Raman scattering, far infrared spectrum of BiI3 nanocrystallites

The optical properties of BiI3 nanocrystallites have been investigated by Raman scattering, far infrared spectrum and UV–vis absorption at room temperature. The Raman and far infrared spectrum of the BiI3 nanocrystallites have a shift in comparison with that of the BiI3 single crystals. The shift is mainly attributed to nanosize effect. The first exciton peak of BiI3 nanocrystallites is a slight blue shift in comparison with the band gap of the bulk materials.