Designing Semiconducting Polymer Dots for High-Efficiency CO₂ Photoreduction Using the Intramolecular Energy Transfer Strategy

As an appealing class of optoelectronic nanomaterials, semiconducting polymer dots (Pdots) have been extensively used as bioprobes in fluorescence imaging and sensing in recent years. However, the photocatalytic conversion of CO2 using Pdots has been seldom investigated so far. Herein, a series of benzothiadiazole-containing triblock copolymers based on the intramolecular energy transfer strategy was designed for visible light-driven CO2 reduction (>420 nm). Compared with the model polymer poly(9,9-dioctyl-fluorene-alt-5-fluoro-2,1,3-benzothiadiazole) (PFFBT), the prepared triblock copolymers exhibit sharply decreased radiative energy loss, an extended light absorption range, and more efficient charge carrier transport during the photocatalytic process. Using a facile coprecipitation method, the resulting polymers were used as precursors to prepare well-dispersed Pdots in water. Compared to PFFBT Pdots (51.16 μmol h–1 g–1), polymer-20% Pdots exhibit a remarkably high CO yield of 242.11 μmol h–1 g–1, which is one of the highest values among the reported nanopolymer photocatalysts under similar illumination conditions. This study provides important insights into engineering Pdots for the highly efficient photocatalytic reduction of CO2.