Dimerized Small-Molecule Acceptors Afford Efficient and Stable Organic Solar Cells
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초록
내용
High power conversion efficiency (PCE) and operational stability are prerequisites for commercialization of organic solar cells (OSCs). Although the recent development of various small-molecule acceptors (SMAs) has led to OSCs with significantly increased PCEs, these PCEs are still lower than those of other types of photovoltaics such as perovskite solar cells, mainly due to a low open-circuit voltage (Voc < 0.9V). In addition, the long-term stability of OSCs has been considered a major bottle neck for commercialization. To simultaneously address these performance limitations, we develop an new[J.-W. Lee1] oligomer acceptor (DYBO) by dimerizing an SMA, i.e., covalently linking two SMA units with an electron-donating benzodithiophene spacer. DYBO-based OSCs exhibit high PCE (18.08%) with a high Voc (0.968 V), and demonstrate excellent operational stability (a lifetime of over 5 years under 1 sun illumination). The origins of the excellent photovoltaic performance and stability of DYBO-based OSCs are elucidated.