Excitation-dependent colour modulation in Mn2+-doped hybrid perovskites: a universal strategy for luminescent anti-counterfeiting

Organic-inorganic hybrid perovskites are promising for optical encryption and anti-counterfeiting due to their tunable optoelectronic properties. However, conventional monochromatic photoluminescence systems are vulnerable to spectral decryption. This study proposes a universal strategy for synergistic anti-counterfeiting by fabricating (MTP) 2 MnBr 4 composites via solid-state melt processing. The controlled Mn 2+ doping (1–3 mol%) creates a dual-emission system with excitation-dependent colour modulation from green (520 nm) to red (620 nm) through selective activation pathways. The composites are processable into transparent bulk materials and printable inks, enabling multiscale anti-counterfeiting in currency, pharmaceuticals, and luxury packaging. This approach combines accessible materials with scalable protocols, offering a practical route for industrial security applications.