Stepwise Solution-Interfacial Nanoarchitectonics for Assembled Film with Full-Color and White-Light Circularly Polarized Luminescence

The fabrication of chiral thin films with tunable circularly polarized luminescence (CPL) colors is important in developing chiroptical materials but remains challenging due to the lack of assembly-initiated chiral film formation methodology. Here, by adopting a combined solution aggregation and interfacial assembly strategy, we report the fabrication of chiral film materials with full-color and white-light CPL. A biquinoline glutamic acid ester (abbreviated as BQGE) shows a typical aggregation-induced emission property with blue CPL after solution aggregation. Subsequent interfacial assembly of these solution aggregates on a solid substrate leads to the formation of a CPL active film consisting of nanobelt structures. Since the BQGE molecule has a coordination site, the CPL emission of an individual BQGE film can be extended from blue to green emission upon coordination with a zinc ion, accompanied by morphology transition from nanobelts to nanofibers. Further extension to red-color CPL is successfully achieved by coassembly with an achiral acceptor dye. Interestingly, the proper combination of coordination ratio and acceptor loading ratio provides bright white-light CPL emission from the BQGE/Zn2+/PDA triad composite film. This work provides a new approach to fabricating chiroptical film materials with controlled microscopic morphology and tunable CPL properties.制备具有可调圆偏振发光（circularly polarized luminescence, CPL）颜色的手性薄膜，在手性光学材料的开发中具有重要意义，但由于缺乏组装驱动的手性薄膜形成方法，该领域仍面临诸多挑战。本文采用溶液聚集与界面组装相结合的策略，成功制备出具备全色及白光CPL特性的手性薄膜材料。联喹啉谷氨酸酯（biquinoline glutamic acid ester, 缩写为BQGE）在溶液聚集后表现出典型的聚集诱导发光特性，其CPL发射为蓝光。随后将这些溶液聚集体在固体基底上进行界面组装，得到具有纳米带结构的CPL活性薄膜。由于BQGE分子具有配位位点，当其与锌离子配位后，单一BQGE薄膜的CPL发射可从蓝光拓展至绿光，同时其微观形貌从纳米带转变为纳米纤维。通过与非手性受体染料共组装，可进一步将CPL发射拓展至红光波段。有趣的是，通过合理调控配位比例与受体负载比例，BQGE/Zn2+/PDA三元复合薄膜可实现明亮的白光CPL发射。本工作为制备具有可控微观形貌与可调CPL特性的手性光学薄膜材料提供了全新的途径。