Abstract

Silica encapsulated CdSe quantum dots (QDs) with a relatively strong photoluminescence were prepared using 3- mercaptopropyl trimethoxysilane by Stober method at room temperature. The effect of pH of the physiological saline on the photoluminescence was investigated while the nanocomposites were dispersed in it. The results show a comparatively high stability of the luminescence. The thermal stability of the photoluminescence of the composite nanoparticles was also studied. After annealing at 60°C for 2 h, the photoluminescence was kept constant. Then, after annealing at 200°C for 2 h, the photoluminescence was promoted by over 10 times with a marked blue-shifted emission. In addition, the stabilization of the core-shell structured composites against the intense illumination was investigated through the transmission electron microscopy (TEM) observation and the luminescence measurement.

Keywords: Luminescence, stability, CdSe, SiO2, annealing, illumination