Carbazole, Fluorene, and Silafluorene Bearing Non‐Fullerene Acceptors: Synthesis, Characterization, and Performance in Organic Photovoltaic Devices

Due to their tunable energy levels, ability for intense light absorption, stability and ease of purification, non-fullerene acceptors (NFAs) have significantly contributed to the progress of organic photovoltaics (OPVs). Herein, a series of newly designed and synthesized NFAs specifically tailored are presented for OPV applications. A new class of NFAs possessing carbazole, fluorene, silafluorene derivatives, and benzothiadiazoles are synthesized. The electrochemical and optical investigations are conducted thoroughly. The utilization of these new materials with commercial donor polymers P3HT and PTB7-Th in OPVs shows their potential applications for future studies. The optimal performance is achieved with an inverted structured OPV device, which demonstrates a power conversion efficiency (PCE) of 3.77%, an open-circuit voltage (V_OC) of 1.06 V, a short-circuit current (J_SC) of 9.66 mA cm^- ², and a fill factor (FF) of 37.08%.