Perovskite CsPbX3 (X=Cl, Br, I) Nanocrystals in fluorophosphate glasses

摘要

For the first time, CsPbX3 (X=Cl, Br, I) nanocrystals (NCs) are synthesized in fluorophosphate glasses. The controlled formation of CsPbX3 quantum dots is realized by adjustment of cooling rate and heat treatment conditions. X-ray diffraction data and optical measurements have confirmed the formation of 4-11 nm sized CsPbX3 nanocrystals. The crystallization of CsPbCl3 is assumed to proceed according to a heterogeneous mechanism, with small CsPbBr NCs acting as nuclei. The introduction of two anions (Cl, Br or Br, I) has results in the appearance of two narrow bands in the luminescence spectra corresponding to quantum dots with different chemical compositions, suggesting that the preparation of NCs with a mixed anion is complicated by phase segregation during the high-temperature synthesis. The photoluminescence of CsPb(Cl, Br)3 quantum dots has a high intensity with a quantum yield of 45-50 % and narrow emission band.