Interplay of defect levels and rare earth emission centers in multimode luminescent phosphors

作者：Zhou, Xinquan; Ning, Lixin^*; Qiao, Jianwei; Zhao, Yifei; Xiong, Puxian; Xia, Zhiguo^*

来源：Nature Communications, 2022, 13(1): 7589.

DOI：10.1038/s41467-022-35366-3

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Multimode luminescence generally involves tunable photon emissions in response to various excitation or stimuli channels, which demonstrates high coding capacity and confidentiality abilities for anti-counterfeiting and encryption technologies. Integrating multimode luminescence into a single stable material is a promising strategy but remains a challenge. Here, we realize distinct long persistent luminescence, short-lived down/upconversion emissions in NaGdTi2O6:Pr3+, Er3+ phosphor by emloying interplay of defect levels and rare earth emission centers. The materials show intense colorful luminescence statically and dynamically, which responds to a wide spectrum ranging from X-ray to sunlight, thermal disturbance, and mechanical force, further allowing the emission colors manipulable in space and time dimensions. Experimental and theoretical approaches reveal that the Pr3+ <-> Pr4+ valence change, oxygen vacancies and anti-site Ti-Gd defects in this disordered structure contributes to the multimode luminescence. We present a facile and nondestructive demo whose emission color and fade intensity can be controlled via external manipulation, indicating promise in high-capacity information encryption applications. Information encryption technology calls for versatile multi-mode luminescent materials. Here, the authors develop phosphors with five integrated luminescence modes by exploiting the interplay of defect levels and rare-earth emission centers.