Near‐Unity Photoluminescent Copper(I) Halide Hybrids with Multifunctionality in WLEDs, X‐Ray Scintillation and Information Encryption

ABSTRACT Organic–inorganic copper‐based halides have become a current research hotspot due to their excellent optical properties, structural diversity, favorable stability, and low toxicity. Herein, we report a low‐cost, large‐scale synthesized All‐in‐One (AIO) structural copper(I) halide hybrid material, Cu 6 I 8 (bu‐ted) 2 (bu‐ted = 1‐butyl‐1,4‐diazabicyclo[2.2.2]octan‐1‐ium bromide), which generates broadband green‐yellow emission (530 nm) via self‐trapped excitons (STEs), with excellent photoluminescent quantum yield (99.38% ± 0.41%) and thermal stability (decomposition temperature reaches 295°C). Its multifunctionality has been demonstrated in high‐performance white LEDs (R a = 91.5), ultrasensitive X‐ray imaging scintillators (detection limit: 366.5 nGy air /s, resolution reaches 20 lp/mm), and information encryption labels via reversible emission shifts (Δ λ em = 85 nm) triggered by dichloromethane vapor/solution with rapid KI‐enabled resetting. This work further demonstrates the excellent properties of AIO‐type copper(I) halide hybrid materials and their commercialization potential for multifunctional applications.