Suppressing the Surface Recombination and Tuning the Open-Circuit Voltage of Polymer/Fullerene Solar Cells by Implementing an Aggregative Ternary Compound.
Suppressing the Surface Recombination and Tuning the Open-Circuit Voltage of Polymer/Fullerene Solar Cells by Implementing an Aggregative Ternary Compound.
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DOI：
10.1021/acsami.8b09174
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发表时间：
2018-08
影响因子：
9.5
通讯作者：
D. Galli;Nicola Gasparini;M. Forster;Anika Eckert;Christian Widling;M. Killian;Apostolos Avgeropoulos;V. Gregoriou;U. Scherf;C. Chochos;C. Brabec;T. Ameri
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文献类型：
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作者：
D. Galli;Nicola Gasparini;M. Forster;Anika Eckert;Christian Widling;M. Killian;Apostolos Avgeropoulos;V. Gregoriou;U. Scherf;C. Chochos;C. Brabec;T. Ameri
在这项工作中，我们提出了一种基于二噻吩基噻吩并噻二唑单元（称为SM1）的新型小分子，作为三元共混有机太阳能电池中的有效成分，以改变界面处的空穴提取。我们的研究结果表明，SM1 抑制表面复合并提高开路电压 (Voc)。通过在由聚（3-己基噻吩）（P3HT）和[6,6]-苯基-C61-丁酸甲酯（PCBM）组成的主体系统中引入SM1，我们获得了高达0.75 V的Voc值和大于70%的三元共混物填充因子。因此，与 P3HT:PCBM 二进制器件相比，功率转换效率提高了约 30%。有趣的是，近红外区域的外部量子效率和吸收光谱并未显示出 SM1 在干燥薄膜中的任何贡献。相反，小分子的添加通过减少表面复合损失来提高开路电压。为了阐明复合过程，我们进行了傅里叶变换光电流光谱和阻抗光谱测量。这项工作表明，三元概念还可以具有光敏化以外的功能，甚至可以充当形态导向剂或界面改性剂。
In this work, we present a novel small molecule based on dithienylthienothiadiazole units (named SM1) acting as an efficient component in ternary blend organic solar cells to modify the hole extraction at the interface. Our findings show that the SM1 suppresses the surface recombination and enhances the open-circuit voltage ( Voc). By introducing SM1 in a host system composed of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl- C61-butyric acid methyl ester (PCBM), we obtained Voc values of up to 0.75 V and fill factors larger than 70% for the ternary blends. As a consequence, the power conversion efficiency is improved by about 30% compared to P3HT:PCBM binary devices. Interestingly, external quantum efficiency and absorption spectra in the near-infrared region do not show any contribution of SM1 in dried films. Instead, the addition of the small molecule improves the Voc by reducing the surface recombination losses. To shed light on the recombination processes, we carried out Fourier-transform photocurrent spectroscopy and impedance spectroscopy measurements. This work shows that the ternary concept can also have functionalities other than photosensitization and can even act as a morphology-directing agent or an interface modifier.