Novel dual spectral conversion via Eu2+, Cu+-coactivated core–shell-structured CaS@CaZnOS phosphors for efficient photosynthesis of plants

Abstract

Core–shell-structured CaS:Eu²⁺,Cu⁺@CaZnOS:Cu⁺ phosphors were designed and fabricated to develop a novel dual-excitation dual-emission (DE²) material for efficient solar spectral conversion (SSC) and promote photosynthetic efficiency of greenhouse plants. Under ultraviolet (UV)/green light, CaS:Eu²⁺,Cu⁺@CaZnOS:Cu⁺ phosphors exhibit broadband blue/red emission derived from the transitions of Cu⁺ ions 3d⁹4s–3d¹⁰ and Eu²⁺ ions 4f–5d properties, respectively, with excitation and emission spectra in good agreement with the ground solar spectrum and plant chlorophyll absorption. The UV-to-blue and green-to-red conversion efficiencies of the optimized core–shell structure phosphor are the highest values reported so far, and the luminescent film laminated glasses (LFLGs) prepared with the phosphor have excellent SSC performance, indicating that the phosphor has a good application prospect. The luminescence behavior of Cu ions and the mechanism of energy transfer in the core–shell-structured CaS@CaZnOS are discussed in detail.