Jie Shao, Xiyang Lia, Meng Liu, Haiqin Sun, Qiwei Zhang, Dengfeng Peng, Fuchi Liu

2024/2/17

Journal of Advanced Ceramics

https://doi.org/10.26599/JAC.2024.922086

Photo-stimuli responsive materials show great potentials in the fields of information encryption and storage due to their distinctive spatial or temporal color changes. However, the conventional single or multi-color static outputs by light stimulus difficultly meet the practical requirements for high security optical storage technologies. Here, a novel dynamic irradiation-responsive phosphor of Na2Ba2Si2O7:Eu is demonstrated, exhibiting high storage stability and convenient readout behaviors. The inherent Eu2+ luminescence can be dynamically tuned, instantly read out, and conveniently erased by controlling irradiation duration of a portable diode laser (365 nm). The modulation mechanism is unraveled by the optically induced oxidation reactions of Eu2+→Eu3+ and defects as killer centers. The excellent luminescence modulation degree (ΔRt=89.5%) and the accompanying larger color contrast enable the creation of invisible optical codes with multi-level encryption in the bright or dark field. These results indicate the potential applications of Na2Ba2Si2O7-based materials in information encryption and invisible optical storage, and are expected to expand more investigations on optically induced PL modulation behaviors based on mixed valences and defects.