Luminescent properties of CsPb(Br_хCl_1–х)₃ nanocrystals in fluorophosphate glass

Vorobev M.V., Shvets E.V., Kuzmenko N.K., Kolobkova E.V. Luminescent properties of CsPb(Br_хCl_1–х)₃ nanocrystals in fluorophosphate glass. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2026, vol. 26, no. 4, pp. 724–731 (in Russian). doi: 10.17586/2226-1494-2026-26-4-724-731

CsPb(Br_хCl_1–х)₃ perovskite nanocrystals were synthesized in fluorophosphate glass by melt quenching followed by subsequent heat treatment. The variation of the chlorine (Cl) and bromine (Br) ion ratio in the glass affected the composition and, consequently, the band gap ΔЕg of the perovskite nanocrystals, enabling tunable photoluminescence from green to blue emission. The spectral and luminescent properties of CsPb(Br_хCl_1–х)₃ nanocrystals formed in fluorophosphate glass were investigated for different Br/Cl ratios. Fluorophosphate glasses containing CsPb(BrхCl1–х)3 nanocrystals were prepared by high-temperature synthesis from batch chemicals followed by additional heat treatment above the glass transition temperature. The heat-treatment temperature was determined from differential scanning calorimetry data obtained using a STA 449F1 Jupiter Nietzsche analyzer. Absorption spectra were measured with a PerkinElmer Lambda 650 double-beam spectrophotometer. Photoluminescence spectra were recorded using a PerkinElmer LS50B spectrofluorometer. The absolute photoluminescence quantum yield was measured with a Hamamatsu absolute quantum yield measurement system equipped with an integrating sphere. CsPb(Br_хCl_1–х)₃ perovskite nanocrystals with different Br/Cl ratios were successfully formed in fluorophosphate glass. The growth of nanocrystals in the glass matrix was controlled by isothermal treatment at temperatures above Tg through adjustment of the treatment temperature and duration. Optical measurements confirmed the formation of CsPb(Br_хCl_1–х)₃ nanocrystals. The photoluminescence peak position shifted within the range of 430–512 nm. A decrease in the photoluminescence quantum yield of CsPb(Br_хCl_1–х)₃ was observed with increasing Cl concentration in the nanocrystals. This effect can be attributed to the enhancement of nonradiative recombination pathways in the glass matrix, including the formation of deep trap states and increased surface recombination. It is concluded that fluorophosphate glasses containing CsPb(Br_хCl_1–х)₃ nanocrystals can be used as blue and green phosphors in the 450–500 nm spectral range.