Photoluminescence properties and ultra-fast decay profiles of nanoparticles in sol-gel zirconia thin films xZrO2 • 100-xCds:Mn2+ and Eu3+

Thin zirconia films doped with semiconductor nanocrystals xZrO(2) . 100-x CdS: Mn2+ and Eu3+ (x = 20, 50, 80) were prepared by sol-gel method to classify emission centers by measurements of luminescence, time-resolved luminescence, excitation spectra and decay profiles in the temperature range between 10 and 300 K. The broad emission band over the 24 -13 x 10(3) cm(-1) is found to be composed of four spectral components due to band-edge emission (CdS), ligand to metal charge transfer (LMCT) center (ZrO2), surface-bound deep centers, and lattice-bound d-d (Mn2+) or f-f transition (Eu3+) centers. Luminescence of Mn2+ and Eu3+ showed x-composition-dependent spectral profiles and shortening of lifetimes to 5-50 mus at 10K. Ultra-fast decay components of 0.5-1.5 ns were also detected in thin films at room temperature. Luminescence properties of doped-CdS nanocrystals are characterized by dependence on annealing temperatures, very fast decay times and low thermal activation energy of 1300 cm(-1) in comparison with bulk crystals. (C) 2001 Elsevier Science B.V. All rights reserved.