Suppression of Defect-Induced Quenching via Chemical Potential Tuning: A Theoretical Solution for Enhancing Lanthanide Luminescence

Nonradiative decay occurring at lattice defect sites may constitute an essential pathway for luminescence quenching in lanthanide-doped upconversion nanomaterials. Considerable efforts have been dedicated to alleviating such quenching effects through controlled single-crystal growth and stringent chemical processing. However, it is not feasible to remove all lattice defects in the crystals. The fabrication of highly luminescent upconversion materials is thus impeded by an incomplete understanding of defect-induced quenching behavior. Here, we propose a theoretical solution for enhancing the luminescence efficiency through the deactivation of deleterious defect centers. To address the exact nature of defect-induced energy dissipation, we systematically study the electronic structure and the stability of five different types of intrinsic defects in cubic NaYF4 crystal through ab initio calculations. Based on the calculated single-particle energy levels and absorption coefficients, we identify optically resp...