Recent Advances in Fluorescent Polymers with Color-Tunable Aggregate Emission

The modulation of fluorescence properties of light-emitting molecules, especially in solid or aggregate states, is crucial for their practical applications. Polymeric systems offer flexible structural design and solution-processing abilities, affording versatile platforms for achieving color-tunable aggregate fluorescence, especially for those with well-defined structures obtained by controlled polymerization. Meanwhile, the emergence of aggregation-induced emission (AIE) and thermally activated delayed fluorescence (TADF) concepts has revolutionized the field of light-emitting materials, including fluorescent polymers. This Review focuses on the recently developed polymer systems that have realized the fine-tuning of aggregate emissions. It delves into various color-tuning mechanisms, exploring molecular interactions such as dye–dye interactions, charge transfer, energy transfer, and the polymeric microenvironment. Special attention is given to through-space charge transfer (TSCT) and unconventional Förster resonance energy transfer (FRET), which have garnered significant interest recently. We aim to offer valuable insights into molecular structural design from the perspective of fluorescence color-tuning and eventually provide an outlook on potential directions for future research in this field.