Over the recent years, organic-inorganic hybrid perovskite solar cells (PSCs) have been attracting a massive worldwide attention due to their low cost and facile fabrication. HTM is one of the quintessential components required for the efficient and stable PSC devices. The hunt is now on for new organic semiconductors that are prepared by simple, cost-effective, and green chemistry without sacrificing the efficiency [1].
In this study, a series of donor–acceptor–donor (D-A-D) type small molecules based on the fluorene and diphenylethenyl enamine units, which are distinguished by different acceptors, as hole transporting materials (HTMs) for perovskite solar cells is presented. The incorporation of the malononitrile acceptor units is found to be beneficial for not only carrier transportation but also defects passivation via Pb–N interactions.
The highest power conversion efficiency of over 22% is achieved on cells based on V1359, which is higher than that of spiro-OMeTAD under identical conditions. In addition, we fabricated perovskite solar mini-modules (6.5 × 7 cm) exhibiting efficiency of 18.6%. This shows that HTMs prepared via simplified synthetic routes are not only a low-cost alternative to spiro-OMeTAD but also outperform in efficiency and stability state-of-art materials obtained via expensive cross-coupling methods.
