Tuning the formation of β-phase poly(9,9-di-n-octylfluorenyl-2,7-diyl) via nano-confinement and polystyrene blending for improved photocatalysis

Among all the phase morphologies of poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), the β phase exhibits a zigzag coplanar arrangement with the highest conjugation degree. As a result, the β-phasePFO has extraordinary properties, including enhanced charge carrier mobility. In this work, we report the formation of high-β-phase PFO in nanoparticles (NPs) due to the synergistic effect of the slow crystallization of PFO in nanodroplet confinement and polystyrene (PS) blending. The β-phase content of PFO can be flexibly tuned by varying the NP size, molecular weight (M_w), or relative PS content in the NPs. The novel systems demonstrated in this study are likely to provide valuable insights into the β-phase formation mechanism of PFO. As a proof of concept, we further demonstrate that NPs of PFO:PS (1:8) with a higher β-phase content lead to improved photocatalyst efficiency at lower material costs, allowing for novel designs of efficient and visible-light-driven photocatalytic NPs.