In this work, we systemically investigated the processing solvent-dependent aggregation behavior of a squaraine dye, 2,4-bis[4-(N,N-dibutylamino)-2,6- dihydroxyphenyl] squaraine (DBSQ), in a DBSQ: [6,6]-phenyl-C71-butyric acid methyl ester (PC₇₁BM) blend film, as well as the aggregation effect on the photovoltaic performance of DBSQ:PC₇₁BM bulk heterojunctions (BHJs). Our finding shows that the aggregation behavior of DBSQ dye in the blend film can be controlled via the proper selection of the processing solvents. For a J-aggregate (head-to-tail molecule alignment) DBSQ:PC₇₁BM active layer based BHJ cells, a power conversion efficiency (PCE) of over 5% can be obtained, which is 75% higher than that of the H-aggregate (parallel molecule packing) active layer based BHJ cells. Our results indicate that the processing solvent controlled J-aggregation formation shall be considered as effective approach to tune the optical and electrical properties of thin films for high-performance BHJ solar cells.

在这项工作中，我们系统地研究了一种DBSQ中的方酸染料，即2,4-双[4-（N，N-二丁基氨基）-2,6-二羟基苯基]方酸（DBSQ）的加工溶剂依赖性聚集行为： [6,6]-苯基-C71-丁酸甲酯（PC ₇₁ BM）混合膜，以及对DBSQ：PC ₇₁ BM本体异质结（BHJ）的光伏性能的聚集效应。我们的发现表明，DBSQ的聚集行为在共混物膜染料可经由处理溶剂的适当选择被控制。对于J聚集体（头对尾分子比对）DBSQ：PC ₇₁基于BM活性层的BHJ电池，可以获得超过5％的功率转换效率（PCE），比基于H骨料（平行分子堆积）的BHJ电池的功率转换效率高75％。我们的结果表明，加工溶剂控制的J聚集形成应被认为是调整高性能BHJ太阳能电池薄膜光学和电学性质的有效方法。