Preparation And Optical Properties Of Tellurite Glass

In recent years,light-emitting diodes?LEDs?have attracted much attention in the lighting field due to their excellent performance and become a new generation of lighting sources.It is well known that commercial white LED are obtained by combining phosphors with blue or near ultraviolet?n-UV?chips.For a long time after the operation,many problems of phosphors appear,such as yellowing,low luminous efficiency,and short lifetime,etc,which affect luminescence of LED devices.In this paper,based on tellurite glasses,rare earth ions and CsPbBr₃ perovskite quantum dots?PQDs?are smelt into glass matrix by high-temperature melting technology.The structural characteristics,optical properties,and luminescent mechanism of rare earth ions doped luminescent glasses and CsPbBr₃ PQDs glass-ceramics have been studied in depth by a series of characterization methods.The main contents of the dissertation are as follows:1.Tellurite glass matrixes in binary or ternary system based on TeO₂were synthesized by high-temperature melting technique.The FTIR,RAMAN and MAS-NMR show that non-bridging oxygens in the glass network increase with the incorporation of an appropriate amount of Zn O,and some physical properties change significantly.At the same time,the proportion of borate tetrahedral[BO₄]units increase,which further improves the formation ability of the TeO₂-B₂O₃-ZnO system glass.A tendency is observed that the tellurate tetrahedral[TeO₄]unit transform to a triangular pyramid[TeO₃]unit.After introducing higher content of ZnO as an alternative of B₂O₃,the stability of the glass matrix becomes more worse.2.A series of Dy³⁺/Eu³⁺single-doped and co-doped 70TeO₂-20B₂O₃--10ZnO?denoted as TBZ?tellurite glasses were prepared by high-temperature melting technique.Under the excitation of 387 nm,the characteristic emission bands of Dy³⁺/Eu³⁺ions are observed in Dy³⁺/Eu³⁺co-doped TBZ glass.The fluorescence spectra and decay curves confirm the existence of energy transfer from Dy³⁺to Eu³⁺ions in TBZ glass.The relative intensity of green and red emisson can be tuned by changing the concentration of Dy³⁺and Eu³⁺ions.When the concentrations of Dy³⁺and Eu³⁺ions are 2%and 2%,respectively,white emission is achieved and the CIE coordinates is?0.351,0.334?.In addition,Dy³⁺/Eu³⁺co-doped TBZ glass exhibits very high thermal stability compared to commercial Y₃Al₅O₁₂:Ce³⁺phosphors.Therefore,luminescence tuning of glasses can be adjusted by changing the concentration and energy transfer,thereby realizing a high-power white LED.3.CsPbBr₃ PQDs glass-ceramics with 60TeO₂-20BaF₂-18B₂O₃--2Al₂O₃ as the matrix were prepared by high-temperature melting bonding heat treatment technology.The CsPbBr₃ PQDs are uniformly distributed in the glass matrix by analyzing XRD,TEM,XPS and other characterized data.Under 370 nm excitation,the emission wavelength is slightly tuned in the range of 519-522 nm,and it shows strong green emission at 365 nm UV lamp.When reheated at 380?for 3 h,the fluorescence emission peak is located at 520 nm?FWHM=31 nm?,and CsPbBr₃ PQDs glass-ceramics shows good luminescent performance.In addition,compared with pure CsPbBr₃ PQDs prepared by liquid phase method,it shows excellent thermal stability and water stability.The white light obtained through assembly with n-UV chips and Eu³⁺doped CsPbBr₃PQDs glass-ceramics,which is expected to apply in high-power solid state light source.