Controlling ESIPT-based AIE effects for designing optical materials with single-component white-light emission

Abstract

Aggregation-induced emission (AIE) molecules have gained significant importance in various fields such as biological imaging and organic light-emitting diodes. Here, we focused on exploring the process of the induction and control of AIE effects by modifying intramolecular hydrogen bonds. Firstly, inspired by the AIE characteristics of our reported amino-type excited-state intramolecular proton transfer (ESIPT)-based molecules, qualitative and quantitative relationships between the acidity of the amino group and the ESIPT process were investigated. They were successfully revealed through artificial intelligence modeling and quantum chemical calculations. Based on this, eight compounds, (2-(2′-aminophenyl) benzothiazole (1) and its derivatives), were synthesized. Then, their mechanism of structural and optical phenomena (AIE or aggregation-caused quenching (ACQ)) was further verified by quantum chemical calculations and experiments. It has been proved that multistage photochemical reactions could lead to the AIE phenomenon. Finally, the eight compounds were applied to biological imaging and white light material applications, benefiting from tunable dual-emission spectroscopic properties of amino compounds with ESIPT properties. This study provided extensive guidance on developing molecules with AIE properties and opened up new avenues for AIE-based principles, as well as single-component white-light emission optical materials.