Novel long-lifetime photoluminescence of nanosized ZnO included in the mesoporous MCM-41

The photoluminescence behavior of ZnO is largely dependent on its defect properties that are resulted from different preparation conditions. In this Letter, several kinds of nanosized ZnO are successfully encapsulated in the mesopores of the MCM-41 with different starting materials and at various calcination atmospheres. A novel long-lifetime photoluminescence of the nanostructured ZnO is observed for the first time and is attributed to the donor-acceptor pair (DAP) luminescence. The time-delayed spectra and decay kinetics of the DAP luminescence are also presented. An energy-state model depicting the luminescence is proposed finally, which would be useful for our understanding the mechanism of the blue or green emission of ZnO. (C) 2004 Elsevier B.V. All rights reserved.