TUNED PHOTOLUMINESCENCE EMISSION OF CDS DOTS EMBEDDED IN MESOPOROUS SILICA

V. DELLA SAVIA; MC MARCHI; GALO SOLER-ILLIA; SARA ALDABE BILMES

Congreso; E-MRS 2005 Spring Meeting; 2005

e-mrs

resumen E/II.04 del archivo adjunto Mesoporous silica films synthesised with different surfactants are used as templates for nucleation and growth of CdS nanoparticles by impregnation in aqueous Cd2+ and S2- solutions. The presence of crystalline CdS nanoparticles within the silica matrix was confirmed by DRX and TEM/SAD/EDS. The photoluminescence emission of CdS in these composites exhibits a narrow excitonic band at ca. 2.6 eV and a broad band in the 2.2-1.9 eV range due to radiative decay of excited surface states. The emission of CdS dots in these silica films is stable for several months. Effects in the position and relative intensity of the excitonic and surface state bands are observed when the mesoporous film is synthesised with CTAB, F127 or Brij 58. CdS nanoparticles included within mesoporous films obtained with CTAB show higher excitonic emission as the CTAB/Si ratio in the precursor silica sol decreases. The main conclusion of this work is that the blue emission of CdS dots can be enhanced by quenching the emission of surface states with appropriate control of the chemistry of the inorganic walls interacting with CdS nanoparticles.