Planar perovskite solar cells using triazatruxene-based hyperbranched conjugated polymers and small molecule as hole-transporting materials

摘要： Conjugated polymers have been widely used as hole-transporting materials (HTMs) in planar perovskite solar cells (p-PSCs) and play a vital role in hole transport. In this work, based on triazatruxene (TAT), two hyperbranched conjugated polymers (named as TATF8HBP and TATSFHBP) and a star-shaped carbazole-functionalized small molecule (named as TATCz3) are employed as HTMs in p-PSCs with a well solubility. The differences of these materials between carrier mobility, hole extraction and transmission are investigated due to their discrepancy in molecular structure, leading to their photovoltaic performances sequence as follows: TATF8HBP (11.11%) > TATSFHBP (9.48%) > TATCz3 (0.87%). In addition, the short-circuit current density (Jsc), open circuit voltage (Voc) and fill factor (FF) of p-PSCs show the same trend as PCE does. The results reveal that TATF8HBP exhibits the best performance as a hole-transporting layer (HTL) since the polymer chain and its fluorene unit contribute to the hole transport.