Asymmetric Benzotrithiophene-based hole transporting materials provide high-efficiency perovskite solar cells
Journal
ACS Applied Materials and Interfaces
Journal Volume
12
Journal Issue
26
Pages
29143-29152
Date Issued
2020
Author(s)
Abstract
In this study, we synthesized a series of small-molecule benzotrithiophenes (BTTs) and used them as hole transporting materials (HTMs) in perovskite solar cells (PSCs). The asymmetric benzo[2,1-b:-3,4-b':5,6-b']trithiophene unit was used as the central core to which were appended various donor groups, namely, carbazole (BTT-CB), thieno thiophene (BTT-FT), triphenylamine (BTT-TPA), and bithiophene (BTT-TT). The extended aromatic core in the asymmetric BTT provided full planarity, thereby favoring intermolecular π-stacking and charge transport. The physical, optical, and electrical properties of these small-molecule HTMs are reported herein. BTT-TT displayed good crystallinity and superior hole mobility, when compared with those of the other three HTMs, and formed smooth and uniform surfaces when covering the perovskite active layer. Accordingly, among the devices prepared in this study, a PSC incorporating BTT-TT as the HTM achieved the highest power conversion efficiency (18.58%). Moreover, this BTT-TT-containing device exhibited good stability after storage for more than 700 h. Thus, asymmetric BTTs are promising candidate materials for use as small-molecule HTMs in PSCs. Copyright ? 2020 American Chemical Society.
Subjects
Crystallinity; Efficiency; Hole mobility; Molecules; Perovskite; Synthesis (chemical); Aromatic cores; Candidate materials; Good stability; High-efficiency; Hole-transporting materials; Power conversion efficiencies; Small molecules; Triphenyl amines; Perovskite solar cells
SDGs
Type
journal article