Spatial configuration engineering of perylenediimide-based non-fullerene electron transport materials for efficient inverted perovskite solar cells

Due to their excellent photoelectron chemical properties and suitable energy level alignment with per-ovskite, perylene diimide (PDI) derivatives are competitive non-fullerene electron transport material (ETM) candidates for perovskite solar cells (PSCs). However, the conjugated rigid plane structure of PDI units result in PDI-based ETMs tending to form large aggregates, limiting their application and photo-voltaic performance. In this study, to restrict aggregation and further enhance the photovoltaic perfor-mance of PDI-type ETMs, two PDI-based ETMs, termed PDO-PDI2 (dimer) and PDO-PDI3 (trimer), were constructed by introducing a phenothiazine 5,5-dioxide (PDO) core building block. The research mani-fests that the optoelectronic properties and film formation property of PDO-PDI2 and PDO-PDI3 were deeply affected by the molecular spatial configuration. Applied in PSCs, PDO-PDI3 with three-dimensional spiral molecular structure, exhibits superior electron extraction and transport properties, further achieving the best PCE of 18.72% and maintaining 93% of its initial efficiency after a 720-h aging test under ambient conditions. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.