Preparation And Study Of Bismuth Antimony Oxyhalide Quantum Dots

Colloidal quantum dots(QDs)have attracted wide attention due to their tunable size and tunable electronic energy band.However,in the pursuit of improving device performance and application effect,researchers should also take into account the impact of materials on environmental pollution and human safety.At this stage,more mature quantum dots mainly contain strong carcinogenic heavy metal Cd or toxic heavy metal Pb,which has been greatly limited in the application of quantum dots.In order to promote the development of quantum dots in the future and expand the scope of application,it is necessary to study green,low-cost and high-performance fluorescent quantum dots.Compared with the most studied II–VI semiconductor nanomaterials such as Cd S and III–V semiconductor nanomaterials such as In P,the two kinds of semiconductor quantum dots,bismuth halooxy and antimony iodoxy synthesized in this paper,still show excellent luminescence performance and good stability without core-shell structure.Therefore,bismuth-and antimony-based quantum dots have great potential as luminescent materials.In this paper,the synthesis route,preparation conditions,performance optimization,lighting application and other aspects are studied,the specific research content is as follows:1.Bismuth oxyhalide(BiOX,X=Cl,Br/Cl,Br,Br/I,I)quantum dots with good stability were synthesized by high temperature injection method.The size range of nanocrystals is 3-10 nm.The energy band of quantum dots can be adjusted effectively by changing the composition of quantum dots while keeping the size of quantum dots unchanged.The emission wavelength(445 nm-549 nm)and luminescence color(blue-yellow)can be tuned by the size of quantum dots or the type and proportion of halides(Cl,Br/Cl,Br,Br/I,I).White light emitting diode(WLED)was fabricated by combining yellow Bi OI quantum dots with 50 lm·W^-1 blue LED chip.2.Antimony iodoxy quantum dots with blue emission were prepared by high temperature injection method without inert gas protection.The prepared material has uniform size distribution(about 10 nm)and good dispersion.Under 365 nm UV excitation,the typical sample exhibits blue emission with the main peak at near 445 nm.The luminescence properties of synthesized quantum dots under different temperature,time and raw material ratio were investigated.The tunable emission wavelength position(445 nm-551 nm),color(blue to yellow-green)and band gap(2.61 e V-4.09 e V)of antimony iodoxy quantum dots are obtained by changing the raw material ratio.The luminescence characteristics of antimony iodooxide QDS were optimized by adding different proportions of Zn²⁺.The photoluminescence spectrum is blue shifted,and the spectral intensity increases.