Optical properties of a dual-use phosphor Sr3La2W2O12:Mn4+ for optical thermometry and plant growth lighting

Abstract

The development of Mn4+-activated luminescent materials with high optical thermometric sensitivity remains challenging. In this study, A series of novel red-emitting phosphors Sr3La2W2O12:xMn4+ (0.002≤x≤0.012)) were successfully prepared by high temperature solid state reaction. A systematic investigation was conducted on the crystal structure, elemental composition, photoluminescence characteristics, temperature-dependent luminescence, fluorescence lifetime, and concentration quenching mechanism of this phosphor series. The emission spectrum of phosphor Sr3La2W2O12:Mn4+ exhibits a broad band centered at 717 nm, attributed to the Mn4+ 2Eg→4A2g spin-forbidden transition, which corresponds to far-red emission. This spectral feature aligns well with the far-red absorption band of phytochrome Pfr, making it highly suitable for plant photomorphogenesis applications. Moreover, phosphor Sr3La2W2O12:0.008Mn4+ demonstrates exceptional optical thermometric performance, achieving a relative sensitivity (Sr) of 2.01% K⁻¹. Given its outstanding luminescent and thermal sensing properties, phosphor Sr3La2W2O12:Mn4+ emerges as a promising bifunctional material for applications in non-contact optical thermometry and energy-efficient plant growth lighting systems.