Chlorinated Fused Nonacyclic Non-Fullerene Acceptor Enables Efficient Large-Area Polymer Solar Cells with High Scalability

As the power conversion efficiency (PCE) of polymer solar cells (PSCs) keeps increasing, developing high-performance large-area PSCs toward commercial application becomes a hot topic in this field. Here, we design and synthesize a non-fullerene acceptor TfIF-4Cl with a fused nonacyclic core via end-group chlorination. Compared to the fluorinated counterpart (TfIF-4F), the combination of the Cl atom in TfIF-4Cl not only leads to red-shifted absorption, but also improves the molecular packing ability. When TfIF-4Cl is blended with the polymer donor PM7 to fabricate the PSC, the device maintains high V OC (0.97 V, corresponding to a low energy loss of 0.60 eV) and presents enhanced J SC and high fill factor (78%), thus leading to an improved efficiency of 14% when compared with a PM7:TfIF-4F-based device. The high V OC but moderate photocurrent of PM7:TfIF-4Cl-based small-area device are beneficial to achieve large-area devices with high scalability according to the Joule’s law; thus, we manufacture 1.01 cm 2 devices and achieve a remarkable PCE of 13.3%, which retain 95% in efficiency when the device area is scaled up from 0.04 to 1.01 cm 2, and represent the best scalability when the device area is scaled up to 1 cm 2 in the literature.