The effect of side-chain length on regioregular poly[3-(4-n-alkyl)phenylthiophene]/PCBM and ICBA polymer solar cells
作者:Chul-Hee Cho、Hyeong Jun Kim、Hyunbum Kang、Tae Joo Shin、Bumjoon J. Kim
DOI:10.1039/c2jm31371e
日期:——
The photovoltaic, charge transport, light absorption and morphology properties of a series of poly[3-(4-n-alkyl)phenylthiophene] (PAPT):acceptor (phenyl-C61-butyric acid methyl ester (PCBM) or indene-C60 bisadduct (ICBA)) blend films are reported as a function of alkyl side-chain length. Regioregular poly[3-(4-n-butyl)phenylthiophene] (PBPT), poly[3-(4-n-hexyl)phenylthiophene] (PHPT), poly[3-(4-n-octyl)phenylthiophene] (POPT), and poly[3-(4-n-decyl)phenylthiophene] (PDPT) were successfully synthesized by a modified Grignard metathesis (GRIM) polymerization method. The effects of the alkyl side-chain length on the optical, electrochemical and structural properties of the polymers were carefully investigated to establish a relationship between the molecular structure and device function. Bulk heterojunction solar cells made of PAPTs blended with either PCBM or ICBA showed a strong photovoltaic property dependence on the alkyl side-chain length. Among all PAPTs used in this study, the best performance was observed in PHPT-based devices. This is the first report of the use of PHPT in polymer solar cells. In addition, PAPT devices blended with ICBA generally showed higher open-circuit voltages (Voc) and power conversion efficiencies than PCBM-based devices. For example, a PHPT:ICBA photovoltaic device showed a Voc of 0.79 V and a power conversion efficiency of 3.7%, which is the highest performance reported thus far using PAPT polymers. While the optical properties of PAPT/electron acceptor films exhibit the strongest effect on the short-circuit current of the devices, a balance between the optical, electrical and morphological properties of blended films caused by the alkyl side-chain length determines the overall photovoltaic performance of these devices. Therefore, our work provides a fundamental understanding of the molecular structure–device function relationship, especially with respect to changes in the alkyl side-chain length in conjugated polymers.
报道了一系列聚[3-(4-n-烷基)苯硫烯] (PAPT):受体(苯-C61-丁酸甲酯(PCBM)或茚-C60双加成物(ICBA))混合薄膜的光伏、载流子传输、光吸收和形态特性,作为烷基侧链长度的函数。通过改进的Grignard重排(GRIM)聚合方法成功合成了规整聚[3-(4-n-丁基)苯硫烯](PBPT)、聚[3-(4-n-己基)苯硫烯](PHPT)、聚[3-(4-n-辛基)苯硫烯](POPT)和聚[3-(4-n-癸基)苯硫烯](PDPT)。仔细研究了烷基侧链长度对聚合物的光学、电化学和结构特性的影响,以建立分子结构与器件功能之间的关系。由PAPT与PCBM或ICBA混合制成的块状异质结太阳能电池表现出光伏性能对烷基侧链长度的强依赖性。在本研究中使用的所有PAPT中,PHPT基器件表现出最佳性能。这是首次报告PHPT在聚合物太阳能电池中的应用。此外,与PCBM基器件相比,PAPT与ICBA混合的器件通常显示出更高的开路电压(Voc)和功率转换效率。例如,PHPT:ICBA光伏器件显示出Voc为0.79 V,功率转换效率为3.7%,这是迄今为止使用PAPT聚合物所报告的最高性能。虽然PAPT/电子受体薄膜的光学特性对器件的短路电流影响最大,但烷基侧链长度引起的混合薄膜的光学、电气和形态特性之间的平衡决定了这些器件的整体光伏性能。因此,我们的研究为分子结构与器件功能关系提供了基础理解,特别是关于共轭聚合物中烷基侧链长度变化的影响。