화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.341, 1245-1250, 2000
Optical transitions of AgI and AgBr clusters in zeolite FAU
AgI and AgBr clusters are both incorporated into the cages of zeolite FAU. The absorption spectra of these clusters, whose loading densities varied from dilute to four AgI and AgBr molecules per supercage, are discussed. In both samples, the lowest absorption band shifts to the lower energy side with increasing loading density. The large blue shift in AgI clusters compared to the bulk can be qualitatively explained by the model of strong quantum confinement of the photoexcited electron-hole pair In the sample of AgBr clusters with four molecules per cage, however, the energy of the lowest absorption band is close to that of the lowest direct transition of AgBr in bulk. This apparently weak quantum confinement in the photo-excited state seems to originate from the singular band structure in the bulk, i.e., AgBr is the indirect gap material.