Fullerene-linked tetrabenzoporphyrins for solution-processed organic photovoltaics: flexible vs. rigid linkers
Fullerene-linked tetrabenzoporphyrins for solution-processed organic photovoltaics: flexible vs. rigid linkers
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DOI：
10.1039/c6ta06599f
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发表时间：
2016-10
影响因子：
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通讯作者：
Yuto Tamura;Daiki Kuzuhara;Mitsuharu Suzuki;H. Hayashi;N. Aratani;H. Yamada
中科院分区：
文献类型：
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作者：
Yuto Tamura;Daiki Kuzuhara;Mitsuharu Suzuki;H. Hayashi;N. Aratani;H. Yamada
用前驱体方法可以进行逐层结构的溶液处理，在该方法中，不可溶或低溶解度目标材料的可溶前驱体被旋涂在衬底上，并通过加热转化为不可溶半导体薄膜。我们尝试使用溶液过程构建p-i-n结构(p：p-层；i：中间层，p-和n-材料的混合物；n：n-层)。为了增加供体-受体的界面面积，我们合成了共价连接的供体-受体化合物四苯并卟啉(BP)-富勒烯(C60)二元组。为了研究给体和受体单元的共价连接对膜形态和OPV性能的影响，用柔性或刚性连接物(f-BP-C60或r-BP-C60)连接BP和富勒烯单元。通过[2+2]和[2+1+1]缩合反应，以单中位取代苯二酚为原料，进行了新的合成路线。在CH2Cl2中，f-BP-C60的C60单元对BP的分子内荧光猝灭效率高于r-BP-C60的分子内荧光猝灭效率，这是由于连接物的柔性以及C60单元与BP单元的位置接近所致。用空间电荷限制电流(SCLC)技术测量了r-BP-C60薄膜的载流子迁移率，结果表明r-BP-C60薄膜的载流子迁移率优于f-BP-C60薄膜，并且r-BP-C60薄膜的体异质结OPV性能优于f-BP-C60薄膜。尽管与f-BP-C60相比，r-BP-C60器件具有更好的OPV性能，但对于p层、i层和n层，含有BP、f-BP-C60和[6，6]-苯基-C61-丁酸甲酯(PCBM)的p-i-n器件的短路电流密度(JSC)和Ff都好于以r-BP-C60为I层的器件。薄膜的AFM图像和OPV性能表明，柔性的f-BP-C60可以用于高结晶度的BP薄膜上的I层，因为f-BP-C60使BP薄膜的粗糙度变平，并且通过光滑的界面改善了器件的电学性能。
Solution processing of a layer-by-layer structure is possible with a precursor approach, in which the soluble precursors of the insoluble or low-solubility target materials are spin-coated on the substrate and converted to insoluble semiconducting films by heating. We attempted to construct a p–i–n structure (p: p-layer; i: interlayer, a mixture of p- and n-materials; n: n-layer) using a solution process. To increase the donor–acceptor interface area, we synthesized covalently linked donor–acceptor compounds, tetrabenzoporphyrin (BP)–fullerene (C60) dyad. To investigate the effect of the covalent connection of the donor and acceptor units on the film morphology and on the OPV performances, the BP and fullerene units were connected by a flexible or rigid linker (f-BP–C60 or r-BP–C60). To synthesize these dyads, new synthetic routes with mono-meso-substituted BPs using [2 + 2] and [2 + 1 + 1] condensation reactions were performed. The intramolecular fluorescence quenching efficiency of BP by the C60 unit of f-BP–C60 was higher than that of r-BP–C60 in CH2Cl2 because of the flexibility of the linker and the close location of the C60 unit to the BP unit. The carrier mobility in the r-BP–C60 film measured by the space-charge-limited-current (SCLC) technique was better than that of the f-BP–C60 film, and the bulk heterojunction (BHJ)-type OPV performance of the r-BP–C60 film was better than that of the f-BP–C60 film. In spite of the superior OPV performance of the r-BP–C60 device compared to the f-BP–C60, the short circuit current density (JSC) and FF of the p–i–n device with BP, f-BP–C60, and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) for p-, i- and n-layers was better than the device with r-BP–C60 as the i-layer. AFM images of the layers and OPV performances suggested that the flexible f-BP–C60 is suitable for the i-layer on the highly crystalline BP film because the roughness of the BP film is leveled by the f-BP–C60, and the electric properties of the device are improved by the smooth interface.