Luminescence time decay from Cu + ions in sol–gel silica coatings

Abstract

UV photo-excited luminescence from Cu-doped sol–gel silica coatings has been investigated. The intense emission in the visible part of the spectrum is assigned to electronic transitions 3d 94s 1→3d 10 in Cu + ions. Photoluminescence time decay corresponding to this emission has been measured in the temperature range of 80–300 K. The curves resulted biexponential functions with two temperature-dependent time constants. The results have been analysed in terms of a three level model including the effect of non-radiative transitions. A comparison between these results and those obtained from Cu + ions embedded in crystalline matrices shows differences in the value of the parameters governing the luminescent process. These differences are interpreted in terms of the local environment of Cu + in the glassy network.