YNbO 4 :Bi 3+ , Yb 3+ phosphor was prepared to study the quantum cutting process of converting one ultraviolet photon into two near-infrared photons. An intense nearinfrared emission of Yb 3+ : 2 F 5/2 → 2 F 7/2 around 1 µm was observed under the ultraviolet excitation belonging to the broadband absorption of the [NbO 4 ] 3− group and the Bi 3+ ion. The photoluminescence spectra and decay lifetime measurements indicate efficient energy transfer from Bi 3+ to Yb 3+ ions, which is attributed to be of a cooperative energy transfer mechanism. The YNbO 4 :Bi 3+ , Yb 3+ phosphor with optimized doping concentration may be applicable in improving the efficiency of silicon-based solar cells.