Molecular Engineering of Azahomofullerene-based Electron Transporting Materials for Efficient and Stable Perovskite Solar Cells
Rohit D. Chavan, Bartłomiej Bończak, Joanna Kruszyńska, Apurba Mahapatra, Muhammad Ans, Jan Nawrocki, Kostiantyn Nikiforow, Pankaj Yadav, Jan Paczesny, Faranak Sadegh, Muhittin Ünal, Seçkin Akın, Daniel Prochowicz
Abstract
High Resolution Image Download MS PowerPoint Slide The rational molecular design of fullerene-based molecules with exceptional physical and electrical properties is in high demand to ensure efficient charge transport at the perovskite/electron transport layer interface. In this work, novel azahomofullerene (AHF) is designed, synthesized, and introduced as the interlayer between the SnO 2 /perovskite interface in planar n–i–p heterojunction perovskite solar cells (PSCs). The AHF molecule (denoted as AHF-4) is proven to enhance charge transfer capability compared to the commonly used fullerene derivative [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) due to its superior coordination interaction and electronic coupling with the SnO 2 surface. In addition, the AHF-4 interlayer concurrently improves the quality of the perovskite film and reduces charge recombination in PSCs. The resultant AHF-4-based device exhibits a maximum efficiency of 21.43% with lower hysteresis compared to the PCBM device (18.56%). Benefiting from the enhanced stability of the AHF-4 film toward light soaking and elevated temperature, the AHF-4-based devices show improved stability under continuous 1 sun illumination at the maximum power point and 45 °C. Our work opens a new direction to the design of AHF derivatives with favorable physical and electrical properties as an interlayer material to improve both the performance and stability of PSCs.