A structure-property study of fluoranthene-cored hole-transporting materials enables 19.3% efficiency in dopant-free perovskite solar cells

To date, most of the prevailing organic hole-transporting materials (HTMs) used in perovskite solar cells (PVSCs), such as spiro-OMeTAD and PTAA, generally require a sophisticated doping process to ensure their reasonable hole-transporting properties. Unfortunately, the employed dopants/additives an...

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Bibliographic Details
Published in:Chemical science (Cambridge) 2019-07, Vol.1 (28), p.6899-697
Main Authors: Sun, Xianglang, Wu, Fei, Zhong, Cheng, Zhu, Linna, Li, Zhong'an
Format: Article
Language:English
Subjects:
Additives
Dopants
Energy conversion efficiency
Oxidation
Perovskites
Photovoltaic cells
Solar cells
Transporting
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Summary:To date, most of the prevailing organic hole-transporting materials (HTMs) used in perovskite solar cells (PVSCs), such as spiro-OMeTAD and PTAA, generally require a sophisticated doping process to ensure their reasonable hole-transporting properties. Unfortunately, the employed dopants/additives and the associated oxidation reactions have been shown to deteriorate the long-term device stability seriously. The exploitation of efficient and stable dopant-free HTMs is thus strongly desired for PVSCs. However, effective molecular design strategies for dopant-free HTMs are still lacking. Thus far, only a few of them yielded comparable performance to their doped counterparts, while their synthetic costs are still high. In this work, a new class of cost-effective small molecule dopant-free HTMs have been developed using readily available fluoranthene as the structural framework. The structure-property correlation of the fluoranthene-based HTMs was carefully investigated by tuning their structural geometry (linear vs. branched), connection between electron-donating and electron-withdrawing moieties (single bond vs. ethylene), and the substitution position of the methoxy side-groups ( para - vs. meta -). As a result, the optimized molecule, FBA3 , was demonstrated to serve as an efficient dopant-free HTM in a conventional PVSC to deliver an impressive power conversion efficiency of 19.27%, representing one of the best cost-effective dopant-free organic HTMs reported thus far. A systematic structure-property correlation study was conducted to preliminarily elucidate an inherent regularity governing the structure of dopant-free HTMs.
ISSN:2041-6520
2041-6539
DOI:10.1039/c9sc01697j