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 FITMs 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 their photovoltaic performances sequence as follows: TATF8HBP (11.11%) > TATSFHBP (9.48%) > TATCz3 (0.87%). In addition, the short-circuit current density (J(sc)), open circuit voltage (V-oc) 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.