Room-temperature preparation method of high-yield and high-purity Cs2AgBiBr6 polycrystalline powder

Abstract

The invention discloses a high-yield and high-purity Cs2AgBiBr6 polycrystalline powder room temperature preparation method, which comprises: mixing CsBr powder, AgBr powder and BiBr3 powder, adding DMSO and an anti-solvent, carrying out a room temperature stirring reaction, and after the reaction is finished, carrying out cleaning purification and heating drying on the reaction product to obtain the Cs2AgBiBr6 polycrystalline powder. The Cs2AgBiBr6 polycrystalline powder with the purity close to 100% and the yield reaching 92% is prepared through a simple process under the room temperature condition, a source material is provided for thermal evaporation, sputtering and pulsed laser deposition of a high-quality Cs2AgBiBr6 film, and application of Cs2AgBiBr6 in the aspects of solar cells, photoelectric detection, laser diodes and the like is further promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoelectric material preparation, and specifically relates to a high-yield and high-purity Cs 2 AG 6 Room temperature preparation method for polycrystalline powders. Background Art

[0002] Double perovskite material Cs 2 AG 6 It has the advantages of excellent stability and low toxicity and is widely used in solar cells, photodetectors, laser diodes and other fields. 2 AG 6 Most of the devices are based on CsBr, AgBr and BiBr 3 The powder is used as raw material, mixed in a solvent, and Cs is directly prepared on the substrate by spin coating. 2 AG 6 Thin film, if this method is to improve the performance of the device, it has extremely high requirements on the purity of the raw material powder, resulting in high device cost. At the same time, due to the potential non-stoichiometric ratio and non-double perovskite impurities, this method causes batch differences in device performance. Therefore, optimizing high-purity Cs 2 AG 6 The preparation method is an important strategy to obtain high-performance and high-repetition rate devices.

[0003] Currently, by preparing Cs 2 AG 6 Polycrystalline or single crystal powder (collectively referred to as crystal) and then building devices based on it is the preferred method to solve the above problems. 2 AG 6 Crystal methods often require high temperatures, complex process conditions, and low yields. For example, the literature "Abismuth-halide double perovskite with long carrier recombination lifetime for photovoltaic applications" [1] In this study, the inversion crystallization method was used to prepare millimeter-sized Cs 2 AG 6 Crystals, but the yield was only 56.2%. 2 AG 6double perovskite film for lead-free inverted planar heterojunctionsolar cells with 2.2%efficiency” [2] The above-mentioned inversion crystallization method was improved in the literature. The two-step temperature increase method was used to promote the dissolution of AgBr, and the crystal yield was increased to 68.1%, but the preparation process was more complicated. In order to avoid the solubility problem of AgBr in the wet chemical method, the literature "Cs 2 XT 6 (X=Br,Cl): new visible light absorbing, lead-free halide perovskite semiconductors” [3] Cs was prepared by solid-state reaction. 2 AG 6 Crystals, although they have undergone complex process conditions such as multiple grinding, high temperature cycles, long reaction times, and multi-step purification, the introduced CsBr, AgBr, and BiBr 3 The powder is not completely reacted, resulting in impurity phases, which reduces the purity of the crystal. Similarly, the literature "Bandgaps of the lead-free halide double perovskites Cs 2 BiAgCl 6 and Cs 2 BnB 6 from theory and experiment” [4] In the solid state reaction under vacuum conditions, CsBr, AgBr and BiBr 3 The powder was sealed in a quartz ampoule, heated to 500°C for 5 hours, and reacted at this temperature for 4 hours to induce spontaneous reaction of the reactants, obtaining millimeter-scale high-purity Cs 2 AG 6 However, the harsh reaction conditions are not conducive to the large-scale preparation of Cs 2 AG 6 crystal, which will increase the preparation cost. In addition, the literature "Pulsed laser deposition of Cs 2 AG 6 :from mechanochemically synthesized powders to dry, single-step deposition” [5] The step-by-step mechanical grinding method for preparing Cs2 AG 6 The crystal method cannot ensure that the reactants and intermediates react fully, and it is easy to 2 AG 6 Therefore, it is urgent to develop a simple process for preparing high-yield and high-purity Cs 2 AG 6 A new approach to crystals.

[0004] References:

[0005] 1.SlavneyAH,Hu T,LindenbergAM,et al.Abismuth-halide double perovskite with long carrier recombination lifetime for photovoltaic applications[J].Journal of the American chemical society,2016,138(7):2138-2141.

[0006] 2.Gao W, Ran C, Xi J, et al. High-quality Cs 2 AG 6 double perovskitefilm for lead-free inverted planar heterojunction solar cells with 2.2% efficiency[J]. ChemPhysChem, 2018, 19(14):1696-1700.

[0007] 3.McClure ET, Ball MR, Windl W, et al.Cs 2 XT 6 (X=Br,Cl):new visiblelight absorbing,lead-free halide perovskite semiconductors[J].ChemistryofMaterials,2016,28(5):1348-1354.4.Filip MR,Hillman S,Haghighirad AA,etal.Band gaps of the lead-free halide double perovskites Cs 2BiAgCl 6 andCs 2 BnB 6 from theory and experiment[J].The journal of physical chemistry letters,2016,7(13):2579-2585.

[0008] 5.Rodkey N, Kaal S, Sebastian-Luna P, et al.Pulsed laser deposition ofCs 2 AG 6 :frommechanochemically synthesized powders to dry,single-stepdeposition[J].Chemistry ofMaterials,2021,33(18):7417-7422. Summary of the invention

[0009] Based on the above existing technologies, the synthesis of Cs 2 AG 6 The present invention aims to provide a high-yield and high-purity Cs 2 AG 6 A room temperature method for preparing polycrystalline powders has the advantages of simple reaction conditions, convenient operation, low requirements for process equipment, and high product purity and yield.

[0010] In order to achieve the above object, the present invention adopts the following technical scheme:

[0011] The high-yield and high-purity Cs 2 AG 6 The room temperature preparation method of polycrystalline powder is realized by room temperature solution method. The specific steps are as follows: CsBr powder, AgBr powder and BiBr 3 After the powders are mixed, DMSO and anti-solvent are added and the reaction is stirred at room temperature. After the reaction is completed, the reaction product is washed, purified, and heated and dried to obtain Cs 2 AG 6 Polycrystalline powder.

[0012] Preferably, CsBr powder, AgBr powder and BiBr 3 The molar ratio of the powder is 2-2.5:1:1-1.5.

[0013] Preferably, the volume ratio of DMSO to anti-solvent is 10% to 90%: 90% to 10%.

[0014] Preferably, CsBr powder, AgBr powder and BiBr 3 The ratio of the total mass of the powder to the total volume of DMSO and anti-solvent is 0.20 to 1 g:1 mL.

[0015] Preferably, the anti-solvent is acetonitrile or dimercaptoethanol.

[0016] Preferably, the stirring reaction time at room temperature is 0.5 to 12 hours.

[0017] Preferably, the solvent used for the cleaning and purification is one that cannot destroy Cs 2 AG 6 Crystal structure and ability to dissolve CsBr and BiBr 3 solvents, such as methanol, ethanol, etc.

[0018] Preferably, the heating and drying temperature is 30-120°C.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. Preparation of Cs by wet chemical method 2 AG 6 When crystallizing, the solubility of AgBr and the presence of impurity phases are key factors affecting the performance of the product. Therefore, the present invention first starts with the solvent and selects a solvent with a large donor number (D N ) of DMSO and anti-solvent (acetonitrile or dithioethanol) to improve the solubility of AgBr and adjust the Cs 2 AG 6 The crystallization process can achieve high yield and high crystallinity of Cs 2 AG 6 Preparation of polycrystalline powders.

[0021] 2. In CsBr, BiBr 3 Add DMSO and anti-solvent (acetonitrile or dithioethanol) to the mixed reaction of AgBr and CsBr. 3 First, Cs is dissolved and ionized + 、Bi 3+ and Br - , where Br - It will interact with AgBr and promote the dissolution of AgBr to form Cs 2 AG 6 The presence of antisolvent in the precursor solution can promote the 2AG 6 Rapid crystallization, producing a large amount of Cs 2 AG 6 Polycrystalline powder, thus achieving high crystallinity and high yield Cs at room temperature 2 AG 6 Preparation of polycrystalline powders.

[0022] 3. Compared with DMSO and acetonitrile, DMSO and dimercaptoethanol can better regulate Cs 2 AG 6 The crystallization process increases Cs 2 AG 6 of crystal quality.

[0023] 4. By increasing the CsBr or BiBr in the reactants 3 The ratio of Br in the precursor solution - The ion concentration promotes the excess bromide ions in the precursor solution to form a complex with AgBr, which helps to further improve the solubility of AgBr and promote the reaction of AgBr with CsBr and BiBr 3 Full reaction, elimination of Cs 3 Bi 2 Br 9 impurities, thereby further increasing Cs 2 AG 6 Purity of polycrystalline powder.

[0024] 5. The present invention prepares Cs with a purity of nearly 100% and a yield of 92% through a simple process at room temperature. 2 AG 6 Polycrystalline powder, high quality Cs for thermal evaporation, sputtering, pulsed laser deposition 2 AG 6 The film provides the source material, further promoting the Cs 2 AG 6 Applications in solar cells, photodetectors and laser diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Cs prepared in Example 4 2 AG 6 Photo of polycrystalline powder.

[0026] Figure 2 Cs prepared in Examples 1 to 5 2 AG 6 XRD pattern of polycrystalline powder. DETAILED DESCRIPTION

[0027] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent claims of the present invention.

[0028] Example 1

[0029] In this example, Cs was prepared according to the following steps 2 AG 6 Polycrystalline powder:

[0030] Weigh CsBr (0.2128 g, 1 mmol), AgBr (0.094 g, 0.5 mmol) and BiBr 3 (0.2243 g, 0.5 mmol) was mixed, 0.3 mL DMSO and 0.7 mL acetonitrile were added, and the mixture was stirred at room temperature for 12 h. After the reaction was completed, the reaction product was washed with methanol by shaking, and the target product was collected and placed in an oven at 50 ° C for 12 h to obtain Cs 2 AG 6 Polycrystalline powder, yield 88.3%.

[0031] The Cs prepared in this example 2 AG 6 The XRD pattern of polycrystalline powder is as follows Figure 2 As shown, it can be seen that the product contains more AgBr and Cs 3 Bi 2 Br 9 Impurity phase, product purity 99.3%.

[0032] Example 2

[0033] In this example, Cs was prepared according to the following steps 2 AG 6 Polycrystalline powder:

[0034] Weigh CsBr (0.2128 g, 1 mmol), AgBr (0.094 g, 0.5 mmol) and BiBr 3 (0.2243 g, 0.5 mmol) was mixed, 0.3 mL DMSO and 0.7 mL 2-mercaptoethanol were added, and the mixture was stirred at room temperature for 8 h. After the reaction was completed, the reaction product was washed with methanol by shaking, and the target product was collected and placed in an oven at 50 ° C for 12 h to obtain Cs 2 AG 6 Polycrystalline powder, yield 90.1%.

[0035] The Cs prepared in this example 2 AG 6The XRD pattern of polycrystalline powder is as follows Figure 2 As shown in the figure, it can be seen that compared with Example 1, since the thiol group in the 2-mercaptoethanol molecule can interact with AgBr, AgBr is fully reacted, and the obtained Cs 2 AG 6 Polycrystalline powder contains only a very small amount of AgBr and Cs 3 Bi 2 Br 9 Impurity phase, product purity 99.6%.

[0036] Example 3

[0037] In this example, Cs was prepared according to the following steps 2 AG 6 Polycrystalline powder:

[0038] Weigh CsBr (0.2128 mg, 1 mmol), AgBr (0.094 g, 0.5 mmol) and BiBr 3 (0.2355 g, 0.525 mmol) was mixed, 0.3 mL DMSO and 0.7 mL acetonitrile were added, and the mixture was stirred at room temperature for 12 h. After the reaction was completed, the reaction product was washed with methanol by shaking, and the target product was collected and placed in an oven at 50 ° C for 12 h to obtain Cs 2 AG 6 Polycrystalline powder with a yield of 88.6%.

[0039] The Cs prepared in this example 2 AG 6 The XRD pattern of polycrystalline powder is as follows Figure 2 As shown in the figure, it can be seen that there is no impurity phase in the product and the product purity reaches 100%. 3 Can provide a certain amount of Br - ions combine with AgBr to form a complex, which inhibits Cs 3 Bi 2 Br 9 and the formation of AgBr.

[0040] Example 4

[0041] In this example, Cs was prepared according to the following steps 2 AG 6 Polycrystalline powder:

[0042] Weigh CsBr (0.2128 mg, 1 mmol), AgBr (0.094 g, 0.5 mmol) and BiBr 3(0.2355 g, 0.525 mmol) was mixed, 0.3 mL DMSO and 0.7 mL 2-mercaptoethanol were added, and the mixture was stirred at room temperature for 8 h. After the reaction was completed, the reaction product was washed with methanol by shaking, and the target product was collected and placed in an oven at 50 ° C for 12 h to obtain Cs 2 AG 6 Polycrystalline powder (such as Figure 1 The yield was 92%.

[0043] The Cs prepared in this example 2 AG 6 XRD of polycrystalline powder Figure 2 As shown, similar to Example 3, in this example, BiBr 3 Under the condition of excess of 5 mmol%, there is no impurity phase in the product, and the product purity reaches 100%. Compared with Example 3, the product of this example has a higher crystallinity, indicating that DMSO and dimercaptoethanol can better regulate Cs 2 AG 6 The crystallization process can produce Cs 2 AG 6 Polycrystalline powder.

[0044] Example 5

[0045] Weigh CsBr (0.2234 mg, 1.05 mmol), AgBr (0.094 g, 0.525 mmol) and BiBr 3 (0.2243 g, 0.5 mmol) was mixed, 0.3 mL DMSO and 0.7 mL 2-mercaptoethanol were added, and the mixture was stirred at room temperature for 8 h. After the reaction was completed, the reaction product was washed with methanol by shaking, and the target product was collected and placed in an oven at 50 ° C for 12 h to obtain Cs 2 AG 6 Polycrystalline powder with a yield of 89.9%.

[0046] The Cs prepared in this example 2 AG 6 XRD of polycrystalline powder Figure 2 As shown, it can be seen that there is no impurity phase in the product and the product purity reaches 100%. It can be seen that 5 mol% excess CsBr can provide a certain amount of Br - ions combine with AgBr to form a complex, thereby completely suppressing the impurity phase Cs 3 Bi 2 Br 9 However, the crystallinity of the product obtained when CsBr is excessive in this example is lower than that of BiBr in Example 4.3 The crystallinity of the product obtained when the amount is excessive.

[0047] The above description is only an exemplary embodiment of the present invention and does not limit the present invention in any way. Any modification and equivalent changes made according to the method of the present invention still fall within the scope of protection of the present invention.

Claims

1. A room temperature method for preparing high-yield and high-purity Cs2AgBiBr6 polycrystalline powder, characterized in that: After mixing CsBr powder, AgBr powder and BiBr3 powder, DMSO and anti-solvent are added, and the reaction is stirred at room temperature. After the reaction is completed, the reaction product is cleaned, purified, and heated and dried to obtain Cs2AgBiBr6 polycrystalline powder.

2. The room temperature preparation method according to claim 1, characterized in that: The molar ratio of CsBr powder, AgBr powder and BiBr3 powder is 2-2.5:1:1-1.

5.

3. The room temperature preparation method according to claim 1, characterized in that: The volume ratio of DMSO to anti-solvent is 10% to 90%: 90% to 10%.

4. The room temperature preparation method according to claim 1, characterized in that: The ratio of the total mass of CsBr powder, AgBr powder and BiBr3 powder to the total volume of DMSO and anti-solvent is 0.20-1 g:1 mL.

5. The room temperature preparation method according to claim 1, characterized in that: The anti-solvent is acetonitrile or dimercaptoethanol.

6. The room temperature preparation method according to claim 1, characterized in that: The reaction time is 0.5 to 12 hours under stirring at room temperature.

7. The room temperature preparation method according to claim 1, characterized in that: The solvent used for the cleaning and purification is methanol or ethanol.

8. The room temperature preparation method according to claim 1, characterized in that: The heating and drying temperature is 30-120°C.

9. A Cs2AgBiBr6 polycrystalline powder obtained by the preparation method described in any one of claims 1 to 8.

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