Infrared Luminescence Properties And Energy Transfer Mechanism Of Highly Stable Lead-free Rare Earth Perovskite Fluoride Glass

In recent years,perovskite quantum dots have attracted extensive attention of researchers because of their excellent photoelectric properties.They have many application prospects in light-emitting diodes,lasers,solar cells,infrared detectors and photoelectric detection manufacturing technology.Nevertheless,the toxicity of lead and the instability of perovskite still limit the large-scale development of the commercialization of perovskite quantum dots.At present,the luminescence research of perovskite is mainly concentrated in the visible region,the research in the mid infrared region is less.But mid infrared laser materials have broad application prospects in the fields of biological research,medical treatment,environmental monitoring and material processing,and have always been the key research fields of laser workers at home and abroad.Research shows that more than 90%of laser materials are related to rare earth ions.Rare earth ion doped fluoride glass has good transmittance and low phonon energy.It is an ideal material for mid infrared lasers.Cs₃Bi_2-yEr_yBr₉perovskite was prepared in this paper.Due to its poor stability and serious thermal effect under laser pumping,Cs₃Bi_2-yEr_yBr₉perovskite fluoride glasses were prepared.Their visible properties under 380 nm light excitation and infrared luminescence properties under 980 nm light excitation were studied.Research shows that some Er³⁺ions are located in the glass matrix,part of Er³⁺ions replace Bi³⁺in Cs₃Bi₂Br₉to bond with Br^-.The symmetry of local crystal field is reduced,the up conversion and mid infrared luminescence are enhanced.In addition,the stability can be effectively improved by implanting perovskite into glass matrix.Cs₃Bi_2-yHo_yBr₉perovskite was prepared in this paper.In order to improve its stability,Cs₃Bi_2-yHo_yBr₉perovskite glass was prepared by melt quenching and heat treatment.There is an energy transfer process between Bi³⁺and Ho³⁺,which effectively enhances the infrared luminescence.The oscillator strength parameters were calculated by absorption spectrum and J-O theory,the results showed that the covalency and asymmetry around Ho³⁺in Cs₃Bi_2-yHo_yBr₉perovskite glass were improved.Cs₃Bi_2-yHo_yBr₉perovskite glass is an attractive mid infrared laser material.Cs₃Bi_2-m-nEr_mDy_nBr₉perovskite was prepared in this paper.In order to improve the stability of perovskite,Cs₃Bi_2-m-nEr_mDy_nBr₉was coated with glass matrix.A series of material characterization were carried out.There was energy transfer between Er³⁺ions and Dy³⁺ions in the case of co-doping.The 2.7μm emission of Er³⁺and 2.85-3.1μm emission of Dy³⁺were superimposed to produce a 3μm wide spectrum emission.Cs₃Bi_2-m-nEr_mDy_nBr₉perovskite glass has low phonon energy,this is conducive to the improvement of infrared emission.So Cs₃Bi_2-m-nEr_mDy_nBr₉perovskite glass is a potential 3μm wide spectrum laser gain medium.