Ultra Robust and Highly Efficient Flexible Organic Solar Cells with Over 18 % Efficiency Realized by Incorporating a Linker Dimerized Acceptor

Abstract

AbstractThe wearable application of flexible organic solar cells (f‐OSCs) necessitates high power conversion efficiency (PCE) and mechanical robustness. However, photoactive films based on efficient non‐fullerene small molecule acceptors (NF‐SMAs) are typically brittle, leading to poor mechanical stability in devices. In this study, we achieved a remarkable PCE of 18.06 % in f‐OSCs while maintaining ultrahigh mechanical robustness (with a crack‐onset strain (COS) of higher than 11 %) by incorporating a linker dimerized acceptor (DOY‐TVT). Compared to binary blends, ternary systems exhibit reduced non‐radiative recombination, suppressed crystallization and diffusion of NF‐SMAs, and improved load distribution across the chain networks, enabling the dissipation of the load energy. Thus, the ternary f‐OSCs developed in this study achieved, high PCE and stability, surpassing binary OSCs. Moreover, the developed f‐OSCs retained 97 % of the initial PCE even after 3000 bending cycles, indicating excellent mechanical stability (9.1 % higher than binary systems). Furthermore, the rigid device with inverted structure based on the optimal active layer exhibited a substantial increase in efficiency retention, with 89.6 % after 865 h at 85 °C and 93 % after more than 1300 h of shelf storage at 25 °C. These findings highlight the potential of the linker oligomer acceptor for realizing high‐performing f‐OSCs with ultrahigh mechanical robustness.