Study on PbS/SiO2 quantum-dot-glass prepared by sol-gel method

The sol-gel process has been applied to preparation of small size PbS crystal doped silica glasses. Silica glasses containing 0.87% - 6.6%(wt) PbS were synthesized in a process which includes the two-step hydrolysis of Si (OC2H5)4 and Pb (CH3COO)2 ?? 3H2O, drying and heating of doped gels, and the reaction by exposing the porous glass of PbO/SiO2 to H2S gas. The sol-gel transition point and specific surface area for the doped system were measured. Surfactant microemusion is added to the Sol-gel process to obtain smaller size PbS microcrystal with narrower size distribution. From the results of transmission electron micrographs, PbS crystals were 3 - 6 nm in diameter for methanol method and 2 - 3 nm for microemulsion method. In the optical absorption spectra, the absorption edge exhibited a blue shift compared with that of the bulk PbS, especially for the samples made by microemusion method. Thus the quantum size effect was found for glass containing PbS prepared by the sol-gel process.EI02183-1903