OPTICAL-PROPERTIES OF PB2-BASED AGGREGATED PHASE IN NACL AND CSCL ALKALI-HALIDE HOSTS()

The absorption and steady state emission properties of Pb2+-aggregated phase in NaCl and CsCl matrices are found to be close to those of the PbCl2, and CsPbCl3 bulk crystals, respectively. Much shorter picoseco nd decay times have been found for CsPbCl3-like aggregates in CsCl hos t with respect to the bulk CsPbCl3. It is ascribed to microscopic supe rradiance effect and together with the achieved high energy shift of t he exciton absorption peak proves that the quantum confinement effect takes place in the observed emission in CsPbCl3-like aggregates. The a utolocalisation of the cation exciton in PbCl2-like aggregates is cons idered to explain the absence of similar effects in Pb2+-doped NaCl cr ystals.