Broadband downconversion based near-infrared quantum cutting via cooperative energy transfer in YNbO4:Bi3+, Yb3+ phosphor

YNbO4:Bi3+, Yb3+ phosphor was prepared to study the quantum cutting process of converting one ultraviolet photon into two near-infrared photons. An intense near-infrared emission of Yb3+:2F5/2 → 2F7/2 around 1 μm was observed under the ultraviolet excitation belonging to the broadband absorption of the [NbO4]3- group and the Bi3+ ion. The photoluminescence spectra and decay lifetime measurements indicate efficient energy transfer from Bi3+ to Yb3+ ions, which is attributed to be of a cooperative energy transfer mechanism. The YNbO4:Bi3+, Yb3+ phosphor with optimized doping concentration may be applicable in improving the efficiency of silicon-based solar cells.