The Crucial Influence of Fullerene Phases on Photogeneration in Organic Bulk Heterojunction Solar Cells
The Crucial Influence of Fullerene Phases on Photogeneration in Organic Bulk Heterojunction Solar Cells
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DOI：
10.1002/aenm.201400922
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发表时间：
2014-12
影响因子：
27.8
通讯作者：
Andreas Zusan;K. Vandewal;B. Allendorf;N. H. Hansen;J. Pflaum;A. Salleo;V. Dyakonov;C. Deibel
中科院分区：
文献类型：
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作者：
Andreas Zusan;K. Vandewal;B. Allendorf;N. H. Hansen;J. Pflaum;A. Salleo;V. Dyakonov;C. Deibel
共轭聚合物聚（2，5-双（3-十六烷基噻吩-2-基）噻吩并[3，2-B]噻吩）（pBTTT-C16）允许通过改变受体类型和分数来系统地调节共混物形态，使其成为研究有机本体异质结太阳能电池中基本过程的非常合适的结构模型。为了分析插层和纯富勒烯域对电荷载流子光生的作用，在具有各种化学计量的pBTTT-C16：[6，6]-苯基-C61-丁酸甲酯（PC61 BM）太阳能电池上进行时间延迟收集场（TDCF）测量和傅里叶变换光电流谱（FTPS）。多余的光子能量对光生沿着具有较弱的场依赖性的光生在增加fullerene loadings. The调查结果被分配到解离通过热化电荷转移（CT）状态支持的增强的电子离域沿着空间扩展的PC61 BM纳米相，形成除了一个双分子晶体（BMC）的PC61 BM丰富的共混物。通过对非插层pBTTT-C16：bisPC 61 BM共混物进行TDCF测量，进一步研究了电荷载流子从BMC到纯域的高效转移。它们揭示了类似于1：4 PC61 BM共混物的场依赖性电荷产生，表明纯受体相的存在是有效的场独立CT解离的主要驱动力。
The conjugated polymer, poly(2,5‐bis(3‐hexadecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) (pBTTT‐C16), allows a systematic tuning of the blend morphology by varying the acceptor type and fraction, making it a well‐suited structural model for studying the fundamental processes in organic bulk heterojunction solar cells. To analyze the role of intercalated and pure fullerene domains on charge carrier photogeneration, time delayed collection field (TDCF) measurements and Fourier‐transform photocurrent spectroscopy (FTPS) are performed on pBTTT‐C16:[6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) solar cells with various stoichiometries. A weak influence of excess photon energy on photogeneration along with a photogeneration having a weaker field dependence at increasing fullerene loading is found. The findings are assigned to a dissociation via thermalized charge transfer (CT) states supported by an enhanced electron delocalization along spatially extended PC61BM nanophases that form in addition to a bimolecular crystal (BMC) for PC61BM rich blends. The highly efficient transfer of charge carriers from the BMC into the pure domains are studied further by TDCF measurements performed on non‐intercalated pBTTT‐C16:bisPC61BM blends. They reveal a field dependent charge generation similar to the 1:4 PC61BM blend, demonstrating that the presence of pure acceptor phases is the major driving force for an efficient, field independent CT dissociation.