Size-quantization effects in the optical spectra of Pbl(2) and Hgl(2) nanocrystals

Size-quantization effects (short-wavelength shift of the structure and broadening) in low-temperature absorption spectra of PbI2 and HgI2 nanocrystals embedded in porous sodium borosilicate glass matrix with pores ranging in size from 2 to 50 nm have been observed and studied. The nanocrystal size was evaluated in the strong quantization approximation. It is shown that the size does not depend on the pore diameter of the matrices used, but is determined by the concentration of the solution introduced into the pores. The absorption and luminescence spectra of the systems thus obtained are shown to evolve as the substance emerges from the pores out onto the surface. The dynamics of formation and the phase composition of the PbI2 and HgI2 crystals on the surface are studied. (C) 1997 American Institute of Physics.