Efficient near-infrared down conversion in Nd3+-Yb3+ co-doped transparent nanostructured glass ceramics for photovoltaic application

Abstract

Down conversion involving emission of two near-infrared photons for one ultraviolet photon absorbed was achieved in Nd3+ and Yb3+ co-doped transparent YAG glass ceramics. Upon excitation of Nd3+ ions with an ultraviolet photon at 355nm, Yb3+ ions emitted two near-infrared photons at 980nm through an efficient two-step energy transfer process from Nd3+ to Yb3+. The mechanisms of the two-step energy transfer were verified by spectra and lifetime measurements, and the optimal quantum efficiency achieved was as high as 185.0%, which was close to the theoretical value of 200%. Therefore, the Yb3+ emission centered at 980nm was efficiently enhanced and responded to the strongest absorption of crystalline silicon solar cells. The development of near-infrared down conversion transparent glass ceramics would allow an increase of the energy efficiency of the silicon solar cells.