Tailoring of Visible‐NIR‐II Luminescence in Pt<sup>4+</sup>/Er<sup>3+</sup>‐Codoped Cs<sub>2</sub>ZrCl<sub>6</sub> Double Perovskite Phosphors via Energy Transfer Engineering for Diversified Applications
Chao Jiang, Quan Liu, Li Li, Kaiyang Li, Yubo Feng, Ying‐Kai Fu, Yidong Li, Xu Qian, Bo Wei, Peng Du
Abstract
Abstract To settle the unsatisfied efficiency of near‐infrared (NIR) emission in lanthanide‐doped luminescent materials, a series of Pt 4+ ‐doped and Pt 4+ /Er 3+ ‐codoped Cs 2 ZrCl 6 double perovskite phosphors are designed. Excited by 254 nm, Pt 4+ ‐doped Cs 2 ZrCl 6 compounds can exhibit the characteristic emissions of host and Pt 4+ , resulting in the polychromatic luminescence caused by the efficient energy transfer from host to Pt 4+ . Through combining the theoretical calculation and luminescence profiles, it is clear that the broadband emission at 660 nm is assigned to the self‐trapped exciton of [PtCl 6 ] 2− octahedron. Furthermore, compared with that of Er 3+ ‐doped sample, the intensity of the NIR‐II emission of Er 3+ at 1540 nm in Pt 4+ /Er 3+ ‐codoped Cs 2 ZrCl 6 double perovskite phosphors is greatly improved, namely, a 127‐fold increase, due to efficient energy transfer from host and Pt 4+ to Er 3+ . Furthermore, the quantum efficiencies of the visible and NIR‐II emissions in Cs 2 ZrCl 6 :0.6%Pt 4+ /25%Er 3+ double perovskite phosphor are 75.5% and 34%, respectively, excited by 254 nm. Additionally, via utilizing the designed phosphors, various applications including multilevel anti‐counterfeiting, non‐visual imaging, night vision, etc., are realized. This finding implies that NIR‐II emission of Er 3+ in double perovskite phosphors can be efficiently regulated via using multi‐channel composite energy transfer engineering.