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DOI	10.1039/d0ee01338b
	Exceptionally low charge trapping enables highly efficient organic bulk heterojunction solar cells
	Wu J.; Lee J.; Chin Y.-C.; Yao H.; Cha H.; Luke J.; Hou J.; Kim J.-S.; Durrant J.R.
发表日期	2020
ISSN	1754-5692
起始页码	2422
结束页码	2430
卷号	13 期号:8
英文摘要	In this study, we investigate the underlying origin of the high performance of PM6:Y6 organic solar cells. Employing transient optoelectronic and photoemission spectroscopies, we find that this blend exhibits greatly suppressed charge trapping into electronic intra-bandgap tail states compared to other polymer/non-fullerene acceptor solar cells, attributed to lower energetic disorder. The presence of tail states is a key source of energetic loss in most organic solar cells, as charge carriers relax into these states, reducing the quasi-Fermi level splitting and therefore device VOC. DFT and Raman analyses indicate this suppression of tail state energetics disorder could be associated with a higher degree of conformational rigidity and uniformity for the Y6 acceptor. We attribute the origin of such conformational rigidity and uniformity of Y6 to the presence of the two alkyl side chains on the outer core that restricts end-group rotation by acting as a conformation locker. The resultant enhanced carrier dynamics and suppressed charge carrier trapping are proposed to be a key factor behind the high performance of this blend. Low energetic disorder is suggested to be a key factor enabling reasonably efficient charge generation in this low energy offset system. In the absence of either energetic disorder or a significant electronic energy offset, it is argued that charge separation in this system is primarily entropy driven. Nevertheless, photocurrent generation is still limited by slow hole transfer from Y6 to PM6, suggesting pathways for further efficiency improvement. © 2020 The Royal Society of Chemistry.
语种	英语
scopus关键词	Carrier mobility; Charge trapping; Fermi level; Heterojunctions; Photoelectron spectroscopy; Rigidity; Charge carrier trapping; Charge separations; Conformational rigidity; Efficiency improvement; Electronic energies; Organic bulk-heterojunction solar cells; Photocurrent generations; Quasi-Fermi level splitting; Organic solar cells; electrical conductivity; energetics; energy efficiency; entropy; photochemistry; photovoltaic system; rotation; separation; solar power
来源期刊	Energy and Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/162848
作者单位	Department of Chemistry, Centre for Processable Electronics, Imperial College London, White City Campus, London, W12 0BZ, United Kingdom; Department of Physics and Centre for Processable Electronics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom; State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China; SPECIFIC, College of Engineering, Bay Campus, Swansea University, Swansea, SA1 8EN, United Kingdom
推荐引用方式 GB/T 7714	Wu J.,Lee J.,Chin Y.-C.,et al. Exceptionally low charge trapping enables highly efficient organic bulk heterojunction solar cells[J],2020,13(8).
APA	Wu J..,Lee J..,Chin Y.-C..,Yao H..,Cha H..,...&Durrant J.R..(2020).Exceptionally low charge trapping enables highly efficient organic bulk heterojunction solar cells.Energy and Environmental Science,13(8).
MLA	Wu J.,et al."Exceptionally low charge trapping enables highly efficient organic bulk heterojunction solar cells".Energy and Environmental Science 13.8(2020).