Crystal Structure Design and Luminescence Performance of NIR Phosphors

Abstract

Near-infrared (NIR) phosphors attract much attention as the promising applications in food composition analysis, night vision, biosensor and so on. Except for Cr3+ ions, some non-Cr3+ ions (Eu2+, Ce3+, Bi3+) recently exhibit innovative broadband NIR light in inorganic phosphors. The key issues are to optimize their photoluminescence quantum yield and reveal unclear “structure–luminescence” relationship. Herein, photoluminescence properties of non-Cr3+-doped NIR phosphors are systematically summarized. Importantly, we propose a significant influence of local crystal structure on NIR luminescence properties. These strategies contain: (1) ligand covalency, (2) strong crystal field and distorted lattice, (3) selective sites occupation and (4) mixed valences. The proposed “structure–luminescence” relationship can provide a new insight to exploit NIR phosphors and optimize current phosphors. Besides, the concept of “high-throughput density functional theory (DFT) prediction-crystal structure design-photoluminescence performances optimization” is summarized to swiftly develop targeted NIR phosphors. Subsequently, energy transfer strategies and application prospects are summarized in details. This review discusses the relationship between crystal structure and NIR light based on high-throughput calculation method. This proposed concept can offer a guidance to exploit a series of novel NIR phosphors and clarify underlying mechanism.