Dey Somnath
Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar.
Department of Chemistry & Earth Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.
Small. 2019 May;15(21):e1900134. doi: 10.1002/smll.201900134. Epub 2019 Apr 16.
The quest for sustainable energy sources has led to accelerated growth in research of organic solar cells (OSCs). A solution-processed bulk-heterojunction (BHJ) OSC generally contains a donor and expensive fullerene acceptors (FAs). The last 20 years have been devoted by the OSC community to developing donor materials, specifically low bandgap polymers, to complement FAs in BHJs. The current improvement from ≈2.5% in 2013 to 17.3% in 2018 in OSC performance is primarily credited to novel nonfullerene acceptors (NFA), especially fused ring electron acceptors (FREAs). FREAs offer unique advantages over FAs, like broad absorption of solar radiation, and they can be extensively chemically manipulated to tune optoelectronic and morphological properties. Herein, the current status in FREA-based OSCs is summarized, such as design strategies for both wide and narrow bandgap FREAs for BHJ, all-small-molecule OSCs, semi-transparent OSC, ternary, and tandem solar cells. The photovoltaics parameters for FREAs are summarized and discussed. The focus is on the various FREA structures and their role in optical and morphological tuning. Besides, the advantages and drawbacks of both FAs and NFAs are discussed. Finally, an outlook in the field of FREA-OSCs for future material design and challenges ahead is provided.
对可持续能源的追求推动了有机太阳能电池（OSC）研究的加速发展。溶液处理的体异质结（BHJ）OSC通常包含一个供体和昂贵的富勒烯受体（FA）。在过去的20年里，OSC领域致力于开发供体材料，特别是低带隙聚合物，以补充BHJ中的FA。OSC性能目前从2013年的约2.5%提高到2018年的17.3%，这主要归功于新型非富勒烯受体（NFA），尤其是稠环电子受体（FREA）。与FA相比，FREA具有独特的优势，如对太阳辐射的广泛吸收，并且可以进行广泛的化学调控以调节光电和形态特性。本文总结了基于FREA的OSC的现状，例如用于BHJ、全小分子OSC、半透明OSC、三元和串联太阳能电池的宽带隙和窄带隙FREA的设计策略。总结并讨论了FREA的光伏参数。重点是各种FREA结构及其在光学和形态调控中的作用。此外，还讨论了FA和NFA的优缺点。最后，对FREA-OSC领域未来材料设计的前景和面临的挑战进行了展望。
