气候变化领域集成服务门户(CCPortal): Assessing the energy offset at the electron donor/acceptor interface in organic solar cells through radiative efficiency measurements

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DOI	10.1039/c9ee02939g
	Assessing the energy offset at the electron donor/acceptor interface in organic solar cells through radiative efficiency measurements
	Xie Y.; Wang W.; Huang W.; Lin F.; Li T.; Liu S.; Zhan X.; Liang Y.; Gao C.; Wu H.; Cao Y.
发表日期	2019
ISSN	1754-5692
起始页码	3556
结束页码	3566
卷号	12 期号:12
英文摘要	Energy offsets at the electron donor/acceptor interface play an important role in the operation of organic solar cells (OSCs), because their magnitude strongly affects the efficiency of photo-induced charge separation and hence the short-circuit current of a device under illumination. However, quantitative assessment of energy offsets in operating devices remains an open challenge that is still out of the reach of present techniques. Here we show that the ratio of the radiative efficiency (EQEEL) for a blend device to that for the lower bandgap component device (usually a non-fullerene acceptor), namely the EQEEL ratio, can be a strong indicator of the energy offsets in the blend device. In photovoltaic devices based on donors and acceptors with similar backbone structure but varied energy levels, lowering the highest occupied molecular orbital (HOMO) offset increases the open-circuit voltage (VOC) from 0.95 V to 1.05 V, which is consistent with the EQEEL variation trends in the devices. The blend EQEEL approaches that of the emissive low bandgap acceptor when the HOMO of the donor is sufficiently deepened, which at the same time corresponds to a reduction in VOC loss and inefficient photoinduced charge separation. The results suggest that the intrinsic energy loss associated with charge separation can be minimized in practice by minimizing the energy offsets but at the expense of lowering the charge separation efficiency. Statistics from several state-of-the-art material systems reveal that efficient charge generation occurs when the EQEEL ratio is less than 0.1, corresponding to an additional non-radiative voltage loss due to the energy offset of 60 mV. Based on this finding and a modified Shockley-Queisser theory, we estimate an upper thermodynamic efficiency limit for single-junction organic solar cells of about 31%, which is slightly below the Shockley-Queisser limit. © 2019 The Royal Society of Chemistry.
语种	英语
scopus关键词	Energy dissipation; Energy gap; Molecular orbitals; Open circuit voltage; Separation; Backbone structures; Highest occupied molecular orbital; Photoinduced charge separation; Photovoltaic devices; Quantitative assessments; Radiative efficiency; Shockley-queisser limits; Thermodynamic efficiency; Organic solar cells; assessment method; energy efficiency; equipment; fuel cell; irradiation; measurement method; organic compound; photodegradation; 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/162859
作者单位	Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China; State Key Laboratory of Fluorine and Nitrogen Chemicals, Xi'An Modern Chemistry Research Institute, Xi'an Shaanxi, 710065, China; Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronics, Southern University of Science and Technology, Shenzhen, 518055, China; Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, 100871, China
推荐引用方式 GB/T 7714	Xie Y.,Wang W.,Huang W.,et al. Assessing the energy offset at the electron donor/acceptor interface in organic solar cells through radiative efficiency measurements[J],2019,12(12).
APA	Xie Y..,Wang W..,Huang W..,Lin F..,Li T..,...&Cao Y..(2019).Assessing the energy offset at the electron donor/acceptor interface in organic solar cells through radiative efficiency measurements.Energy and Environmental Science,12(12).
MLA	Xie Y.,et al."Assessing the energy offset at the electron donor/acceptor interface in organic solar cells through radiative efficiency measurements".Energy and Environmental Science 12.12(2019).