Realizing Tunable Long Persistent Luminescent in Novel Cu<sup>2+</sup>‐Doped NaGaO<sub>2</sub> for Multi‐Level Information Storage and Encryption
Liang Liang, Heyi Yang, Yuqi Chen, Yang Ding, Fangyi Zhao, Qinan Mao, Meijiao Liu, Jiasong Zhong
Abstract
Abstract Anti‐counterfeiting and encryption are key technologies for information transmission in modern society. However, most optical materials offer only a single fixed response mode, limiting their security level in advanced anti‐counterfeiting applications. Exploring efficient and tunable long persistent luminescent (LPL) phosphors is urgently demanded and highly meaningful. In this work, a dual‐site occupancy strategy is innovatively reported via Li + doped NaGaO 2 : Cu 2+ (NGO: Cu 2+ /Li + ) phosphors for enhancing LPL properties. To be specific, Cu 2+ initially occupies both Na and Ga sites in NaGaO 2 , producing orange–yellow LPL at 585 nm and near‐infrared (NIR) emission at 712 nm, respectively. Furthermore, the introduction of Li + will occupy the Na + sites, attenuating the NIR emission and increasing the defect density of the oxygen‐deficient states, which results in enhanced LPL intensity and prolonged afterglow time. Significantly, the obtained NGO:Cu 2+ /Li + exhibits multi‐emission modes with dynamic change of LPL time (10–20 min). More importantly, the NGO: Cu 2+ /Li + has great potential applications in multi‐level information storage and encryption.