摘要
近年来,基于非富勒烯受体(NFAs)的有机太阳能电池(OSCs)取得了迅猛的发展.单异质结OSCs的光电转换效率(PCE)已突破19%,这进一步推动了有机光伏技术的商业化进程.光电转换效率的快速提升源于活性层材料的创新开发、器件工程的优化以及对器件物理的更深刻理解.然而,稳定性问题已成为制约其商业化的一个主要因素.目前,关于活性层材料和电池器件稳定性的研究仍相对有限.在本综述中,我们对NFA-OSCs不稳定性的机理进行了简要介绍,包括NFAs的光氧化降解、不稳定的共混薄膜形貌以及界面层诱导的NFAs不稳定性.同时,我们总结了近年来国内外关于提高NFA-OSCs稳定性的研究策略.期望本综述能为实现高效、稳定的NFA-OSCs提供有益的指导.
Abstract
Bulk-heterojunctions(BHJ)Organic solar cells(OSCs)have garnered considerable attention in the past two decades due to their advantages,including mechanical flexibility,lightweight,low-cost solution-processability,and semitransparency.The recent years have witnessed rapid progress in the realm of OSCs centered around non-fullerene acceptors(NFAs)thanks to the distinct merits of NFAs's stronger and broader absorption,highly adjustable energy levels,and easily modification of molecular structures.The power conversion efficiency(PCE)of single-junction OSCs has now reached high values of over 19%,which brings them closer to the threshold for commercial viability.This increase in PCE is attributed to advancements in active layer materials,device engineering,and a deeper comprehension of device physics.Nevertheless,achieving high PCE is not the only requirement for commercialization,while the stability of the devices is equally pivotal.The photovoltaic performance degradation of BHJ OSCs devices has been widely observed,however,the research on the stability of NFA-based OSCs has received less attention than efforts directed towards improving PCE through novel material development.The instability of NFA-OSCs has been one of the key obstacles limiting their transition to commercial applications.Various factors,encompassing both external and intrinsic variables,influence their stability.External factors,such as light,heat,water,and stress,exert significant impact on the stability of OSCs.Effective encapsulation can protect the devices from contact with oxygen and water,curtailing degradation.Encapsulated OSCs have demonstrated encouraging operational lifetimes of several years under certain degradation environments,in stark contrast to unencapsulated OSCs which often succumb to rapid degradation,losing their performance within a matter of minutes to days.Intrinsic degradation processes within NFA-OSCs involve material stability,morphology stability of BHJ and interface stability.The degradation of NFA based cells was not fully investigated as has been done on the fullerene based OSCs.There remains a lack of concrete molecular design rules to enhance the stability of NFA based OSCs.Therefore,it is still highly needed to further understand the intrinsic degradation processes of NFA-OSCs and to find proper ways to suppress these degradation processes.Herein,in this context,we present a comprehensive review encompassing the intrinsic fundamentals of instability including photo-oxidation of NFAs,interlayer-induced degradation of NFAs and the blend film morphology.Furthermore,we summarize recent advancements in strategies aimed at enhancing the stability of NFA-OSCs.These include stable NFA molecular design,mitigation of interfacial chemical reactions,and implementation of ternary strategies.It is our aspiration that this concise review will serve as a valuable resource for researchers interested in stability considerations,providing a guiding framework for future endeavors in achieving both efficient and stable NFA-OSCs.
维普
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