METHOD FOR OBTAINING SUPERLATTICES FROM LEAD-HALIDE PEROVSKITE NANOCRYSTALS Russian patent published in 2022 - IPC C30B29/68 C30B29/12 C09K11/54 C09K11/55 C09K11/61 C09K11/66 B82B3/00 B82Y20/00 B82Y40/00 

FIELD: superlattices production.

SUBSTANCE: invention relates to a technology for producing superlattices from nanocrystals of lead-halide perovskite doped with cadmium ions CsCd_xPb_1-xBr₃, (0<x<1), which can be used as components of optoelectronic devices operating in the blue wavelength range.

The method for producing superlattices from nanocrystals of lead halide perovskite includes adding octadecene to anhydrous cesium carbonate Cs₂CO₃powder, keeping the resulting mixture at a temperature of 100°C for 30 min, adding oleic acid and heating to 180°C to form cesium oleate, cooling the resulting solution to 25°C for 30 min, introducing octadecene into lead bromide PbBr₂, creating a vacuum, followed by stirring at 100°C for 30 min, introducing oleylamine and oleic acid into this mixture and heating it to 180°C, mixing the resulting solutions of cesium oleate and lead bromide to form a colloidal solution of nanocrystals of lead-halide perovskite in octadecene, cooling it to 15°C in an ice bath, purification from octadecene by centrifugation , redispersing the nanocrystal precipitate, re-centrifuging the colloidal solution and removing the supernatant solution, redispersing the nanocrystal precipitate in toluene to form a colloidal solution of lead-halide perovskite nanocrystals in toluene, which is instilled onto a preliminarily cleaned silicon substrate with the formation of superlattices from nanocrystals of lead-halide perovskite upon evaporation of toluene, while before cleaning, octadecene is additionally added into a colloidal solution of nanocrystals of lead-halide perovskite CsPbBr₃ in octadecene, centrifugation during cleaning is carried out with an acceleration of 1000 g for 5 -10 min, then the supernatant solution is removed, the redispersion of the precipitate of nanocrystals is carried out in octadecene, a pre-prepared mixture is added to it, obtained by mixing cadmium bromide tetrahydrate CdBr₂•4H₂O with octadecene at a temperature of 130°C at a speed of 1000 rpm in a glove box filled with a nitrogen atmosphere of 99.999% for 40 min and adding oleylamine and oleic acid with heating to 180°C and cooling to 25°C in 30 min, the resulting composition is evacuated and stirred at a speed of 1000 rpm at room temperature for 10 min, heated to 150°C and kept for 10 min, cooled to 25°C for 30 s, resulting in a colloidal solution of nanocrystals of composition CsCd_xPb_1-xBr₃, (0<x<1) in octadecene, repeated centrifugation is carried out with an acceleration of 1000g for 5 min, and after removal of the supernatant solution, as a result of the redispersion of the precipitate of nanocrystals in toluene, a concentrated colloidal solution of nanocrystals of lead-halide perovskite CsCd_xPb_1-xBr₃ in toluene is obtained, the solution after redispersion is again centrifuged in toluene with an acceleration of 1000 g for 5 min, and the supernatant colloidal solution of nanocrystals of the composition CsCd_xPb_1-xBr₃ in toluene, which is dropped onto the said silicon substrate, previously cleaned in an oxygen plasma atmosphere at a pressure of 0.3-0.4 Mbar with a generator power of 50-100 W for 1 min. The addition of cadmium to the structure of lead-halide perovskite nanocrystals makes it possible to obtain superlattices from CsCd_xPb _1-x Br₃, (0<x<1), nanocrystals, which provide blue photoluminescence.

EFFECT: reducing the amount of reagents at the stage of cleaning and replacing the acid treatment of substrates with plasma provides optimization of the manufacturing process and its simplification.

1 cl, 1 ex, 3 dwg