UV-Vis-NIR luminescence properties and energy transfer mechanism of LiSrPO4:Eu2+, Pr3+ suitable for solar spectral convertor

An efficient near-infrared (NIR) phosphor LiSrPO4:Eu2+, Pr3+ is synthesized by solid-state reaction and systematically investigated using x-ray diffraction, diffuse reflection spectrum, photoluminescence spectra at room temperature and 3 K, and the decay curves. The UV-Vis-NIR energy transfer mechanism is proposed based on these results. The results demonstrate Eu2+ can be an efficient sensitizer for harvesting UV photon and greatly enhancing the NIR emission of Pr3+ between 960 and 1060 nm through efficient energy feeding by allowed 4f-5d absorption of Eu2+ with high oscillator strength. Eu2+/Pr3+ may be an efficient donor-acceptor pair as solar spectral converter for Si solar cells.