Constructing High-Performance All-Small-Molecule Ternary Solar Cells with the Same Third Component but Different Mechanisms for Fullerene and Non-fullerene Systems

摘要

Two types of all-small-molecule ternary solar cells consisting of two small-molecule donors and one acceptor (fullereneon-fullerene) are developed. Interestingly, both these devices have a common component: a carefully designed medium bandgap small molecule, which possesses appropriate energy levels and displays good compatibility with the host donor. In the fullerene system, the charge-relaying role of the additive donor is confirmed by the improved charge transportation and suppressed charge recombination. While in the non-fullerene system, the mixed face-on and edge-on orientation of the ternary film induced by the additive donor dominates the promotion of charge transportation. Accordingly, both ternary devices deliver higher short-circuit current density, fill factor, and power conversion efficiencies of over 10% compared to binary ones. This work offers a promising guideline on the construction of high-performance all-small-molecule ternary solar cells by incorporating a miscible small-molecule donor.