Blue-green luminescence from mesoporous MCM-48 molecular sieves

Various photoluminescence (PL) methods were used to investigate the blue-green luminescence from mesoporous MCM-48 molecular sieves. The blue-green luminescence intensity is enhanced after rapid thermal annealing. The surface properties of the mesoporous MCM-48 molecular sieves reveal that the generation of twofold coordinated Si centers and non-bridging oxygen hole centers is responsible for this enhancement. Studies of PL following rapid thermal annealing, polarized PL and PL excitation strongly suggest that a triplet-to-singlet transition of twofold-coordinated silicon centers is responsible for the blue-green luminescence in mesoporous MCM-48 molecular sieves. (C) 2004 Elsevier B.V. All rights reserved.