Study On Novel Synthesis Of New Perovskte Quantum Dots And Their Stability Enhanced By Nano Boron Nitride

Human society cannot work without light,researches on novel light emitting materials never stoped.New inoraganic perovskite quantum dots?IPQDs?come as a novel kind of luminescence materials into people's horizons.IPQDs has many advantages,such as:low cost,high efficiency of light absorption,high carrier mobility,narrow full-width-at-half-maximums?FWHM?and broad photoluminescence?PL?wavelength.The IPQDs are very potential of a new generation of light-emitting materials.Outstanding properties make them perfect candidate in applications of biological fluorescent tags,solar panels,LED display and other potential applications.However,IPQDs materials have the shortcoming of insufficient stability,which seriously restrict their further development and application.In this paper,we use laser irradiation synthesis method to synthesize IPQDs successfully.Boron nitride,with high chemistry stability,wave permeability and high thermal conductivity properties,is used to combine with IPQDs to improve its stability.The contents are as follows:?1?Full spectrum of IPQDs are synthesized in the solution using a new type of laser irradiation synthesis method.Continuous laser is used as a heating source to synthesize without a protective atmosphere in solution.As prepared IPQDs samples of blue,green and red color are CsPbCl_1.5Br_1.5,CsPbBr₃ and CsPbBr_0.75I_2.25.25 respectively.The luminescence peak positions are divided into 460 nm,514 nm and 653 nm,and photoluminescence peaks of half high width are 14 nm,15 nm and 38 nm.Quantum efficiency are 40%,92%and77%.The instantaneous high energy effect of laser can make IPQDs rapid prototyping in short time.Ensure that the quantum dots are successfully synthesized,while greatly reducing the time needed.This made the IPQDs smaller size and more regular structure.The laser synthesized IPQDs material is a kind of extremely potential luminescent material with excellent luminous performance.?2?As the high chemical stability and transmittance characteristics of boron nitride,it is used to combind with the IPQDs to improve their stability.There is no obvious shift or change of the luminescence peak position.The fluorescence lifetime and quantum efficiency of the composite BN-IPQDs samples have some changes.The fluorescence lifetime of BNNP-CsPbBr₃ and BNNP-CsPbBr_0.75I_2.25.25 are 12.2 ns and 15.8 ns,respectively,and the quantum efficiency are 81%and 62%respectively,minute decreased than before.For the transient PL luminescence data,the luminescence performance of the composite samples attenuates a little,but the stability of the composite IPQDs luminescence materials are greatly improved.After 96 h ultraviolet radiation test,the PL intensity of the exposed IPQDs is only 40%,while the composite sample can still reach 80%of the original luminous intensity.In the temperature stability test,after high temperature treatment at90?,the composite BNNP-CsPbBr₃ sample still remain 50%PL intensity while the exposed IPQDs samples almost lost their luminescent properties.What's more interesting is that the BNNP-CsPbBr_0.75I_2.25.25 sample can still give bright orange light after placed in a non shading natural environment for 80 days.Translucent wave characteristics ensure that the IPQDs in the hole can still have photoluminescent behaviour,and the high chemical stability of BN can protect the IPQDs to avoid the excessive contact with the external environment.