Hole transport material based on modified N-annulated perylene for efficient and stable perovskite solar cells

Abstract

N-annulated perylene based materials show outstanding and tunable optical and physical properties, making them suitable to be charge transport materials for optoelectronic applications. However, this type of materials has so far not been well studied in solar cells. Here, we develop a new hole transport material (HTM), namely S5, based on perylene building block terms, for organic-inorganic hybrid perovskite solar cells (PSCs). We have systematically studied the influences of the film thickness of S5 on their photovoltaic performance, and a low concentration of S5 with a thinner HTM film is favorable for obtaining higher solar cell efficiency. S5 shows excellent energy alignment with perovskite as well as high-quality thin film formation, and the PSCs based on S5 as HTMs show remarkable power conversion efficiency (PCE) of 14.90% with a much higher short-circuit photocurrent than that for conventional HTM spiro-OMeTAD (PCE = 13.01%). We conclude that the superior photocurrent for S5 is mainly attributed to the enhanced interfacial hole transfer kinetics as well as the high hole conductivity. In addition, we have investigated the stability of N-annulated perylene derivative as HTMs in PSCs devices, showing that the unencapsulated devices based on S5 demonstrate outstanding stability by remaining 85% of initial PCEs in ambient condition with a relative humidity of ~30–45% for 500 h, while for devices with spiro-OMeTAD the cell efficiency degrade to 57% of initial performance at the same conditions.