative Example 1; Figure (b) corresponds to the antimony selenide film of Example 1; and Figure (c) corresponds to the antimony selenide film of Example 2.

[0070] refer to Figure 4 As shown in Figures (a) and (c), the binding energy peaks of the antimony selenide films of Example 2 and Comparative Example 1 at binding energies of 54.0 eV and 54.9 eV, respectively, are attributed to the Se3d bonds of the Se-Sb bonds. 5 / 2 and Se3d 3 / 2 Peak, and see Figure 4 As shown in Figure (b), the Se-Sb bond binding energy peaks of the antimony selenide film of Example 1 are slightly shifted to 54.1 eV and 55.0 eV. In addition, binding energy peaks with binding energies of 54.7 eV and 55.6 eV also appear, which are attributed to the formation of Se-P bonds, indicating that the post-processing was successful.

[0071] Figure 5 The images shown are high-angle annular dark-field-scanning transmission electron microscope (HAADF-STEM) images and atomic-resolution energy dispersive spectra of antimony selenide thin films of Example 1 and Comparative Example 1, where Figures (a), (c), (e), and (g) correspond to the antimony selenide thin film of Comparative Example 1, and Figures (b), (d), (f), and (h) correspond to the antimony selenide thin film of Example 1.

[0072] The antimony selenide thin films prepared in Example 1 and Comparative Example 1 were characterized by HAADF-STEM and atomic-resolved energy dispersive spectroscopy, respectively.

[0073] according to Figure 5As shown, in Comparative Example 1, the Se and Sb atomic chains exhibit a regular and ordered arrangement, with only slight offsets in local areas. In contrast, the one-dimensional Se atomic chains in Example 1 become noticeably disordered, even appearing to be cross-linked, and the Sb atoms also show slight positional shifts. This indicates that the crystal structure of the antimony selenide film in Example 1, which underwent post-deposition treatment, has been distorted, causing the antimony selenide crystal chains to move closer together.

[0074] Figure 6 Synchrotron radiation characterization diagrams of the antimony selenide thin films provided in Comparative Example 1 and Example 1, respectively.

[0075] The antimony selenide thin films prepared in Example 1 and Comparative Example 1 were characterized by X-ray absorption near-edge structure (XANES) and analyzed by extended X-ray absorption fine spectroscopy (EXAFS) to conduct an in-depth analysis of the fine crystal structure of the antimony selenide thin films. The results are as follows: Figure 6 As shown.

[0076] Figure 6 The results indicate that the coordination peaks in the 1.5–2 Å range belong to Se-P / S / Cl coordination. The coordination peaks between 2 and 3 Å originate from Se-Sb bonds. Furthermore, the intensities of the Se-Sb and Sb-P / S / Cl coordination peaks decrease, suggesting that P doping reduces the local order of the lattice and induces lattice contraction. Analysis using software such as R-space revealed that after P doping, the bond lengths of the Se-Sb and Se-P / S / Cl bonds slightly lengthened from 2.62 Å and 2.25 Å to 2.64 Å and 2.26 Å, respectively, while the coordination number (N) of the Se-Sb bond decreased from 1.4 to 1.2. This is due to the lattice distortion induced by P doping, causing Se atoms to deviate from their original positions. Therefore, this characteristic not only lengthens the Se-Sb bond but also causes some bonds to break, thereby promoting coordination between Se and P.

[0077] Figure 7 Figures (a) to (c) are deep-level transient spectroscopy (DLTS) characterization diagrams of the antimony selenide thin films provided in Comparative Example 1, Example 1, and Example 2, respectively. Figure (a) corresponds to the antimony selenide thin film of Comparative Example 1; Figure (b) corresponds to the antimony selenide thin film of Example 1; and Figure (c) corresponds to the antimony selenide thin film of Example 2.

[0078] The antimony selenide thin films prepared in Examples 1, 2, and Comparative Example 1 were characterized by DLTS to detect changes in the deep-level defect characteristics of the films. The results are as follows: Figure 7 As shown.

[0079] according to Figure 7 It can be seen that Comparative Example 1 mainly contains one type of electron trap: selenium vacancy V. Se1And three types of hole traps: antimony-substituted selenium antisite defect Sb Se1 Sb Se2 and Sb Se3 In Example 1, V Se1 Sb Se1 and Sb Se3 The defects are passivated and disappear, and a new type of P with weaker recombination effect on charge carriers is formed. Se Defects, the overall defect density in the film decreased significantly. In Example 2, V Se1 The defects were passivated and disappeared, and the density of other defects also decreased significantly. This indicates that the post-deposition treatment method of the present invention can passivate deep-level defects in antimony selenide films.

[0080] Application Example 1

[0081] A method for preparing a solar cell is provided, comprising the following steps:

[0082] (1) FTO was ultrasonically cleaned for 40 min each with glass cleaner, ultrapure water, isopropanol, acetone and anhydrous ethanol, then dried with nitrogen and cleaned with ultraviolet ozone cleaner for 20 min.

[0083] (2) Spin-coat a 15% aqueous dispersion of tin dioxide nanoparticles diluted 5 times with ultrapure water onto the surface of FTO glass. The spin-coating speed is 3000 rpm and the spin-coating time is 30 s. After spin-coating, place the FTO glass on a heating stage and anneal it in air at 250 ℃ for 30 min. After the annealing is completed, allow it to cool naturally to room temperature.

[0084] (3) CdS was deposited on FTO glass coated with SnO2 nanoparticles using a chemical bath deposition method. The specific process was as follows: First, 10 mL of cadmium nitrate solution (0.015 mol L) was measured. -1 ) and 13.5 mL of ammonia water (1.56 mol L) -1 Mix the two together and stir for 1.5 min. Then measure 6.6 mL of thiourea solution (1.50 mol L). -1 Add the solution and stir for 30 seconds. Then, add 70 mL of ultrapure water and stir for 1 minute to obtain the precursor solution. Next, place the washed FTO onto a glass strip, FTO side down, in a glass bottle, and add the precursor solution until the FTO glass is completely submerged. The deposition process is carried out in a 66 °C water bath for 15 minutes. After deposition, remove the FTO glass, rinse it thoroughly with ultrapure water, and dry it with N2. Then, use SbCl3 solution (30 mg / mL) to... -1An ethanol solution was spin-coated onto the deposited CdS surface at 3000 rpm, followed by annealing in air at 400 °C for 10 min. Finally, the FTO / SnO2 / CdS substrate was allowed to cool naturally to room temperature for later use.

[0085] (4) These are steps S1 to S4 of Example 1;

[0086] (5) A Spiro-OMeTAD layer was spin-coated onto the surface of the antimony selenide film as a hole transport layer. The specific process was as follows: First, 36.6 mg of Spiro-OMeTAD powder was dissolved in 1 mL of chlorobenzene in a glove box filled with N2. Then, 14.5 μL of 4-tert-butylpyridine and 9.5 μL of Li-TFSI solution (520 mg / mL) were added. -1 The Li-TFSI acetonitrile solution was shaken thoroughly to ensure homogeneity. The Spiro-OMeTAD solution was spin-coated onto an antimony selenide film at 3000 rpm for 30 s. The film was then annealed in air at 105 °C for 10 min.

[0087] (6) A gold electrode was deposited on the antimony selenide thin film using a thermal evaporation process. The thermal evaporation process specifically involved placing the prepared FTO / SnO2 / CdS / Sb2Se3 / Spiro-OMeTAD thin film in a photomask and fixing it at a depth of 5.0 × 10⁻⁶ mm. -4 A 65 nm thick Au electrode layer was deposited under Pa pressure.

[0088] Application Example 2

[0089] Solar cells were prepared using the same method as in Application Example 1, except that Example 1 in step (4) was replaced with Example 2, while other parameters and conditions were the same as in Application Example 1.

[0090] Application Example 3

[0091] Solar cells were prepared using the same method as in Application Example 1, except that Example 1 in step (4) was replaced with Example 3, while other parameters and conditions were the same as in Application Example 1.

[0092] Comparative Application Example 1

[0093] Solar cells were prepared using the same method as in Application Example 1, except that Example 1 in step (4) was replaced with Comparative Example 1, and other parameters and conditions were the same as in Application Example 1.

[0094] Comparative Application Example 3

[0095] Solar cells were prepared using the same method as in Application Example 1, except that Example 1 in step (4) was replaced with Comparative Example 2, and the other parameters and conditions were the same as in Application Example 1.

[0096] The solar cell devices obtained in Application Examples 1-2 and Comparative Application Examples 1-2 were subjected to bright-state current-voltage (JV) curve tests at 25°C. The light source used was an XES-70S1 type solar simulator with a xenon lamp, and the irradiance of the light source was calibrated to AM1.5 (1000W m²) from a standard monocrystalline silicon cell. -2 Additionally, a Keithley 2400 digital source meter was connected to provide voltage. Tests were conducted under these conditions, and the resulting JV curves are shown in Table 1.

[0097] Table 1

[0098]

[0099] As shown in Table 1, compared with Comparative Application Examples 1-2, the photoelectric conversion efficiency (PCE), open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) of the solar cells in Application Examples 1-2 are all improved. This is because in the embodiments of the present invention, by coating the surface of the deposited antimony selenide thin film with a processing liquid and co-annealing, phosphorus element diffuses and dopes into the antimony selenide thin film, which improves the carrier transport efficiency, passivates the deep-level defects in the antimony selenide thin film, and thus improves the overall performance of the solar cell.

[0100] Figure 8 Figure (a) shows the current-voltage curve of the device in Application Example 1, with a photoelectric conversion efficiency of 9.50%. Figure (b) shows the current-voltage curve of the device in Application Example 3, with a photoelectric conversion efficiency of 10.03%. It can be seen that by introducing sulfur vapor in the post-processing, the device parameters can be significantly improved: the open-circuit voltage increases from 0.469V to 0.545V, the fill factor increases from 66.72% to 68.00%, and ultimately the photoelectric conversion efficiency increases from 9.50% to 10.05%.

[0101] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely 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 within the protection scope of the present invention.

Claims

1. A post-deposition treatment method for antimony selenide thin films, characterized in that, include: A treatment solution is coated on the surface of the deposited antimony selenide film to form a coating layer on the antimony selenide film; The treatment solution includes phosphorus oxygen and sulfur compounds; The antimony selenide film with the coating layer is subjected to gradient heating annealing in a nitrogen atmosphere by introducing sulfur vapor, so as to diffuse and dope the phosphorus element in the coating layer into the antimony selenide film. as well as The antimony selenide film after gradient heating annealing was immersed in an ammonium sulfide ethanol solution for etching to remove the residual coating layer.

2. The post-deposition treatment method according to claim 1, characterized in that, In the gradient temperature annealing process using sulfur vapor introduced into a nitrogen atmosphere, the pressure of the sulfur vapor is 10. -3 Up to 10 -4 Pa; The gradient temperature annealing process includes: heating the antimony selenide film with the coating layer from 20℃~30℃ to 370℃~390℃ and holding it at that temperature for 5min~8min; Preferably, the heating rate from 20℃~30℃ to 370℃~390℃ is 68. o C / min ~ 74 o C / min.

3. The post-deposition treatment method according to claim 1, characterized in that, The preparation of deposited antimony selenide thin films includes: Antimony selenide thin films were deposited using either thermal evaporation or vacuum physical vapor deposition. The antimony selenide film is annealed. Preferably, the annealing temperature is 370°C.

4. The post-deposition treatment method according to claim 1, characterized in that, The phosphorus oxygen and sulfur compounds include one or more of phosphorus pentoxide and phosphorus pentasulfide; Preferably, the solvent used in the treatment solution is one or more of anhydrous ethanol and N,N-dimethylformamide.

5. The post-deposition treatment method according to claim 1, characterized in that, The treatment solution was coated by spin coating. The spin coating speed was 2000 rpm to 4000 rpm and the spin coating time was 10 s to 30 s.

6. The post-deposition treatment method according to claim 1, characterized in that, The concentration of the treatment solution is 5 mg / mL. -1 ~20mg mL -1 .

7. The post-deposition treatment method according to claim 1, characterized in that, The concentration of the ethanol solution of the ammonium sulfide is 1 wt% to 20 wt%.

8. The post-deposition treatment method according to claim 1, characterized in that, The etching time is 3s to 120s.

9. A thin film of antimony selenide (sulfide) obtained by the post-deposition treatment method as described in any one of claims 1 to 8.

10. A solar cell, characterized in that, From bottom to top, they include: Cathode, electron transport layer, light absorption layer, hole transport layer, and anode; The light-absorbing layer includes the antimony selenide (sulfide) thin film as described in claim 9.

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