Recently, downconversion materials have attracted considerable research due to large promotion of the efficiency of silicon-based solar cells through the absorption of solar radiation via quantum cutting. However, due to lack of ideal downconversion material, it is emergent to seek novel downconversion phosphors with large ultraviolet absorption and high quantum efficiency. Herein, we reported the photoluminescence performance and dynamics of a downconversion phosphor La₂GeO₅: Bi³⁺, Nd³⁺. This phosphor presents a strong ultraviolet absorption and emits a series of intense near infrared emissions by quantum cutting. The emission energy from the Nd³⁺ matches the energy gap of silicon-based solar cells which can improve the solar cell efficiency.

Energy transfer from Bi³⁺ to Nd³⁺ in La₂GeO₅ occurs, proving that energy transfer mechanism of Bi³⁺→Nd³⁺ is an electric dipole-dipole (DMSO‑d₆) interaction. The energy transfer efficiency of Bi³⁺→Nd³⁺ and theoretical quantum efficiency for La₂GeO₅: Bi³⁺, Nd³⁺ are calculated to be as high as 91% and 191%, respectively. La_1.92GeO₅:0.03Bi³⁺, 0.05Nd³⁺ phosphor presents a promising thermal behavior with an activation energy of 0.152 eV. Thus, the development of near-infrared downconversion Bi³⁺, Nd³⁺ co-doped phosphors might open up a new approach to achieve high efficiency silicon solar cells by means of quantum cutting.