Multicolor Rare-Earth Film with Ultra-Long Afterglow for Diverse Energy-Saving Applications

Abstract

Rare-earth afterglow materials, with their unique light-storage properties, show great promise for diverse applications. However, their broader applicability is constrained by challenges such as poor solvent compatibility, limited luminescent efficiency, and monochromatic emissions. In this study, these limitations are addressed by blending ZnS with various rare-earth phosphors including (Sr_0.75Ca_0.25)S:Eu²⁺; SrAl₂O₄:Eu²⁺, Dy³⁺ and Sr₂MgSi₂O₇:Eu²⁺, Dy³⁺ to modulate deep trap mechanisms and significantly enhance both the afterglow and light capture capabilities. Using electrospinning, a large-area (0.4 m × 3 m) afterglow film is successfully fabricated with tunable colors and an extended afterglow duration exceeding 30 h. This film demonstrates thermoluminescence, enabling potential integration into fire-rescue protective clothing for enhanced emergency visibility. In greenhouse settings, it effectively supports chlorophyll synthesis and optimizes conditions for plant growth over a 24-h cycle. For tunnel and garage applications, the film captures and stores light from vehicle headlights at distances of up to 70 meters. The scalability and cost-effectiveness of this afterglow film underscore its considerable potential for real-world applications across multiple fields, marking a significant advancement in sustainable illumination technology.