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Orientation‐Engineered Small‐Molecule Semiconductors as Dopant‐Free Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells
Author(s) -
Zhou Zhiwen,
Wu Qisheng,
Cheng Rui,
Zhang Hong,
Wang Sijia,
Chen Mojun,
Xie Maohai,
Chan Paddy Kwok Leung,
Grätzel Michael,
Feng ShienPing
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202011270
Subject(s) - materials science , dopant , electron mobility , stacking , substrate (aquarium) , organic semiconductor , perovskite (structure) , semiconductor , optoelectronics , molecule , nanotechnology , crystallography , doping , organic chemistry , chemistry , oceanography , geology
Crystallized p‐type small‐molecule semiconductors have great potential as an efficient and stable hole transporting materials (HTMs) for perovskite solar cells (PSCs) due to their relatively high hole mobility, good stability, and tunable highest occupied molecular orbitals. Here, a thienoacene‐based organic semiconductor, 2,9‐diphenyldinaphtho[2,3‐ b :2′,3′‐ f ]thieno[3,2‐ b ]thiophene (DPh‐DNTT), is thermally evaporated and employed as the dopant‐free HTM that can be scaled up for large‐area fabrication. By controlling the deposition temperature, the molecular orientation is modulated into a dominant face‐on orientation with π–π stacking direction perpendicular to the substrate surface, maximizing the out‐of‐plane carrier mobility. With an engineered face‐on orientation, the DPh‐DNTT film shows an improved out‐of‐plane mobility of 3.3 × 10 −2 cm 2 V −1 s −1 , outperforming the HTMs reported so far. Such orientation‐reinforced mobility contributes to a remarkable efficiency of 20.2% for CH 3 NH 3 PbI 3 inverted PSCs with enhanced stability. The results reported here provide insights into engineering the orientation of molecules for the dopant‐free organic HTMs for PSCs.