Multimodal luminescence in Pr3+ single-doped Li2CaSiO4 phosphor for optical information storage and anti-counterfeiting applications

Discovering multimodal luminescent materials capable of being excited by diverse excitation sources and producing different wavelengths of light emission in a single material system remains a long-standing challenge. Herein, a Pr3+ single-doped Li2CaSiO4 phosphor is reported as an efficient multimodal luminescence material, which responds to convenient light sources including X-ray tube, 450 nm blue LED/laser, and white LED. Upon X-ray excitation, intense long-lasting red (>24 h) and ultraviolet-C (UVC, >12 h) persistent luminescence can be detected simultaneously, enabling a self-sustained glowing material suitable for working in both dark and bright environments. Significant enhancement of UVC afterglow is observed under the continuous photostimulation of white LED. Moreover, under the excitation of blue light, UVC upconversion luminescence is realized with the aid of unique energy levels of the Pr3+ emitter. Besides, this material also exhibits exceptional white-to-brown photochromism performance in bright fields only in response to X-ray irradiation, accompanied by excellent bleaching and recovery capability upon thermal or blue light stimulation. The combination of persistent luminescence, photo-stimulated luminescence, upconversion luminescence and photochromism in this integrated multimodal luminescent Li2CaSiO4:Pr3+ phosphor provides new and exciting directional solutions for multifunctional applications such as optical information storage and anti-counterfeiting.