Synthesis and morphological studies of a poly(5,6-difluorobenzo-2,1,3-thiadiazole-4,7-diyl-alt-quaterchalcogenophene) copolymer with 7.3% polymer solar cell efficiency
Synthesis and morphological studies of a poly(5,6-difluorobenzo-2,1,3-thiadiazole-4,7-diyl-alt-quaterchalcogenophene) copolymer with 7.3% polymer solar cell efficiency
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DOI：
10.1039/c4py00777h
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发表时间：
2014-10
影响因子：
4.6
通讯作者：
Jhong‐Sian Wu;J. Jheng;Jen-Yun Chang;Yu‐Ying Lai;Kuan-Yi Wu;Chien-Lung Wang;Chain‐Shu Hsu
中科院分区：
文献类型：
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作者：
Jhong‐Sian Wu;J. Jheng;Jen-Yun Chang;Yu‐Ying Lai;Kuan-Yi Wu;Chien-Lung Wang;Chain‐Shu Hsu
为了得到一种具有较小光学带隙的poly(5，6-difluorobenzo-2，1，3-thiadiazole-4，7-diyl-alt-quaterchalcogenophene)(P(FBT-ALT-CP4))共聚物，并在P(FBT-ALT-CP4)：PC71BM聚合物太阳电池中获得高短路电流，合成了含硒-2，5-二基(-Se-)π桥的P(FBT-ALT-Se2Th2)。P(FBT-ALT-Se2Th2)的Eg为1.56 eV，在溶液中呈强聚集状态。广角X射线衍射(WAXD)和掠入射X射线衍射(GI-XRD)结果表明，P(FBT-ALT-Se2Th2)在衬底上具有较高的固相有序度和择优取向。它在有机场效应晶体管(OFET)中提供了0.36cm2V−1 S−1的高空穴迁移率(OFET H)。P(FBT-ALT-Se2Th2)：PC71BM薄膜中P(FBT-ALT-Se2Th2)的强烈聚集倾向导致了较大的偏析磁区，高分辨电子显微镜(HR-TEM)图像显示了这一点。加入体积分数为8%的1-氯代萘(1-CN)有效地抑制了聚集体的聚集，使活性层形态更加均匀。改进后的形貌增强了PSCs的JSC。在倒置P(−-ALT-Se2Th2)：PC71BM PSCs中，获得了7.34%的光电转换效率、0.70V的伏安电压、15.8 mA cm−2的JSC值和66.4%的FF值。根据FBT-ALT-Se2Th2重复单元的理论计算结果，P(FBT-ALT-Se2Th2)的强聚集可能与其更直的共轭骨架有关。
To obtain a poly(5,6-difluorobenzo-2,1,3-thiadiazole-4,7-diyl-alt-quaterchalcogenophene) (P(FBT-alt-CP4)) copolymer with a small optical band gap (Eg), and to achieve high short-circuit current (Jsc) in the P(FBT-alt-CP4) : PC71BM polymer solar cells (PSCs), P(FBT-alt-Se2Th2), which contains selenophene-2,5-diyl (–Se–) π-bridges, was synthesized. P(FBT-alt-Se2Th2) shows a Eg of 1.56 eV and is strongly aggregated in solution. Wide angle X-ray diffraction (WAXD) and grazing incidence X-ray diffraction (GI-XRD) results revealed the high solid-state order of P(FBT-alt-Se2Th2) and its edge-on orientation on the substrate. It delivered a high hole mobility (μh) of 0.36 cm2 V−1 s−1 in organic field-effect transistors (OFETs). The strong aggregation tendency of P(FBT-alt-Se2Th2) caused large segregation domains in the P(FBT-alt-Se2Th2) : PC71BM thin film, as is seen in the high-resolution transmission electron microscopy (HR-TEM) images. The addition of 8 vol% of 1-chloronaphthalene (1-CN) effectively suppressed the aggregation and led to more homogeneous active layer morphology. The improved morphology enhanced the Jsc of the PSCs. A superior PCE of 7.34% with a Voc of 0.70 V, a Jsc of 15.8 mA cm−2, and a FF of 66.4% was achieved in the inverted P(FBT-alt-Se2Th2) : PC71BM PSCs. The strong aggregation of P(FBT-alt-Se2Th2) is likely related to its more straight conjugated backbone according to the theoretical calculation results of the FBT-alt-Se2Th2 repeat unit.