Achieving over 17% efficiency of ternary all-polymer solar cells with two well-compatible polymer acceptors

The field of all-polymer solar cells (all-PSCs) has experienced rapid development during the past few years, mainly driven by the design of efficient polymer acceptors (P(A)s). However, the polymer/polymer blend systems still lag far behind polymer/small molecule acceptor counterparts in power conversion efficiencies (PCEs). Here, we designed a near-infrared P-A PY2F-T and paired it with polymer donor PM6 to fabricate all-PSCs with 15.0% PCE. Afterwards, PYT as the third component was introduced into the PM6: PY2F-T host system. Because of the complementary absorption bands and finely tuned microstructures of the ternary blend, the PCE is improved up to 17.2%, with the external quantum efficiency over 80% in visible and near-infrared spectral regions. Impressively, the ternary blend exhibited less energy loss, better light- soaking and photo-thermal stabilities than did the corresponding binary systems. This work promotes the development of high-performance ternary all-polymer systems and heralds a brighter future for accelerating the possible applications of all-PSCs.