Near-infrared downconversion in Eu2+ and Pr3+ co-doped KSrPO4 phosphor

A novel near-infrared (NIR) downconversion (DC) phosphor KSrPO4:Eu2+, Pr3+ is synthesized by the conventional high temperature solid-state reaction. The Eu2+ acts as an efficient sensitizer for Pr3+ in the KSrPO4 host. With broadband near-ultraviolet light excitation induced by the 4f -> 5d transition of Eu2+, the characteristic NIR emission of Pr3+, peaking at 974 nm and 1019 nm due to P-3(0)->(1)G(4) and (1)G(4)-> H-3(4) transitions, is generated as a result of the energy transfer from Eu2+ to Pr3+. The luminescence spectra in both the visible and the NIR regions and the decay lifetime curves of Eu2+ prove the energy transfer from Eu2+ to Pr3+. This Eu2+ and Pr3+ co-doped KSrPO4 phosphor may be a promising candidate to modify the spectral mismatch behavior of crystalline solar cells and sunlight.