PbI_2 nanoclusters in zeolite LTL: host-guest chemistry and optical properties

摘要

We report here on the development of host-guest and guest-guest interaction in coursernof preparation procedures semiconductor clusters PbI_2, in the zeolite LTL matrix. Opticalrnproperties of practically unexplored PbI2/zeolite LTL system have been investigated. Both inrnabsorption (reconstructed from diffuse reflection via Kubelka-Munk function) andrnluminescence spectra the features were observed at the energies much exceeding the excitonrnresonance energy Eex in bulk PbI2. This is considered as an indication of size quantizationrnthough the unambiguous attribution of the respective transitions requires further studies,rnincluding theoretical ones. For the samples with relatively high PbI2 content the narrowrnemission peak only slightly blue-shifted from Eex was observed and attributed to longrnclusters formed inside the main channels of zeolite LTL lattice and possibly retaining thernlayer structure of bulk PbI2. The gradual disappearance of this peak during the storage of thernsamples in the air is explained by assuming that originally formed long clusters undergornfragmentation into smaller species.