Singh, A.A.SinghChen, H.-C.H.-C.ChenChen, Y.-F.Y.-F.ChenLu, Y.-J.Y.-J.LuWong, K.-T.K.-T.WongKEN-TSUNG WONGYANG-FANG CHEN2021-07-282021-07-282020https://www.scopus.com/inward/record.url?eid=2-s2.0-85085981576&partnerID=40&md5=77a21a7cb342ffc4989d97dd6fc960d4https://scholars.lib.ntu.edu.tw/handle/123456789/573702Herein, core-twisted tetrachloroperylenediimides (ClPDIs) were introduced as new efficient electron-transporting materials (ETMs) to replace the commonly used fullerene acceptor PC61BM in inverted planar perovskite solar cells (PSCs). ClPDI showed a low-lying lowest unoccupied molecular orbital (LUMO) energy level of −3.95 eV, which was compatible with the conduction band of CH3NH3PbI3−xClx (−3.90 eV). In addition, the role of the length of the alkyl side chain at the imide position of ClPDI in modulating the molecular solubility, aggregation capacity for charge-transport properties, surface hydrophobicity, and PSC performance was investigated. The device based on ClPDI-C4 (ClPDI with n-butyl side chains) as ETM achieved a maximum power conversion efficiency (PCE) of 17.3 % under standard AM 1.5G illumination, which iwas very competitive with that of the reference device employing PC61BM/C60 (PCE=17.2 %) as ETM. Moreover, the devices with ClPDIs as ETMs exhibited better device stability than that with PC61BM/C60. This work highlights the great potential of ClPDI derivatives as low-cost (≈2.0 USD g−1) and effective ETMs to obtain efficient solution-processed inverted PSCs. This class of ClPDI derivatives is expected further promote the performance and stability of PSCs after extended investigation. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim[SDGs]SDG7Costs; Fullerenes; Molecular orbitals; Perovskite; Perovskite solar cells; Alkyl side chains; Device stability; Electron transporting materials; Lowest unoccupied molecular orbital; Organic electron transporting materials; Reference devices; Solution-processed; Surface hydrophobicity; Chlorine compoundsjournal article10.1002/cssc.202000728323144992-s2.0-85085981576WOS:000537589100001