Super‐Long Persistent Luminescence in the Ultraviolet A Region from a Bi³⁺‐Doped LiYGeO₄ Phosphor

Abstract Here, a novel super‐long, ultraviolet A region (UVA), persistent luminescent (PerL) material, LiYGeO₄:Bi³⁺, is developed. After irradiation at 254 nm for 10 min, the UVA PerL of LiYGeO₄:Bi³⁺ can persist for more than 300 h. In addition, the LiYGeO₄:Bi³⁺ also possesses a strong UVA emission with a power density of 11.83 mW m⁻² at 10 s after the removal of the excitation source. Even after 72 h, the UVA PerL emission spectrum can still be clearly detected, which is the same as the photoluminescence emission spectrum and originated from the Bi³⁺ emitting centers. Furthermore, LiYGeO₄:Bi³⁺ also exhibits a photostimulated PerL property, which can be easily activated with a red light emitting diode (LED) or NIR laser irradiation after the long‐term decay. Combining the results of the PerL excitation, absorption, and thermoluminescence spectra, the excellent UVA PerL of LiYGeO₄:Bi³⁺ can be ascribed to the existence of abundant trap sites created by the loss of Li⁺. This excellent PerL material can make up for deficiency of PerL materials in the UVA region and greatly expand the application of PerL materials in the biomedical, energy, environmental, and catalysis fields.