Quantum Size Effect on the Excitation Energy andthe Oscillator Strength of PbI2Clusters in Zeolite

Absorption spectra are reported for PbI 2 clusters incorporated into zeolite FAU with various loading densities. There appear many absorption bands corresponding to one to five molecular clusters. With decreasing the cluster size, the spectra show the remarkable blue shift in qualitative agreement with the quantum confinement of the electron and the hole. The smaller clusters indicate the strong absorption in spite of the decrease in the molecular number. This result is ascribed to the quantum size effect on the exciton oscillator strength.