Polythiophene Derivatives Carbonized Polymer Dots: Aggregation Induced Solid‐State Fluorescence Emission^†

Comprehensive Summary Currently, solid‐state fluorescent carbonized polymer dots (CPDs) have attracted attention increasingly due to their applications for optoelectronic display. However, designing CPDs possessing solid‐state fluorescence and clarifying the fluorescence mechanism remain challenging. Herein, we initially synthesized a novel type of polythiophene derivatives CPDs, poly‐4,4’‐(thiophene‐3,4‐diyl)dibenzoic acid carbonized polymer dots (PDBA‐CPDs) with solid‐state fluorescence. Subsequently, the structural and optical characterization revealed that the solid‐state fluorescence originated from the aggregation induced emission of the CPDs. In brief, in aggregation state, the remaining polymer structure groups on the surface of the CPDs overlapped and weakened the non‐radiative transition, enhancing solid‐state fluorescence emission. Thirdly, three polythiophene‐derived CPDs were designed to further demonstrate the aggregation induced solid‐state fluorescence mechanism. Finally, owing to their unique properties of solid‐state fluorescence, the white LEDs (light emitting diodes) were fabricated with high color rendering index (CRI) of 82.7 and CIE coordinates of (0.37, 0.39) using commercial 460 nm chip. This work facilitates the development of CPDs’ solid‐state fluorescence mechanisms and advances the application of CPDs in the field of optoelectronics.