A method for preparing high-quality tin-based halide perovskite film

Abstract

The present invention discloses a method for preparing a high-quality tin-based halide perovskite film, and belongs to the technical field of perovskite photoelectric devices. The preparation method comprises the following steps: dissolving an organic amine halide and a tin halide in an organic solvent to obtain a mixed solution; heating and stirring the mixed solution to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution on a substrate, and then annealing to obtain the high-quality tin-based halide perovskite film; the organic solvent is N,N-dimethylacetamide. The tin-based perovskite film prepared by the preparation method of the present invention has higher environmental stability, reduces the defect state density of the film, improves the stability of divalent tin, and increases the carrier lifetime. The high-quality tin-based halide perovskite film prepared by the present invention can be applied to the fields of perovskite light-emitting diodes, perovskite solar cells, perovskite photodetectors, etc.

Description

Technical Field

[0001] The invention relates to the technical field of perovskite photoelectric devices, and in particular to a method for preparing a high-quality tin-based halide perovskite film. Background Art

[0002] As an emerging photoelectric conversion material, perovskite has made significant progress in many fields, especially in the application of perovskite solar cells and light-emitting diodes, and its efficiency has already exceeded 20%. However, the development of lead-based perovskites has encountered a bottleneck. Heavy metal lead can cause damage to the human body and the environment. Therefore, the further commercial application of lead-based perovskites is limited. Based on this, lead-free perovskite materials have become one of the most concerned scientific research in this field.

[0003] Tin and lead have similar radius and electronic structure, so tin is considered to be the most likely material to replace lead. However, the photoelectric conversion efficiency of tin-based perovskites is much lower than that of lead-based perovskites. According to previous reports, the main reasons limiting the efficiency improvement of tin-based perovskites can be divided into the following two aspects: 1. Divalent tin has poor stability and is easily oxidized to tetravalent tin to form harmful P-type doping; 2. Tin-based perovskites have a fast crystallization rate and poor film coverage. How to overcome the above problems and prepare high-quality tin-based halide perovskite films is a difficult problem faced by technicians in this field at this stage. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a high-quality tin-based halide perovskite film to solve the problems existing in the above-mentioned prior art. The present invention prepares a high-quality tin-based halide perovskite film by a one-step spin coating method. The preparation method is simple, low-toxic, convenient, low-cost, mild conditions, and conducive to large-scale production. The stability of the tin-based halide perovskite film can be improved, and the efficiency of the perovskite light-emitting diode can be improved.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: a method for preparing a high-quality tin-based halide perovskite film, comprising the following steps:

[0007] Dissolving an organic amine halide and a tin halide in an organic solvent to obtain a mixed solution; heating and stirring the mixed solution to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution on a substrate, and then annealing to obtain the high-quality tin-based halide perovskite film; the organic solvent is N,N-dimethylacetamide (DMA).

[0008] Furthermore, the molar ratio of the organic amine halide to the tin halide is 1.8-2.5.

[0009] Furthermore, the concentration of tin ions in the mixed solution is 0.00001-10 mol / L.

[0010] Furthermore, the tin halide is one or more of tin chloride, tin bromide and tin iodide.

[0011] Furthermore, the organic amine in the organic amine halide is one or more of benzylamine (PMA), phenethylamine (PEA), phenbutylamine (PBA), thiopheneethylamine (TEA), thiophenemethylamine (TMA), butylamine (BA) and propylamine (BDA).

[0012] Furthermore, the halogen in the halide of the organic amine is one or more of chlorine, bromine and iodine.

[0013] That is, the halide of the organic amine can be represented by AX, wherein A represents an organic amine, X represents a halogen, A is one or more of benzylamine, phenethylamine, phenbutylamine, thiopheneethylamine, thiophenemethylamine, butylamine and propylamine, and X is one or more of chlorine, bromine and iodine.

[0014] Furthermore, the heating and stirring is carried out at a temperature of 20-120° C. and for a time of 0.1-58 h.

[0015] Furthermore, the annealing treatment is performed at a temperature of 10-200° C. and for a time of 200 h.

[0016] The second technical solution of the present invention: a high-quality tin-based halide perovskite film prepared by the above-mentioned preparation method.

[0017] Technical solution three of the present invention: Application of the above-mentioned high-quality tin-based halide perovskite film in the preparation of perovskite light-emitting diodes, perovskite solar cells, perovskite photodetectors, perovskite fluorescent films, perovskite phosphors or perovskite semiconductor transistors.

[0018] The present invention discloses the following technical effects:

[0019] The preparation method of the present invention has many significant advantages, including simple operation, low cost, mild conditions and low toxicity, which is very conducive to large-scale production. More importantly, this preparation method can significantly improve the stability of tin-based halide perovskite films and effectively improve the efficiency of perovskite light-emitting diodes prepared using tin-based halide perovskite films. Specifically, its benefits are mainly reflected in the following aspects:

[0020] First, the preparation method of the present invention successfully inhibits the oxidation of divalent tin, significantly reduces the defect state density of the tin-based perovskite film, and improves the carrier lifetime. This not only enhances the electroluminescent efficiency, but also greatly improves the overall stability of the device and the film.

[0021] Secondly, the raw materials used in the preparation method of the present invention are affordable and the preparation process is simple and intuitive, so it is very suitable for large-scale production. This makes the preparation method of the present invention have the outstanding characteristics of lead-free and high efficiency in the field of perovskite light-emitting diodes, which is not inferior to lead-based perovskites.

[0022] In addition, the preparation method of the present invention also significantly improves the photoelectric conversion efficiency of perovskite solar cells and the external quantum efficiency of perovskite light-emitting diodes.

[0023] Finally, the lead-free, high-efficiency and stable tin-based halide perovskite film prepared by the present invention has a wide range of application prospects. It can be applied not only to perovskite light-emitting diodes and solar cells, but also to detectors, fluorescent films, phosphors, semiconductor transistors and other fields, providing new possibilities for related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 XRD spectra of the tin-based halide perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0026] Figure 2 PL spectra of the tin-based halide perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0027] Figure 3 is a SEM image of the tin-based halide perovskite film prepared in Example 1;

[0028] Figure 4 is a SEM image of the tin-based halide perovskite film prepared in Comparative Example 1;

[0029] Figure 5 The XPS test results of the tin-based halide perovskite film prepared in Example 1;

[0030] Figure 6 The XPS test results of the tin-based halide perovskite film prepared in Comparative Example 1;

[0031] Figure 7 PL test results of the perovskite films prepared in Example 1 and Comparative Example 1 at different times;

[0032] Figure 8The brightness-current density test results of the perovskite light-emitting diode prepared by the preparation method of Example 1 and the perovskite light-emitting diode prepared by the preparation method of Comparative Example 1;

[0033] Fig. 9 The external quantum efficiency-current density test results of the perovskite light-emitting diode prepared by the preparation method of Example 1 and the perovskite light-emitting diode prepared by the preparation method of Comparative Example 1;

[0034] Fig.10 The photoelectric conversion efficiency (PCE) test results of the perovskite solar cell prepared by the preparation method of Example 1 and the perovskite solar cell prepared by the preparation method of Comparative Example 1 are shown. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0037] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0038] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0039] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0040] The substrate used in the following embodiments and comparative examples is ITO conductive glass. In addition, any smooth substrate that can be spin-coated with a solution to form a film can also be selected without affecting the presentation of the technical effect.

[0041] The only difference between Example 1, Comparative Example 1 and Comparative Example 2 is the type of solvent, and other conditions (including the spin coating area on the substrate and the spin coating time, etc.) are the same.

[0042] Example 1

[0043] A method for preparing a high-quality tin-based halide perovskite film, the steps are as follows:

[0044] (1) PEAI (phenylethylamine iodide, i.e., iodide of PEA) and SnI2 were dissolved in a solvent DMA at a molar ratio of 2:1 to obtain a mixed solution in which the concentration of Sn ions was 0.2 mmol / mL.

[0045] (2) heating and stirring the mixed solution obtained in step (1) on a hot plate at 60° C. for 2 h to obtain a perovskite precursor solution; filtering the perovskite precursor solution, taking 50 μL of the perovskite precursor solution, dropping it on the substrate, and spin coating it at a speed of 5000 rpm for 80 s, followed by annealing at 80° C. for 5 min to obtain a high-quality tin-based halide perovskite film.

[0046] Comparative Example 1

[0047] A method for preparing a tin-based halide perovskite film, comprising the following steps:

[0048] (1) PEAI and SnI2 were dissolved in a solvent DMF (dimethylformamide) at a molar ratio of 2:1 to obtain a mixed solution in which the concentration of Sn ions was 0.2 mmol / mL.

[0049] (2) heating and stirring the mixed solution obtained in step (1) on a hot plate at 60° C. for 2 h to obtain a perovskite precursor solution; filtering the perovskite precursor solution, taking 50 μL of the perovskite precursor solution, dropping it on the substrate, and spin coating it at a speed of 5000 rpm for 80 s, followed by annealing at 80° C. for 5 min to obtain a tin-based halide perovskite film.

[0050] Comparative Example 2

[0051] A method for preparing a tin-based halide perovskite film, comprising the following steps:

[0052] (1) PEAI and SnI2 were dissolved in a mixed solvent of DMF (dimethylformamide) and DMA in a volume ratio of 1:1 at a molar ratio of 2:1 to obtain a mixed solution in which the concentration of Sn ions was 0.2 mmol / mL.

[0053] (2) heating and stirring the mixed solution obtained in step (1) on a hot plate at 60° C. for 2 h to obtain a perovskite precursor solution; filtering the perovskite precursor solution, taking 50 μL of the perovskite precursor solution, dropping it on the substrate, and spin coating it at a speed of 5000 rpm for 80 s, followed by annealing at 80° C. for 5 min to obtain a tin-based halide perovskite film.

[0054] Test Example 1

[0055] First, the tin-based halide perovskite films prepared in Example 1, Comparative Example 1 and Comparative Example 2 were subjected to XRD test and PL test.

[0056] Figure 1 The XRD spectra of the three are shown in Figure 1 (where Pristine represents Comparative Example 1, TWO represents Comparative Example 2, and DMA represents Example 1). It can be seen that the tin-based halide perovskite films prepared in Example 1, Comparative Example 1 and Comparative Example 2 all show a diffraction peak of (00k), indicating that the perovskite conforms to the n=1 structure. By comparison, it can be seen that among the three samples, the film using DMA solvent has the highest diffraction peak intensity, indicating that the use of DMA solvent can improve the crystallization of the film.

[0057] Figure 2 The PL spectra of the three are shown in Figure 1 (Pristine represents Comparative Example 1, TWO represents Comparative Example 2, and DMA represents Example 1). By comparison, it can be seen that the film prepared in Example 1 with DMA as solvent has a higher PL intensity, which means that the preparation of tin-based halide perovskite films with DMA as solvent can significantly inhibit non-radiative recombination, which is beneficial to improving device performance.

[0058] From the comparison results of XRD spectra and PL spectra, it can be seen that the tin-based halide perovskite film prepared in Example 1 using DMA as solvent has better crystallinity and shows higher PL intensity, indicating that the defect state density in the film is reduced.

[0059] Secondly, the tin-based halide perovskite films prepared in Example 1 and Comparative Example 1 were subjected to SEM testing and XPS testing.

[0060] Figure 3 and Figure 4 Respectively, Example 1 ( Figure 3 ) and Comparative Example 1 ( Figure 4), by comparing the morphology of the perovskite film with the SEM image, it can be seen that the perovskite film prepared in Example 1 using DMA as solvent has fewer voids and a higher film coverage, which is beneficial to reducing the device leakage current.

[0061] Figure 5 and Figure 6 Respectively, Example 1 ( Figure 5 ) and Comparative Example 1 ( Figure 6 ) of Sn 3d. By comparing the antioxidant capacity of the Sn-based halide perovskite film with XPS, it can be seen that the Sn-based halide perovskite film prepared in Example 1 using DMA as a solvent significantly improves the antioxidant capacity of the film and reduces the Sn 4+ content, which is beneficial to slow down Sn 2+ The harmful P-type doping caused by oxidation is crucial to improving device performance. Moreover, the XPS spectrum of Sn 3d in the tin-based halide perovskite film prepared with DMA as solvent shifts to low binding energy (from 494.58 eV to 494.15 eV), indicating that DMA and Sn 2+ There is a strong interaction between them.

[0062] Finally, PL tests were performed on the tin-based halide perovskite films prepared in Example 1 and Comparative Example 1 at different times to evaluate the stability of the films in air.

[0063] Figure 7 The PL test results of the tin-based halide perovskite films prepared in Example 1 and Comparative Example 1 at different times (where Pristine represents Comparative Example 1 and DMA represents Example 1). Figure 7 It can be seen that the PL stability of the film obtained with DMA as solvent has been significantly improved. After being exposed to air for 60 minutes, the PL intensity can still maintain more than 50%, indicating that DMA solvent can improve the stability of the film, which can be attributed to the interaction between DMA and Sn. 2+ There is interaction between them.

[0064] According to the XRD, PL, SEM and XPS test results, the tin halide perovskite film obtained in Example 1 using DMA as solvent can improve the antioxidant capacity of the film. 2+ There is a strong interaction between them, avoiding Sn 2+ There is charge transfer between DMA and Sn, which causes oxidation. 2+The interaction between them also slows down the crystallization rate of tin-based perovskite. Based on this, the tin halide perovskite film obtained with DMA as solvent has higher coverage, better crystallinity and lower defect state density. The reason why the film prepared in comparative example 1 with DMF as solvent is of poor quality is that the coordination ability between DMF and tin is weak, which makes the film crystallization rate too fast and the film quality is poor.

[0065] Application Example 1

[0066] The preparation methods of Example 1 and Comparative Example 1 are applied to prepare perovskite light-emitting diodes

[0067] The preparation process is: prepare a tin-based halide perovskite film on a hole transport layer using the preparation methods of Example 1 and Comparative Example 1, respectively, and then evaporate an electron transport layer and lithium fluoride and a metal electrode aluminum on the annealed tin-based halide perovskite film, respectively, to obtain two perovskite light-emitting diode devices (except for the preparation method of the tin-based halide perovskite film, the other preparation conditions of the two devices are the same). The brightness and electroluminescence efficiency (EQE) of the two perovskite light-emitting diode devices were tested using a CS200 brightness meter and a Keithley2400 source meter. The brightness-current density test results are shown in FIG. Figure 8 As shown, the external quantum efficiency-current density test results are as follows Fig. 9 As shown by Figure 8-9 (wherein Pristine represents a perovskite light-emitting diode prepared by the preparation method of Comparative Example 1, and DMA represents a perovskite light-emitting diode prepared by the preparation method of Example 1) It can be seen that the perovskite light-emitting diode device obtained by preparing the tin-based halide perovskite film by the preparation method of Example 1 (i.e., using DMA as a solvent) shows higher brightness and significantly improved external quantum efficiency, which can be attributed to the improvement of the morphology of the tin-based halide perovskite film and the suppression of non-radiative recombination.

[0068] Application Example 2

[0069] The preparation methods of Example 1 and Comparative Example 1 are applied to prepare perovskite solar cells

[0070] The preparation process is: prepare a tin-based halide perovskite film on a PEDOT:PSS hole transport layer using the preparation methods of Example 1 and Comparative Example 1 respectively, then transfer the annealed tin-based halide perovskite film to a vacuum coating machine, and then evaporate the electron transport layer and metal electrode gold (Au) to obtain a perovskite solar cell device (except for the preparation method of the tin-based halide perovskite film, the other preparation conditions of the two devices are the same). The photoelectric conversion efficiency (PCE) of the two perovskite solar cell devices was tested using a Keithley 2450 source meter and an AM1.5 solar simulator. The photoelectric conversion efficiency (PCE) test results, i.e., the current density-voltage change, are shown in FIG. Fig.10 As shown (wherein Pristine represents the perovskite solar cell prepared by the preparation method of Comparative Example 1, and DMA represents the perovskite solar cell prepared by the preparation method of Example 1). It can be seen that the photoelectric conversion efficiency of the perovskite solar cell obtained by preparing the tin-based halide perovskite film by the preparation method of Comparative Example 1 is 1.48%, and the current density is relatively low. This is due to the low carrier extraction efficiency caused by the high defect state density in the pristine film. The PCE of the perovskite solar cell device obtained by preparing the tin-based halide perovskite film by the preparation method of Example 1 is increased to 2.52%, which fully demonstrates that the film prepared with DMA as the solvent has a lower defect density, and electrons and holes can be separated, thereby improving the photoelectric conversion efficiency of the solar cell.

[0071] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a high-quality tin-based halide perovskite film, characterized in that: The following steps are involved: dissolving an organic amine halide and a tin halide in an organic solvent to obtain a mixed solution; heating and stirring the mixed solution to obtain a perovskite precursor solution; The perovskite precursor solution is spin-coated on a substrate, and then annealed to obtain the high-quality tin-based halide perovskite film; the organic solvent is N,N-dimethylacetamide; The molar ratio of the organic amine halide to the tin halide is 1.8-2.5; The concentration of tin ions in the mixed solution is 0.00001-10 mol / L; The annealing treatment was performed at a temperature of 80° C. and for a time of 5 minutes.

2. The preparation method according to claim 1, characterized in that The tin halide is one or more of tin chloride, tin bromide and tin iodide.

3. The preparation method according to claim 1, characterized in that: The organic amine in the organic amine halide is one or more of benzylamine, phenethylamine, phenbutylamine, thiopheneethylamine, thiophenemethylamine, butylamine and propylamine.

4. The preparation method according to claim 1, characterized in that: The halogen in the organic amine halide is one or more of chlorine, bromine and iodine.

5. The preparation method according to claim 1, characterized in that: The heating and stirring is performed at a temperature of 20-120° C. and for a time of 0.1-58 h.

6. A high-quality tin-based halide perovskite film prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the high-quality tin-based halide perovskite film as claimed in claim 6 in the preparation of perovskite light-emitting diodes, perovskite solar cells, perovskite photodetectors, perovskite fluorescent films, perovskite phosphors or perovskite semiconductor transistors.

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