Size control and photoluminescence enhancement of CdS nanoparticles prepared via reverse micelle method

Uniform CdS nanoparticles from 4 to 8 nm have been synthesized via a quaternary reverse micelle method. The size of the nanoparticles can be controlled and modulated by adjusting the W (W=[H2O]/[CTAB]) value. In order to eliminate the surface defects and improve the optical properties of CdS nanoparticles, the reflux treatment was employed. Compared with the freshly prepared CdS nanoparticles which mainly presented the broad defect emission, the nanoparticles treated by reflux exhibited narrow band size dependent exciton emission and its intensity was enhanced greatly, due to the effective surface modification. The possible mechanism of effective surface modification is discussed and the highest quantum yield of CdS nanoparticles at room temperature is estimated to be 11%.