High-concentration Mn4+ doping in boron-modified Ca14Zn6Al10O35 – based phosphors: decoding superior luminescence performances†

The application prospects of Mn⁴⁺-activated oxide phosphors are hindered by their relatively weak absorption of blue light, which stems mainly from severe concentration quenching. Ca₁₄Zn₆Al₁₀O₃₅:Mn⁴⁺, noted for its high quantum efficiency and minimal thermal quenching, experiences concentration quenching arising from the direct energy transfer from Mn⁴⁺ ions to the adjacent crystal defects. In this study, a synergistic strategy involving B₂O₃ flux and B³⁺ doping was introduced to mitigate the crystal defects. This strategy elevates the optimal Mn⁴⁺ doping concentration effectively from 1% to 6%, thereby ensuring efficient light absorption in the UV-to-blue band and facilitating intense deep-red emission within the 650–780 nm range. Notably, the quantum efficiency remains above 90% with Mn⁴⁺ doping levels ranging from 1% to 5%. The emission intensity remains stable between 300 and 460 K, with a marked decline only above 500 K. Additionally, the decay lifetime exhibits a linear variation with temperature. These characteristics suggest that the optimal phosphors hold great promise for applications in areas such as indoor agriculture, luminescent thermometers, and solar cells.