Unveiling the underlying mechanism behind the greatly increased properties of Cu(I)-perovskites and their applications for durable WLED and multi-model encryption/decryption

Methods allowing all-inorganic perovskites to be performed on exceptional photophysical property with ultrastability are potentially important. Especially, the development of Cu(I)-perovskites with high photoluminescence quantum yield (PLQY) and stability remains challenge. Herein, a facile and reliable strategy towards CsCu₂I₃ nanocrystals composites (CsCu₂I₃/P-NCCs) by ion–dipole interaction induced space-confined growth within polymer is reported. The greatly enhanced PLQY and superior stability against external stimuli (i.e., UV-irradiation, heat, oxygen/moisture, polar solvents) are primarily attributed to the strong ion–dipole interaction (ΔG = −10.20 eV) between polyethyleneglycol (PEG) and precursor/perovskites as revealed by DFT simulation and experiments, which is unidentified in previous literature. The exceptional optical performance and stability enable the promising application of CsCu₂I₃/P-NCCs in white light-emitting diode (WLED) and anti-counterfeiting, delivering unprecedented color-rendering index (CRI of 95.4) and long half-life time (984h) under continuous illumination, as well as compositional engineered multi-model encryption/decryption. This work demonstrates that the association of weak force has significant influence on perovskites, providing an original principle for the synthesis and application of strongly-emissive and highly-stable perovskites.