Bi3+-doped CsPbX3 (X = Cl/Br, Br, Br/I, I) quantum dots in borogermanate glasses for short-wave cut-off filters

For short-wave cut-off filter application, the CsPbX₃ (X = Cl/Br, Br, Br/I, I) perovskite quantum dots (QDs) glasses have been modified by Bi³⁺ doping based on borogermanate glass matrix. The structure, transmittance (T%), optical density (OD), photoluminescence (PL), PL excitation (PLE), and PL decay of the nanocrystals have been investigated for graded concentrations of Bi³⁺. The Bi³⁺ is partially doped into the CsPbX₃ nanocrystals, and the Bi³⁺-doped nanocrystals are cubic structure. The Bi³⁺ doping significantly suppresses the fluorescence intensity and shortens the PL lifetime for exciton emission of QDs, whereas key performance parameters of filters for the T% and OD are not significantly affected. The operation wavelength is tuned from blue to red light range by varying the halogen anion concentration and ratio. The optimized QDs glass exhibits excellent short-wave cut-off filtering properties, while effectively circumventing exciton emission interference. The decrease in PL intensity and average lifetime for the CsPbX₃ QDs is attributed to the deep energy level traps by Bi³⁺ doping. This study provides a Bi³⁺ doping quenching strategy for the development of high-performance optical filter materials.