Preparation method of AgBiS2 / perovskite Janus nanocrystalline heterostructure

Abstract

The invention discloses a preparation method of an AgBiS2 / perovskite Janus nanocrystal heterostructure and a preparation method of the AgBiS2 / perovskite Janus nanocrystal heterostructure. Comprising the following steps: S1, preparing a precursor solution A; s2, preparing a precursor solution B; s3, synthesizing a perovskite seed crystal; s4, preparing a precursor solution C, and adding a perovskite seed crystal into the precursor solution C to obtain a precursor solution D; s5, preparing a precursor solution E; and S6, adding the precursor solution E into the precursor solution D to obtain the AgBiS2 / perovskite Janus nanocrystalline heterostructure. Compared with traditional monodisperse AgBiS2 and perovskite quantum dots, the monodisperse AgBiS2 / perovskite quantum dot composite material has significant advantages, combines respective spectral characteristics of AgBiS2 and perovskite quantum dots, successfully expands a spectrum from visible light to a near-infrared region, and greatly improves the utilization rate of the spectrum. The introduction of AgBiS2 not only reduces the harm of heavy metals of perovskite, but also greatly enhances the stability of the overall structure, and the heterojunction can effectively promote the separation and transmission of photon-generated carriers, reduce the electron-hole recombination probability, and significantly improve the efficiency of photoelectric devices.

Description

Technical Field

[0001] The invention relates to the field of nano functional materials and optoelectronic devices, and in particular to a method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure. Background Art

[0002] In today's era of rapid technological development, efficient use of energy and continuous improvement of optoelectronic device performance have become key goals in the field of scientific research. Photocatalysis and photovoltaic technology, as energy conversion pathways with great potential, have always attracted much attention. However, traditional optoelectronic devices face many challenges in practical applications.

[0003] As an emerging optoelectronic material, perovskite quantum dots have excellent optical and electrical properties, but their stability is a big problem. Perovskite materials themselves are sensitive to environmental factors such as water, oxygen and heat, and are prone to adverse changes such as decomposition and phase change. In a humid environment, moisture will react with perovskite, causing its structural destruction; under high temperature conditions, the crystal structure of perovskite may also change, affecting its optoelectronic properties. In addition, perovskite quantum dots are also prone to photodegradation under light irradiation, reducing their service life and stability. These stability issues have greatly limited the further development of perovskite quantum dots in practical applications.

[0004] In order to break through these bottlenecks, researchers are committed to finding new material systems and structures to improve the performance of optoelectronic devices. AgBiS2 has unique spectral characteristics. Combining it with perovskite quantum dots to construct AgBiS2 / perovskite Janus nanocrystal heterostructures has become an extremely innovative research direction. This heterostructure can not only combine the spectral advantages of both, expand the spectrum to the near-infrared region, and improve the utilization of the spectrum, but also flexibly regulate the band structure through compounding, bringing new opportunities for applications in optoelectronic devices and other fields. In addition, the introduction of AgBiS2 greatly enhances the stability of the perovskite structure, effectively solves the problem of poor stability of perovskite quantum dots, and at the same time promotes the separation and transmission of photogenerated carriers, reduces the probability of electron-hole recombination, and opens up a new path for improving the performance of optoelectronic devices. Summary of the invention

[0005] The present invention provides a method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure, and the specific steps are as follows:

[0006] S1: preparing precursor solution A;

[0007] S2: preparing precursor solution B;

[0008] S3: preparing a seed solution C of perovskite;

[0009] S4: preparing precursor solution D;

[0010] S5: preparing precursor solution E;

[0011] S6: Synthesis of AgBiS2 / perovskite Janus nanocrystal heterostructures.

[0012] Furthermore, step S1 is specifically as follows:

[0013] The A salt, the organic ligand and the non-coordinating solvent are fully mixed, raised to a certain temperature T1, and stirred for a predetermined time, thereby successfully obtaining a clear and transparent precursor solution A.

[0014] Furthermore, step S2

[0015] The lead halide is mixed with a non-coordinating solvent, and the temperature is raised to a certain temperature T2 under a certain vacuum degree. Then a certain amount of organic anion ligand and organic cationic ligand are added, and the mixture is heated to a certain temperature T3 and stirred for a certain period of time until the solution becomes clear and transparent, thereby obtaining the precursor solution B.

[0016] Furthermore, step S3

[0017] At temperature T4, a certain amount of precursor solution A is added to precursor solution B, reacted for a certain period of time, and then the solution is quickly cooled to room temperature to obtain a perovskite seed solution C.

[0018] Furthermore, step S4

[0019] The bismuth salt, silver salt, non-coordinating solvent and cationic ligand are fully mixed, heated to a certain temperature T5 under a certain vacuum degree, and stirred for a certain period of time to obtain a clear and transparent precursor solution D.

[0020] Furthermore, step S5

[0021] A certain amount of perovskite seed solution C is added to the precursor solution D and stirred for a certain period of time to obtain the precursor solution E.

[0022] Furthermore, step S6

[0023] Add the sulfur source and ligand to the non-coordinating solvent, stir for a certain period of time at temperature T6 to obtain a clear and transparent precursor solution F; then add a certain amount of precursor solution F to precursor solution E, react for a certain period of time at temperature T7 to obtain AgBiS2 / perovskite Janus nanocrystal heterostructure.

[0024] Further, in step S1,

[0025] Salt A is one or more of cesium carbonate, dicesium hydrogen phosphate, cesium hydrogen carbonate, cesium vanadate, cesium oxalate, cesium chromate, cesium permanganate, cesium dichromate, cesium borate, cesium silicate, cesium sulfite, cesium tungstate, cesium molybdate, cesium dihydrogen phosphate, cesium oleate, cesium propionate, cesium butyrate, cesium citrate, cesium sulfate and cesium tartrate; the organic ligand is one or more of octanoic acid, oleic acid, stearic acid, capric acid and trioctylphosphine oxide. The non-coordinating solvent is octadecene. The temperature T1 is 50-150°C; the stirring time is 60-120min; the stirring speed is 300-1200rpm. The concentration of precursor solution A is 0.0008-0.7235g / mL.

[0026] Further, in step S2,

[0027] The lead halide is one or more of lead bromide, lead iodide, lead chloride and lead fluoride; the non-coordinating solvent is one or more of octadecene, octane and dodecane; the organic cationic ligand is one or more of oleic acid, stearic acid, oxalic acid, mercaptopropionic acid, dodecanethiol, thioglycolic acid, undecylenic acid, octanoic acid and trioctylphosphine oxide; the organic anionic ligand may be but is not limited to one or more of oleylamine, dodecylamine, hexadecylamine, trioctylamine, tributylamine and octylamine; the vacuum degree is 0.6-90 Pa, the temperature T2 is 80-140° C.; the temperature T3 is 170-200° C. and the stirring time is 30-150 min.

[0028] The volume ratio of the organic anion ligand to the organic cation ligand is 0.2-1.5:1, and the volume ratio of the organic anion ligand to the non-coordinating solvent is 0.05-1.8:1; the concentration of the precursor solution B is 0.0015-0.8732 g / mL.

[0029] Further, in step S3,

[0030] The volume ratio of precursor solution B to precursor solution A is 0.13-2.15:1; the reaction time is 10-150s; and the T4 temperature is 70-180°C.

[0031] Further, in step S4,

[0032] The silver salt is one or more of silver acetate, silver oxalate, silver stearate, silver carbonate, silver nitrate, silver thiocyanate, silver bromide, silver oxide, silver iodide, silver chloride and silver fluoride; the bismuth salt is one or more of bismuth acetate, bismuth sulfate, bismuth laurate, bismuth neodecanoate, bismuth cyclopentaneate, bismuth oxide, bismuth methanesulfonate, bismuth carbonate, bismuth nitrate, bismuth halide, bismuth thiocyanate and bismuth oxalate; the cationic ligand is one or more of oleic acid, octanoic acid, capric acid, trioctylphosphine oxide, diphenylphosphine oxide and tributylphosphine; the non-coordinating solvent is one or more of octadecene, octane and dodecane; the vacuum degree is 0.2-50 Pa; the temperature T5 is 80-200° C., the stirring time is 1-3 hours, the stirring speed is 400-800 rpm, and the concentration of the precursor solution D is 0.0084-0.5743 g / mL.

[0033] Further, in step S5,

[0034] The volume ratio of the precursor solution D to the perovskite seed solution C is 0.6-4:1; the stirring time is 10s-200min.

[0035] Further, in step S6,

[0036] The sulfur source is one or more of sulfur powder, hexamethyldisilathione, mercaptan, thioacetamide, and carbon disulfide; the ligand is one or more of trioctylphosphine, oleic acid, octanoic acid, and oleylamine; the non-coordinating solvent is octadecene; the T6 temperature is room temperature to 200°C, and the stirring time is 0-120min; the T7 temperature is room temperature to 120°C, the volume ratio of the precursor solution F to the precursor solution E is 0.2 to 0.8:1; and the reaction time is 10 to 200min.

[0037] Compared with the prior art, this patent application has the following beneficial effects:

[0038] AgBiS2 / perovskite Janus nanocrystal heterostructure has significant advantages over traditional monodisperse AgBiS2 and perovskite quantum dots. It combines the spectral characteristics of AgBiS2 and perovskite quantum dots, successfully expands the spectrum from visible light to the near-infrared region, and greatly improves the utilization rate of the spectrum. At the same time, the band structure can be flexibly controlled through the combination of the two, and it has great application potential in the field of optoelectronic devices. Furthermore, in view of the poor stability of perovskite nano-quantum dots, the introduction of AgBiS2 greatly enhances the overall structural stability, and its stability under specific environmental conditions is greatly improved compared to pure perovskite nanocrystals. What is particularly critical is that the heterojunction can effectively promote the separation and transmission of photogenerated carriers, reduce the probability of electron-hole recombination, significantly improve the efficiency of optoelectronic devices, and bring major breakthroughs in the performance improvement of optoelectronic devices. It has extremely high application value and broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A transmission electron microscope morphology image of a CsPbBr3 seed crystal in a method for preparing a AgBiS2 / perovskite Janus nanocrystal heterostructure according to the present invention;

[0040] Figure 2 A transmission electron microscope morphology image of an AgBiS2 / CsPbBr3 nanocrystal heterostructure in a method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure according to the present invention;

[0041] Figure 3 A high-resolution transmission electron microscope morphology image of an AgBiS2 / CsPbBr3 nanocrystal heterostructure in a method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure according to the present invention;

[0042] Figure 4 A fluorescence image of a AgBiS2 / CsPbBr3 heterostructure in a method for preparing a AgBiS2 / perovskite Janus nanocrystal heterostructure according to the present invention;

[0043] Figure 5 It is an absorption diagram of the AgBiS2 / CsPbBr3 nanocrystal heterostructure in the preparation method of the AgBiS2 / perovskite Janus nanocrystal heterostructure according to the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0045] Example 1

[0046] A method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure comprises the following steps:

[0047] S1: preparing precursor solution A;

[0048] 0.4 g of cesium carbonate, 1.5 mL of oleic acid, 1.2 mL of octanoic acid and 15 mL of octadecene were fully mixed, heated to 130°C, stirred for 90 min at a stirring speed of 500 rpm, and a clear and transparent precursor solution A with a concentration of 0.0225 g / mL was obtained;

[0049] S2: Preparation of precursor solution B

[0050] 0.138 g of lead bromide and 10 mL of octadecene were mixed, vacuumed to 20 Pa, heated to 120° C., and then 1.5 mL of oleic acid and 1.5 mL of oleylamine were added to the mixed solution, and then the temperature was raised to 170° C. and stirred at this temperature for 30 min to obtain a clear and transparent precursor solution B with a concentration of 0.0106 g / mL;

[0051] S3: Preparation of perovskite seed solution C

[0052] At 140°C, 0.9 mL of precursor solution A was added to the prepared precursor solution B, and the reaction was continued for 45 seconds. The solution was then quickly cooled to room temperature to obtain a perovskite seed solution C.

[0053] Through TEM characterization of CsPbBr3 seeds, it was found that the morphology of CsPbBr3 seeds was spherical particles with a size of about 6-8nm ( Figure 1 );

[0054] S4: Preparation of precursor solution D

[0055] 1.5444 g of bismuth acetate, 0.5341 g of silver acetate, 15 mL of octadecene and 24 mL of oleic acid were fully mixed, heated to 100° C. under a vacuum of 10 Pa, and then stirred at this temperature at a rotation speed of 500 rpm for 2 hours to obtain a clear and transparent precursor solution D with a concentration of 0.0532 g / mL.

[0056] S5: Preparation of precursor solution E

[0057] 4 mL of perovskite seed solution C was added to the precursor solution D prepared in S4 and stirred for 30 min to obtain precursor solution E;

[0058] S6: Synthesis of Janus Nanocrystal Heterostructures of AgBiS2 / CsPbBr3

[0059] 0.8 mL of hexamethyldisilathane and 0.2 mL of oleylamine were added to 5 mL of octadecene, and then stirred at room temperature for 20 min to obtain a clear and transparent precursor solution F; then the obtained precursor solution F was completely injected into the precursor solution E, and the reaction was carried out at 100°C for 10 min to obtain the Janus nanocrystalline heterostructure of AgBiS2 / CsPbBr3.

[0060] Through TEM characterization, it was found that the morphology of the sample was Janus heterostructure ( Figure 2-3 ), indicating that we have successfully synthesized AgBiS2 / CsPbBr3. Through fluorescence spectroscopy characterization, it was found that the fluorescence peak of AgBiS2 / CsPbBr3 was 513nm and the half-peak width was 18nm ( Figure 4 ), demonstrating that the Janus nanocrystal heterostructure of AgBiS2 / CsPbBr3 can be used as an excellent optoelectronic material, with an absorption peak at 509nm ( Figure 5 ).

[0061] Example 2

[0062] A method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure comprises the following steps:

[0063] S1: preparing precursor solution A;

[0064] 0.4 g of cesium carbonate, 1.5 mL of oleic acid, 1.2 mL of octanoic acid and 15 mL of octadecene were fully mixed, and stirred at 130°C for 90 min at a stirring speed of 500 rpm to obtain a clear and transparent precursor solution A with a concentration of 0.0225 g / mL;

[0065] S2: Preparation of precursor solution B

[0066] 0.105 lead chloride and 10 mL octadecene were mixed, vacuumed to 30 Pa, heated to 120°C, and then 1.5 mL oleic acid, 1.5 mL oleylamine and 2 mL trioctylphosphine were added to the mixed solution, and then the temperature was raised to 200°C and stirred at this temperature for 30 min to obtain a clear and transparent precursor solution B with a concentration of 0.0070 g / mL;

[0067] S3: Preparation of perovskite seed solution C

[0068] At 180°C, 0.9 mL of cesium precursor solution was added to the prepared precursor solution B, and the reaction was continued for 45 seconds, and then the solution was quickly cooled to room temperature to obtain a seed solution C of CsPbCl3 perovskite;

[0069] S4: Preparation of precursor solution D

[0070] 1.5444 g of bismuth acetate, 0.5341 g of silver acetate, 15 mL of octadecene and 24 mL of oleic acid were fully mixed, heated to 100° C. under a vacuum of 6 Pa, and then stirred at this temperature at a rotation speed of 500 rpm for 2 hours to obtain a clear and transparent precursor solution D with a concentration of 0.0532 g / mL.

[0071] S5: Preparation of precursor solution E

[0072] 4 mL of perovskite seed solution C was added to the precursor solution D prepared in S4 and stirred for 60 min to obtain precursor solution E;

[0073] S6: Synthesis of Janus Nanocrystalline Heterostructures of AgBiS2 / CsPbCl3

[0074] 0.8 mL of hexamethyldisilathane and 0.2 mL of oleylamine were added to 5 mL of octadecene, and then stirred at 50°C for 30 minutes to obtain a clear and transparent precursor solution F; then the obtained precursor solution F was completely injected into the precursor solution E, and the reaction was carried out at 110°C for 15 minutes to obtain the Janus nanocrystalline heterostructure of AgBiS2 / CsPbCl3.

[0075] Example 3

[0076] A method for preparing an AgBiS2 / perovskite Janus nanocrystal heterostructure comprises the following steps:

[0077] S1: preparing precursor solution A;

[0078] 0.4 g of cesium carbonate, 1.5 mL of oleic acid, 1.2 mL of octanoic acid and 15 mL of octadecene were fully mixed, and stirred at 130°C for 90 min at a stirring speed of 500 rpm to obtain a clear and transparent cesium precursor solution A with a concentration of 0.0225 g / mL;

[0079] S2: Preparation of precursor solution B

[0080] 0.173 g of lead iodide was mixed with 10 mL of octadecene, and the mixture was evacuated to 25 Pa and heated to 120° C. Then 1.0 mL of oleic acid and 1.0 mL of oleylamine were added to the mixed solution, and the temperature was subsequently raised to 170° C. and stirred at this temperature for 60 min to obtain a clear and transparent precursor solution B with a concentration of 0.0133 g / mL.

[0081] S3: Preparation of perovskite seed solution C

[0082] At 180°C, 0.9 mL of cesium precursor solution was added to the prepared precursor solution B, and the reaction was continued for 45 seconds, and then the solution was quickly cooled to room temperature to obtain CsPbI3 perovskite seed solution C;

[0083] S4: Preparation of precursor solution D

[0084] 1.5444 g of bismuth acetate, 0.5341 g of silver acetate, 15 mL of octadecene and 24 mL of oleic acid were fully mixed, heated to 100° C. under a vacuum of 7 Pa, and then stirred at this temperature at a speed of 500 rpm for 2 hours to obtain a clear and transparent precursor solution D with a concentration of 0.0532 g / mL;

[0085] S5: Preparation of precursor solution E

[0086] 3 mL of perovskite seed solution C was added to the precursor solution D prepared in S4 and stirred for 100 min to obtain precursor solution E;

[0087] S6: Synthesis of Janus Nanocrystalline Heterostructures of AgBiS2 / CsPbI3

[0088] 0.128 g of sulfur powder and 5 mL of trioctylphosphine were added to 5 mL of octadecene, and then stirred at 120°C for 80 min to obtain a clear and transparent precursor solution F; then the obtained precursor solution F was completely injected into the precursor solution E, and the reaction was carried out at 100°C for 30 min to obtain the Janus nanocrystalline heterostructure of AgBiS2 / CsPbI3.

Claims

1. A method for preparing AgBiS2 / perovskite Janus nanocrystal heterostructure, characterized in that: The specific steps are as follows: S1: preparing precursor solution A; S2: preparing precursor solution B; S3: preparing a seed solution C of perovskite; S4: preparing precursor solution D; S5: preparing precursor solution E; S6: Synthesis of AgBiS2 / perovskite Janus nanocrystal heterostructures.

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