空间限域铅离子与钙钛矿纳米晶间的可逆转换与信息存储应用

发光材料在机密信息保护与防伪领域中发挥着重要作用。钙钛矿纳米晶作为一类高效低成本发光材料可通过两步法原位转换获得, 使其在信息加密、解密领域极具应用前景。本研究探索了“不可见”铅有机框架和发光MAPbBr₃钙钛矿纳米晶间的可逆转换, 以及它们在荧光打印信息存储中的应用。通过铅离子与2-甲基咪唑配位构建新型金属有机框架, 实现铅离子限域分布, 在此基础上通过与甲胺溴原位反应生成钙钛矿纳米晶。利用金属有机框架在可见/紫外光下无光响应的特性, 通过墨水打印对信息进行加密存储。加密信息经甲胺溴喷雾处理, 引发原位反应生成钙钛矿纳米晶, 在紫外光下表现出强光致发光特性, 实现信息解密。利用甲胺溴和水作为解密和加密试剂可实现荧光的多次循环显示与消除。

Reversible Conversion between Space-confined Lead Ions and Perovskite Nanocrystals for Confidential Information Storage

Luminescent materials have been widely used in confidential information protection and anticounterfeiting. Luminescent lead halide perovskite nanocrystals, which can be converted from the lead source through a two-step method, are attractive candidates for information encryption and decryption. Herein, the reversible conversion between the invisible lead-organic framework and the luminescent MAPbBr₃ nanocrystals is achieved, together with their further application on information storage by inkjet printing technology. The lead ions are embedded into the metal-organic frameworks through coordination with the 2-methylimidazole linkers. The inherent confined distribution of lead ions facilitates the in-situ growth of perovskite nanocrystals in the second step without the assistance of external bulky ligands. The recorded information was firstly encrypted by the lead organic frameworks, which is invisible under ambient and UV light. After reacting with methylammonium bromide, the perovskite nanocrystals are in-situ formed, and the information becomes readable under UV light. Using methylammonium bromide and water as the decryption and encryption reagents could also switch on/off the luminescence, therefore, realizing the confidential information storage.