No abstract

Luminescent anti-counterfeiting has the advantages of high secrecy, low cost, flexible design, simple operation, and convenient light-regulation of luminescent materials, which makes it easy to achieve high-level multimodal anti-counterfeiting. Here, zero-dimensional (0D) organic-inorganic hybrid luminescent crystals (TPA)CuBr 2 (TPA + = [N(CH 2 CH 2 CH 3 ) 4 ] + ) with multiple responses to ultraviolet (UV) light, water, and thermal stimulus are synthesized through an ultra-facile approach for multimodal luminescent anti-counterfeiting. Water-sensitive (TPA)CuBr 2 could transform into 0D (TPA) 2 Cu 4 Br 6 upon external water stimulus, accompanied by the change of luminescence color from cyan to orange under UV light irradiation. Both (TPA)CuBr 2 and (TPA) 2 Cu 4 Br 6 exhibit high photoluminescence quantum yields, and long photoluminescence decay lifetimes. In addition, (TPA)CuBr 2 and (TPA) 2 Cu 4 Br 6 show reversible "on-off" luminescence phenomena and excellent cycling stability under thermal stimulus. Exhilaratingly, multimodal anti-counterfeiting luminescent labels with high-security level could be fabricated based on the multiple responsive organic-inorganic hybrid cuprous bromides. Moreover, the test paper based on (TPA)CuBr 2 could be fabricated for the detection of trace water in isopropanol. This work demonstrates the capabilities of (TPA)CuBr 2 and (TPA) 2 Cu 4 Br 6 as high-security anti-counterfeiting materials and luminescent sensors, which provides an important reference for exploring 0D metal halides for high-level luminescent anti-counterfeiting.