Full-color and time-valve controllable long-persistent luminescence from all-inorganic halide perovskites

Abstract

Abstract Long persistent luminescence (LPL) has gained considerable attention for the applications in decoration, emergency signage, information encryption and biomedicine. However, recently developed LPL materials – encompassing inorganics, organics and inorganic-organic hybrids – often display monochromatic afterglow with limited functionality. Furthermore, triplet exciton-based phosphors are prone to thermal quenching, significantly restricting their high emission efficiency. Here, we present a straightforward wet-chemistry approach for fabricating multimode LPL materials by introducing both anion (Br−) and cation (Sn2+) doping into hexagonal CsCdCl3 all-inorganic perovskites. This process involves establishing new trapping centers from [CdCl6 − nBrn]4− and/or [Sn2 − nCdnCl9]5− linker units, disrupting the local symmetry in the host framework. These halide perovskites demonstrate obviously extended afterglow duration time (> 2,000 s), nearly full-color coverage, and high photoluminescence quantum yield (~ 84.47%). Moreover, they exhibit remarkable anti-thermal quenching properties within the temperature range of 297 to 377 K. Notably, the color-changed time valve of CsCdCl3:x%Br can be precisely controlled by manipulating the concentration of Br− ions, distinguishing them from conventional color-varying long-afterglow materials. Additionally, CsCdCl3:x%Br display time- and temperature-dependent luminescence, while CsCdCl3:x%Sn exhibit forward and reverse excitation-dependent Janus-type luminescence. These characteristics endow the LPL materials with dynamic tunability, offering new opportunities in high-security anti-counterfeiting and 5D information coding. Therefore, this work not only introduces a local-symmetry breaking strategy for simultaneously enhancing afterglow lifetime and efficiency, but also provides new insights into the multimode LPL materials for applications in luminescence, photonics, and information storage.