Rational Design of Alkynyl-Based Linear Donor-it-Acceptor Conjugated Polymers with Accelerated Exciton Dissociation for Photocatalysis

Boosting the slow exciton dissociation of conjugated polymers (CPs) is of significance for their application in photocatalysis. Extensive research has been dedicated to improve the exciton separation efficiency through the rational molecular design, while constructing donor-pi-acceptor (D-pi-A) structures with larger pi-electron delocalization to extend carrier migrating distance can further promote exciton dissociation. In this work, we reported the design and construction of D-pi-A CP systems by using pyrene, dibenzo[b,d]thiophene 5,5-dioxide, and diethynylbenzene as the donor group, acceptor group, and pi-linker units, respectively, for improving the photocatalytic performance. Density functional theory studies and experimental investigations reveal that the D-pi-A structure can suppress charge recombination, minimize exciton binding energy, and extend the light absorption range, thereby improving the photocatalytic activity in comparison to the A-pi-A and D-pi-D structures. It is believed that this work can provide inspiration for the precise regulation of the D-pi-A system by combining experiments and theoretical calculations, thereby enhancing the photocatalytic performance of CPs.