Long Persistent Luminescence from All‐Inorganic Perovskite Nanocrystals

Abstract The advantages of ultrahigh photoluminescence quantum yield and narrow spectral bandwidth of all‐inorganic lead halide perovskite nanocrystals (NCs) enable them as the most potential candidates for optoelectronic applications. However, it is difficult to obtain long persistent luminescence from inorganic perovskite nanocrystals as the creation of effective trapping centers comes along with the generation of nonradioactive recombination centers. Here, replacing Pb 2+ by appropriate lanthanide ions (Ln 3+ ) in CsPbBr 3 nanocrystals that are embedded inside an amorphous transparent medium via a high‐temperature (≈500 °C) fabrication process is proposed to achieve stable and effective trapping centers. Furthermore, the surface coating of the enclosed nanocrystals prevents the formation of surface defects, leading to long persistent luminescence from CsPbBr 3 : Ln 3+ NCs. The CsPbBr 3 : Ln 3+ NCs with unprecedented high color purity (≈89.9%) and long lasting time of more than 1800 s could be a promising candidate for the application in anti‐counterfeiting.