Energy transfer between silicon-oxygen-related defects and Yb3+ in transparent glass ceramics containing Ba<inf>2</inf>TiSi<inf>2</inf>O <inf>8</inf> nanocrystals

We report on the conversion of near-ultraviolet radiation of 250-350 nm into near-infrared emission of 970-1100 nm in Yb3+-doped transparent glass ceramics containing Ba2TiSi2O8 nanocrystals due to the energy transfer from the silicon-oxygen-related defects to Yb3+ ions. Efficient Yb3+ emission (F-2(5/2)-> F-2(7/2)) was detected under the excitation of defects absorption at 314 nm. The occurrence of energy transfer is proven by both steady state and time-resolved emission spectra, respectively, at 15 K. The Yb2O3 concentration dependent energy transfer efficiency has also been evaluated, and the maximum value is 65% for 8 mol % Yb2O3 doped glass ceramic. These materials are promising for the enhancement of photovoltaic conversion efficiency of silicon solar cells via spectra modification.

National Natural Science Foundation of China [50672087, 50802083, 60778039]; National Basic Research Program of China [2006CB806007]; National High Technology Program of China [2006AA03Z304]; Changjiang Scholars and Innovative Research Team in University [IRT0651]