Rationalizing Small-Molecule Donor Design toward High-Performance Organic Solar Cells: Perspective from Molecular Architectures

Tuning donor/acceptor interfacial arrangements and electron-transfer processes in the active layers is crucial to improve the performance of organic solar cells (OSCs). Here, the impact of different molecular architectures (i.e.,A-pi-D-pi-A, D-pi-A-pi-D and pi-A-D-A-pi) of the donors on the interfacial arrangements and electronic processes in small-molecule (SM) OSCs is elucidated by means of multiscale theoretical simulations. An A-pi-D-pi-A structured donor with sizable terminal units, extended It bridges, and bulky side groups on the backbone core is proved to be able to simultaneously obtain both efficient charge generation and migration as well as suppressed charge recombination, thus paving the way for the rational design of electron donors toward high-performance SM OSCs.