Preparation And Properties Of CsPbBr₃ Nanorods And Cs₄PbBr₆/CsPbBr₃ Composites

All-inorganic perovskite nanocrystals?CsPbX₃ NCs,X=Cl,Br,I?appear to be fascinating for next-generation ultrahigh-definition?UHD?displays due to their very high color purity,tunable optical bandgap,and high photoluminescence quantum yields?PLQY?.These excellent optical properties of CsPbX₃ have great application potential in the field of optoelectronic devices,especially low-cost lighting and display.The researchers have developed many synthetic methods,which can be used to synthesize nano-cubes,nano-spheres,nano-wires,nano-plates,nano-sheet morphology.But,the synthesis of CsPbX₃ nanorods is rarely involved in.This is not conducive to the comprehensive development of CsPbX₃ nanocrystals.In addition to morphology,the stability of CsPbX₃ nanocrystals is poor,which also greatly restricts its application prospects.At the same time,the poor stability of CsPbX₃ nanomaterials has greatly hindered its application progress.Based on the above factors,we developed a facile,low-cost and large-scale synthesis of CsPbBr₃ NRs with 86%PLQY at room temperature.And the synthesis method is very simple and suitable for large-scale industrial production.For the stability of CsPbBr₃ nanocrystals,this paper designed a facile and large-scale synthesis method of Cs₄PbBr₆/CsPbBr₃ composites.Compared with CsPbBr₃ nanocrystals,the stability of Cs₄PbBr₆/CsPbBr₃ composites is greatly improved.The main work of this article is as follows:?1?We use innovatively acetic acid as precursor solvent promoted the concentrations of Cs⁺and Pb²⁺in the precursor solution and dominated the formation of CsPbBr₃ NRs.Subsequently,the precursor solvent was injected into the non-polar reaction solvent containing the oleic acid?OA?and oleylamine?OAm?ligands,and HBr as the bromine source in the acetic acid solution at room temperature atmospheric environment.The synthesized CsPbBr₃ NRs with an average width of around 8 nm and average lengths of 18 to 30 nm have an excellent narrow-band?FWHM=17 nm?green emission peaked at 517 nm.?2?A control experiment was designed for this synthesis method,and the effects of each component on the reaction morphology were studied.The following conclusions are drawn:OA and OAm as ligands stabilize the structure of CsPbBr₃nanorods.The precursor solvents acetic acid and OAm dominate the generation of nanorod morphology.According to this conclusion,the type of precursor solvent?acetic acid-octanoic acid?was changed,and CsPbBr₃ nanocrystals with different morphologies and different emission peak positions were obtained.?3?The prepared CsPbBr₃ nanocrystals were converted into CsPbX₃ nanocrystals in each group by anion exchange reaction,and emission spectra covering the entire visible light range?420-680nm?were obtained.A pc-WLED using CsPbBr₃ films and K₂SiF₆:Mn⁴⁺as green-and red-emitting phosphors,respectively,and a blue InGaN chip was packaged.Furthermore,white LEDs prepared with CsPbBr₃ NRs exhibited a high luminous efficiency of 63.14 lm/W and a wide color gamut of 112%NTSC.These results indicate that the CsPbBr₃ prepared by our synthetic method has a good development prospect in-UHD LED displays.?4?A room temperature synthesis method of Cs₄PbBr₆/CsPbBr₃ composite material is designed.The synthesized Cs₄PbBr₆/CsPbBr₃ composite material has CsPbBr₃ as the luminescence center and Cs₄PbBr₆ as the main body.The Cs₄PbBr₆/CsPbBr₃ composite material has an excellent narrow-band?FWHM=23 nm?green emission peaked at 518 nm,and a quantum efficiency of 54%.The composite material has better stability than CsPbBr₃ nanomaterials.