Duxiping Wang, Yuhua Wang, Takatoshi Seto
In this study, a lattice substitution strategy was employed, in which Te6+ replaced W6+ and Lu3+ substituted Mg2+, leading to enhanced quantum efficiency in Mn4+-doped phosphors. Under 365 nm excitation, the newly developed phosphor K0.5La0.5SrMgW0.7Te0.3O6:1.5%Mn4+, 3%Lu3+ shows an internal quantum efficiency of 93.9% and an external quantum efficiency of 77.4%. This phosphor exhibits a broad excitation band from 250 to 600 nm, which covers the weaker spectral response region of silicon solar cells in the near-ultraviolet to visible range. Meanwhile, efficient emission is demonstrated in the stronger spectral response region of 600-800 nm. The increase in EQE is attributed to the release of parity-forbidden transitions and the reduction of defects through symmetry breaking and charge compensation. Two types of light-conversion films including this phosphor were set above and below silicon solar cells. Through their combined effect, the relative photoelectric conversion efficiency of the silicon solar cells was significantly improved by 3.08%, demonstrating excellent application prospects.