Synooka Olesia, Kretschmer Florian, Hager Martin D, Himmerlich Marcel, Krischok Stefan, Gehrig Dominik, Laquai Frédéric, Schubert Ulrich S, Gobsch Gerhard, Hoppe Harald
Institut für Physik and Institut für Mikro- und Nanotechnologien, Technische Universität Ilmenau , Langewiesener Strasse 22, 98693 Ilmenau, Germany.
ACS Appl Mater Interfaces. 2014 Jul 23;6(14):11068-81. doi: 10.1021/am503284b. Epub 2014 Jun 30.
The influence of various polar solvent additives with different dipole moments has been investigated since the performance of a photovoltaic device comprising a donor-acceptor copolymer (benzothiadiazole-fluorene-diketopyrrolopyrrole (BTD-F-DKPP)) and phenyl-C60-butyric acid methyl ester (PCBM) was notably increased. A common approach for controlling bulk heterojunction morphology and thereby improving the solar cell performance involves the use of solvent additives exhibiting boiling points higher than that of the surrounding solvent in order to allow the fullerene to aggregate during the host solvent evaporation and film solidification. In contrast to that, we report the application of polar solvent additives with widely varied dipole moments, where intentionally no dependence on their boiling points was applied. We found that an appropriate amount of the additive can improve all solar cell parameters. This beneficial effect could be largely attributed to a modification of the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-active layer interface within the device layer stack, which was successfully reproduced for polymer solar cells based on the commonly used PCDTBT (poly[N-900-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)]) copolymer.
由于包含供体-受体共聚物（苯并噻二唑-芴-二酮吡咯并吡咯（BTD-F-DKPP））和苯基-C60-丁酸甲酯（PCBM）的光伏器件的性能显著提高，因此研究了具有不同偶极矩的各种极性溶剂添加剂的影响。控制本体异质结形态从而提高太阳能电池性能的常用方法包括使用沸点高于周围溶剂的溶剂添加剂，以便在主体溶剂蒸发和薄膜固化过程中使富勒烯聚集。与此相反，我们报道了应用偶极矩差异很大的极性溶剂添加剂，其中有意不考虑它们的沸点。我们发现适量的添加剂可以改善所有太阳能电池参数。这种有益效果很大程度上可归因于器件层堆叠内聚（3,4-乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT:PSS）-活性层界面的改性，这一结果基于常用的聚[N-900-十七烷基-2,7-咔唑-alt-5,5-（40,70-二-2-噻吩基-20,10,30-苯并噻二唑）]（PCDTBT）共聚物成功地在聚合物太阳能电池中得到了重现。
