Low Temperature Synthesis and Optical Properties of II-VI Metal Sulfide Composite Nanoparticles

초록

Since Murray et al. first reported the chemical synthesis of semiconductor nanocrystals of cadmiumsulfides, so called Hot Injection Method, using organometallic cadmium and sulfur precursors in a high boiling nonpolar coordinating solvent, namely, trioctylphosphine oxide (TOPO), several methods have been developed [4-5]. However, expensive reagents and harsh reaction conditions such as high temperature would be needed for them to exhibit desired optical properties. In this study, II-VI metal sulfide composite nano-materials were prepared in aqueous solution at relatively low temperature by embedding metal sulfide nanoparticles into organosilica particles made of 3-aminopropyl-trimethoxysilanes (APTMS). The metal sulfide nanoparticles were also prepared in aqueous solution by a simple metathesis reaction between inorganic cadmium salt and thiourea. Although as prepared metal sulfide nanoparticles did not show any optical emission, the resulting composite particles exhibited luminescent emissions due to quantum confinement effects and their emission wavelengths could be tuned by simply controlling process parameters such as reaction time, temperature, and the amount of silane in the synthesis.