Moisture-Induced reversible structure conversion of Zero-Dimensional organic cuprous bromide hybrids for multiple photoluminescent anti-Counterfeiting, information encryption and rewritable luminescent paper

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 458; p. 141436
• Main Authors: Tian, Ye, Peng, Hui, Wei, Qilin, Chen, Yanxi, Xia, Jingjing, Lin, Wenchao, Peng, Chengyu, He, Xuefei, Zou, Bingsuo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2023
• Subjects: Anti-counterfeiting; Cuprous bromide; Information encryption; Photoluminescence mechanism; Self-trapped exciton; Information encryption; Photoluminescence mechanism; Cuprous bromide; Anti-counterfeiting; Self-trapped exciton
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.141436

[Display omitted] •Two organic cuprous bromide hybrids, namely (TPA)CuBr2 and (TPA)2Cu4Br6, with different coordination geometries were synthesized.•The different lattice structure and charge distribution were the dominant reasons for their different self-trapped exciton emission.•A reversible structural transition triggered by water or heat can be witnessed between (TPA)CuBr2 and (TPA)2Cu4Br6.•We construct a series of anti-counterfeiting, information encryption scenarios and the rewritable PL paper. With social development and the technology advancement, the demand for high-security photoluminescence (PL) anti-counterfeiting and information encryption materials is increasing constantly. Herein, two organic cuprous bromide hybrids, namely (TPA)CuBr2 and (TPA)2Cu4Br6, with variable coordination geometries were synthesized via a facile solution method. (TPA)CuBr2 shines bright cyan emission with a photoluminescence quantum efficiency (PLQE) of 81 % under 254 nm excitation, while (TPA)2Cu4Br6 exhibits orange emission with a PLQE of 95 % upon 365 nm irradiation. Interestingly, a reversible structural conversion could be triggered by water or heat between (TPA)CuBr2 and (TPA)2Cu4Br6, accompanied by a back-and-forth emission color change between cyan and orange under its respective excitation. The emission mechanism of above two compounds was investigated, and the results show that they stem from self-trapped excitons emission. Such PL color switching under the external stimuli of water, heat and different excitation wavelengths enables us to construct a series of anti-counterfeiting and information encryption scenarios. In addition, the rewritable PL paper based on (TPA)CuBr2 with water as ink is realized. These two compounds not only provide a good way to modulate zero-dimensional Cu(I)-based metal halide with highly efficient emission, but also a new example to develop multifunctional applications by organic–inorganic hybrid metal halides.