Interfacial layers (interlayers) are one of the emerging approaches in organic solar cells with bulk heterojunction (BHJ) layers because the solar cell efficiency can be additionally improved by their presence. However, less attention is paid to the use of interlayers for polymer:nonfullerene solar cells, which have strong advantages over polymer:fullerene solar cells. In addition, most polymers used for the interlayers possess a low glass transition temperature (T_g). Here, it is demonstrated that two types of quarterthiophene‐containing polyimides (PIs) with high T_g (>198 °C), which are synthesized using pyromellitic dianhydride (PMDA) and cyclobutane‐1,2,3,4‐tetracarboxylic dianhydride (CTCDA), can act as an interfacial layer in the polymer:nonfullerene solar cells with the BHJ layers of poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione))] (PBDB‐T) and 3,9‐bis(2‐methylene(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene) (ITIC), or (3‐(1,1‐dicyanomethylene)‐1‐methyl‐indanone)‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]‐dithiophene) (IT‐M). Interestingly, the efficiency and stability of devices are improved by the PMDA‐based PI interlayers with a stretched chain structure but degraded by the CTCDA‐based PI interlayers with a bended chain structure.

中文翻译：

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高效聚合物：具有含四噻吩的聚酰亚胺中间层的非富勒烯太阳能电池

界面层（中间层）是具有本体异质结（BHJ）层的有机太阳能电池的新兴方法之一，因为它们的存在可以进一步提高太阳能电池的效率。然而，对于聚合物：非富勒烯太阳能电池使用中间层的关注较少，它比聚合物：富勒烯太阳能电池具有强大的优势。此外，大多数用于中间层的聚合物都具有较低的玻璃化转变温度（T _g）。在这里，证明了两种类型的具有高T _g (>198 °C) 的含四噻吩的聚酰亚胺 (PI)，它们是使用均苯四甲酸二酐 (PMDA) 和环丁烷-1,2,3,4-四甲酸二酐（ CTCDA），可以作为聚合物中的界面层：具有聚[（2,6-（4,8-双（5-（2-乙基己基）噻吩-2-基）-苯并BHJ层）的非富勒烯太阳能电池[1,2- b :4,5- b ']二噻吩))- alt -(5,5-(1',3'-二-2-噻吩基-5',7'-双(2-乙基己基)苯并[1',2'-c:4',5'-c']二噻吩-4,8-​​二酮))] (PBDB-T) 和 3,9-双(2-亚甲基(3-(1, 1-二氰基亚甲基)-茚满酮))-5,5,11,11-四(4-己基苯基)-二噻吩并[2,3-d:2′,3′-d′]-s-茚满基[ 1,2- b:5,6-b']二噻吩）（ITIC），或（3-（1,1-二氰亚甲基）-1-甲基茚满酮）-5,5,11,11-四（4-己基苯基）-二噻吩[2,3-d:2',3'-d']- s-茚并烯基[1,2-b:5,6-b']-二噻吩）（IT-M）。有趣的是，基于 PMDA 的拉伸链结构 PI 中间层提高了器件的效率和稳定性，但基于 CTCDA 的弯曲链结构 PI 中间层却降低了器件的效率和稳定性。