Polythiophene:Perylene Diimide Solar Cells - the Impact of Alkyl-Substitution on the Photovoltaic Performance
Polythiophene:Perylene Diimide Solar Cells - the Impact of Alkyl-Substitution on the Photovoltaic Performance
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DOI：
10.1002/aenm.201000006
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发表时间：
2011-03-18
影响因子：
27.8
通讯作者：
Laquai, Frederic
中科院分区：
文献类型：
--
作者：
Kamm, Valentin;Battagliarin, Glauco;Laquai, Frederic
光伏参数，即，使用二萘嵌苯二酰亚胺（PDI）衍生物作为电子受体的本体异质结太阳能电池的短路电流、开路电压和器件填充因子通常远低于理论上预期的值，原因仍然不完全清楚。这篇文章表明，区域规则的聚（3-己基噻吩）（rr-P3 HT）和PDI分子的共混物膜的光伏特性得到改善后，使用核心烷基化的PDI衍生物，而不是经常使用的N-烷基化的PDI分子。观察到通过使用核烷基化的PDI衍生物使P3 HT：PDI太阳能电池的功率转换效率加倍，导致P3 HT：PDI太阳能电池在AM 1.5太阳照射下的前所未有的0.5%的功率转换效率。此外，新的PDI衍生物的光学性质进行了比较，两个标准的唯一的N-烷基化的PDI衍生物的稳态和时间分辨的光致发光光谱在溶液和固体状态。实验表明，在固态下的聚集决定了所有PDI衍生物的物理性质。然而，聚集体的发射能量和激发态寿命明显地受到烷基取代模式的影响，通过其对PDI分子的堆积的影响。X-射线衍射实验前后的PDI：聚苯乙烯和PDI：P3 HT共混物的热退火揭示了微妙的差异，在包装特性的不同的PDI衍生物，有问题的是，P3 HT订购抑制所有的PDI衍生物。
The photovoltaic parameters, i.e., the short-circuit current, open-circuit voltage and device fill factor, of bulk heterojunction solar cells that use perylene diimide (PDI) derivatives as electron acceptors are often far below the theoretically expected values for reasons still not entirely understood. This article demonstrates that the photovoltaic characteristics of blend films of regioregular poly(3-hexylthiophene) (rr-P3HT) and PDI molecules are improved upon using a core-alkylated PDI derivative instead of the often used N-alkylated PDI molecules. A doubling of the power conversion efficiency of P3HT:PDI solar cells by using the core-alkylated PDI derivative is observed leading to an unprecedented power conversion efficiency of 0.5% for a P3HT:PDI solar cell under AM1.5 solar illumination. Furthermore, the optical properties of the novel PDI derivative are compared to two standard exclusively N-alkylated PDI derivatives by steady-state and time-resolved photoluminescence spectroscopy in solution and solid state. The experiments reveal that aggregation in the solid state determines the photophysics of all PDI derivatives. However, the emission energy and excited state lifetime of the aggregates are clearly influenced by the alkyl-substitution pattern through its effect on the packing of the PDI molecules. X-ray diffraction experiments before and after thermal annealing of PDI:polystyrene and PDI:P3HT blends reveal subtle differences in the packing characteristics of the different PDI derivatives and, problematically, that P3HT ordering is suppressed by all of the PDI derivatives.