Fabrication of highly luminescent glass incorporating CdTe nanocrystals by using silane coupling agents

CdTe nanocrystals (3-6 nm) prepared by an aqueous method have been embedded in glass matrices through the sol-gel method by using two coupling agents, mercaptopropyl silane (MPS) and aminopropyl silane (APS). The nanocrystals are stabilized by thioglycolic acid (TGA). In the case of MPS, the nanocrystals are dispersed homogeneously because of a thiol group both in TGA and the CdTe surface. However, it takes a month to get a condensed polymer-like sample at room temperature. In contrast, an amino group in APS accelerates the sol-gel reaction drastically. Further, the amino group reacts quickly with a carboxyl group in TGA, This reaction prevents the CdTe from agglomeration. Consequently, stable luminescent glass with good transparency has been prepared in three days. The quantum efficiency of photoluminescence of the glass is similar to5%. The neutral-pH region during synthesis degrades the photo luminescence.