Binary additives synergistically boost the efficiency of all-polymer solar cells up to 3.45%

Binary additives synergistically boost the power conversion efficiency of all-polymer solar cells up to 3.45%. The nonvolatile additive PDI-2DTT suppresses aggregation of the acceptor PPDIDTT and enhances donor/acceptor mixing, while the additive DIO facilitates aggregation and crystallization of the donor PBDTTT-C-T as well as improves phase separation. Combination of DIO and PDI-2DTT leads to suitable phase separation and improved and balanced charge transport, which is beneficial to efficiency enhancement.