Influence of adsorbed CdS nanoparticles on 5Do → 7FJ emissions in Eu3+-doped silica gel

In this paper, we report the enhanced fluorescence from Eu3+-doped silica gels which were prepared by the sol-gel method and subsequently adsorbed with colloidal cadmium sulfide (CdS). Optical absorption, Raman, and photoluminescence studies were employed. The fluorescence intensities were compared for different gels with and without CdS particles by variation in the immersion time in CdS sol. The enhancement of fluorescence was observed for 24 h-immersed gel, dried at 50 degrees C. Photoluminescence studies allowed a plausible mechanism that the enhanced fluorescence could be attributed to a surface electron-trap as an energy donor provided by CdS particle. (C) 2000 Elsevier Science B.V. All rights reserved.