Energy transfer between Cr^3+ and Ni^2+ in transparent silicate glass ceramics containing Cr^3+/Ni^2+ co-doped ZnAl_2O_4 nanocrystals

The emission intensity of Ni(2+) at 1200 nm in transparent ZnO-Al(2)O(3)-SiO2 glass ceramics containing ZnAl(2)O(4) nanocrystals is improved approximately 8 times by Cr(3+) codoping with 532 nm excitation. This enhanced emission could be attributed to an efficient energy transfer from Cr(3+) to Ni(2+), 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.