气候变化领域集成服务门户(CCPortal): Designing high performance all-small-molecule solar cells with non-fullerene acceptors: Comprehensive studies on photoexcitation dynamics and charge separation kinetics

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DOI	10.1039/c7ee02967e
	Designing high performance all-small-molecule solar cells with non-fullerene acceptors: Comprehensive studies on photoexcitation dynamics and charge separation kinetics
	Shi J.; Isakova A.; Abudulimu A.; Van Den Berg M.; Kwon O.K.; Meixner A.J.; Park S.Y.; Zhang D.; Gierschner J.; Lüer L.
发表日期	2018
ISSN	17545692
起始页码	211
结束页码	220
卷号	11 期号:1
英文摘要	Solution-processable all-small-molecule organic solar cells (OSCs) have shown dramatic progress in improving stability and photovoltaic efficiency. However, knowledge of photoexcitation dynamics in this novel class of materials is very limited. To fully exploit the design capacities inherent in small molecule chemistry, the elementary processes and branching yields must be known in detail. Here, we present a combined computational-experimental study of photoexcitation dynamics of a prototypical all-small-molecule photovoltaic blend, p-DTS(FBTTh2)2 as a donor and NIDCS-MO as an acceptor. Femtosecond spectroscopy data show that excitonic coupling is small and that the charge transfer states are localized, at first glance contradicting the high internal quantum efficiency (IQE) and open circuit voltage (VOC) of this material. A target analysis of the femtosecond spectra yields exciton dissociation rates of 1/(25 ps) and 1/(100 ps) for the as-deposited and annealed blend, respectively. These rates are far slower than in typical polymer based organic solar cells. Still, internal quantum yields are high because parasitic quenching processes are found to be even slower. In the framework of semiclassical Marcus theory, we demonstrate that our system shows near-optimum energy conversion and charge separation yields, due to negligible activation energy for charge generation but high activation energy for charge recombination, allowing enough time to separate localized charge transfer states. We thus justify both the high internal quantum yields and the high open circuit voltage found in this system. Finally, we predict that highly efficient and stable low-optical bandgap systems can be realized by reducing the electronic coupling between the donor and acceptor. © The Royal Society of Chemistry.
英文关键词	Activation energy; Blending; Charge transfer; Chemical activation; Computation theory; Dissociation; Dynamics; Energy conversion; Molecules; Open circuit voltage; Organic solar cells; Photoexcitation; Polymer solar cells; Quantum efficiency; Quantum theory; Quantum yield; Separation; Solar power generation; Charge recombinations; Charge transfer state; Femtosecond spectroscopy; High activation energy; Internal quantum efficiency; Photo-voltaic efficiency; Small-molecule organic solar cells; Solution processable; Solar cells; activation energy; design; efficiency measurement; electronic equipment; fuel cell; fullerene; performance assessment; photovoltaic system; polymer
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190349
作者单位	Madrid Institute for Advanced Studies, IMDEA Nanoscience, Campus Cantoblanco, Calle Faraday 9, Madrid, 28049, Spain; Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 15, Tubingen, 72076, Germany; Center for Supramolecular Optoelectronic Materials, WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, ENG 445, Seoul, 151-744, South Korea
推荐引用方式 GB/T 7714	Shi J.,Isakova A.,Abudulimu A.,et al. Designing high performance all-small-molecule solar cells with non-fullerene acceptors: Comprehensive studies on photoexcitation dynamics and charge separation kinetics[J],2018,11(1).
APA	Shi J..,Isakova A..,Abudulimu A..,Van Den Berg M..,Kwon O.K..,...&Lüer L..(2018).Designing high performance all-small-molecule solar cells with non-fullerene acceptors: Comprehensive studies on photoexcitation dynamics and charge separation kinetics.Energy & Environmental Science,11(1).
MLA	Shi J.,et al."Designing high performance all-small-molecule solar cells with non-fullerene acceptors: Comprehensive studies on photoexcitation dynamics and charge separation kinetics".Energy & Environmental Science 11.1(2018).