Five-level anti-counterfeiting based on versatile luminescence of tri-doped double perovskites
Xingru Yang, Yuhang Sheng, Linglong Zhang, Lun Yang, Fangjian Xing, Yunsong Di, Cihui Liu, Fengrui Hu, Xifeng Yang, Guofeng Yang, Yushen Liu, Zhixing Gan
Abstract
Luminescent materials with multi-emission features are difficult to be replicated, which are highly desirable for advanced anti-counterfeiting. Here, we report the pioneering synthesis of Mn 2+ /Yb 3+ /Er 3+ tri-doped Cs 2 Ag 0.8 Na 0.2 InCl 6 double perovskites (MYE-DP), which exhibit photoluminescence (PL) covering from visible to near-infrared (NIR). The PL colors under excitations of 254 and 365 nm are notably different due to the changed relative emission intensities of self-trapped excitons (STEs) and Mn 2+ d–d transition. Moreover, under the excitation of a NIR laser, the MYE-DP exhibits upconversion (UC) emissions of Mn 2+ and Er 3+ . After ceasing the excitation, the long-lived trapped electrons can be thermally released to Mn 2+ and Er 3+ ions, resulting in both visible and NIR afterglow. Based on multi-modal emissions of the MYE-DP, we demonstrate a five-level anti-counterfeiting strategy, which significantly increases the anti-counterfeiting security. In addition, this work provides valuable insights into the energy transfer between STEs, Mn 2+ , Ln 3+ , and traps, laying a solid foundation for future development of new lead-free perovskites.