Energy transfer between Cr³⁺ and Ni²⁺ in transparent silicate glass ceramics containing Cr³⁺/Ni²⁺ co-doped ZnAl<inf>2</inf>O<inf>4</inf> nanocrystals

The emission intensity of Ni2+ at 1200 nm in transparent ZnO-Al2O3-SiO2 glass ceramics containing ZnAl2O4 nanocrystals is improved approximately 8 times by Cr3+ codoping with 532 nm excitation. This enhanced emission could be attributed to an efficient energy transfer from Cr3+ to Ni2+, which is confirmed by time-resolved emission spectra. The energy transfer efficiency is estimated to be 57% and the energy transfer mechanism is also discussed. (C) 2008 Optical Society of America.