Multi-responsive deep-ultraviolet emission in praseodymium-doped phosphors for microbial sterilization

Perusing multimode luminescent materials capable of being activated by diverse excitation sources and realizing multi-responsive emission in a single system remains a challenge. Herein, we utilize a heterovalent substituting strategy to realize multimode deep-ultraviolet (UV) emission in the defect-rich host Li2CaGeO4 (LCGO). Specifically, the Pr3+ substitution in LCGO is beneficial to activating defect site reconstruction including the generation of cation defects and the decrease of oxygen vacancies. Regulation of different traps in LCGO:Pr3+ presents persistent luminescence and photo-stimulated luminescence in a synergetic fashion. Moreover, the up-conversion luminescence appears with the aid of the 4f discrete energy levels of Pr3+ ions, wherein incident visible light is partially converted into germicidal deep-UV radiation. The multi-responsive character enables LCGO:Pr3+ to response to convenient light sources including X-ray tube, standard UV lamps, blue and near-infrared lasers. Thus, a dual-mode optical conversion strategy for inactivating bacteria is fabricated, and this multi-responsive deep-UV emitter offers new insights into developing UV light sources for sterilization applications. Heterovalent substituting in trap-mediated host lattice also provides a methodological basis for the construction of multi-mode luminescent materials.开发能够被不同激发光源激发, 并在同一体系中实现多响应发 射的多模态发光材料是发光材料领域的一个挑战. 本文采用一种异价 掺杂策略, 在富含缺陷的Li2CaGeO4 (LCGO)基质中实现了Pr3+掺杂的 多模式深紫外发射. LCGO:Pr3+多响应特性使其能够被常见的光源, 包 括X射线管、标准紫外灯、蓝光和近红外激光器激发. Pr3+掺杂产生并 重建LCGO材料中的缺陷位点, 包括阳离子缺陷的产生和氧空位的减 少, 进而调控了陷阱分布, 使得该材料同时表现出余辉发光和光激励发 光. 基于Pr3+离子的4f离散能级, 该材料还表现出上转换发光, 入射的可 见光可转化为用于杀菌的深紫外发射. 基于此, 本文设计了一种双模光 转换策略用于灭活细菌. 这种多响应的深紫外发射体为开发用于杀菌 的紫外光源提供了新的思路. 在以陷阱为媒介的基质晶格中实施异价 掺杂或者取代也为构建多模发光材料提供了可行途径.