Efficient solar cells based on a new phthalimide-based donor–acceptor copolymer semiconductor: morphology, charge-transport, and photovoltaic properties
Efficient solar cells based on a new phthalimide-based donor–acceptor copolymer semiconductor: morphology, charge-transport, and photovoltaic properties
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DOI：
10.1039/b900073a
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发表时间：
2009-07
影响因子：
--
通讯作者：
H. Xin;Xugang Guo;F. S. Kim;Guoqiang Ren;M. Watson;S. Jenekhe
中科院分区：
文献类型：
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作者：
H. Xin;Xugang Guo;F. S. Kim;Guoqiang Ren;M. Watson;S. Jenekhe
系统地研究了基于新型低带隙供体-受体共聚物、聚(N-（十二烷基）-3,6-二（4-十二烷基氧基噻吩-2-基）酞酰亚胺（PhBT12）和富勒烯衍生物[6,6]-苯基c61 -丁酸甲酯（PC61BM）或[6,6]-苯基c71 -丁酸甲酯（PC71BM）共混物的体异质结太阳能电池。研究发现，PhBT12/富勒烯共混薄膜具有纳米级晶体形态，其空穴的空间电荷限制迁移率高达4.0 × 10−4 cm2/Vs，无需热退火，可制成中等效率的器件。PhBT12/PC71BM混合器件的功率转换效率为2.0%，电流密度为6.43 mA/cm2，填充系数为0.55。然而，热退火（120°C） PhBT12/富勒烯共混器件的光伏性能可以忽略不计，因为共混物的微米级相分离是由于长侧链。我们期望通过改变聚合物侧链长度和器件加工工艺可以获得更好的光伏性能。这些结果表明，以PhBT12为代表的邻苯二甲酸亚胺基给受体共聚物半导体是一种很有前途的低带隙材料，可用于开发高效的体异质结太阳能电池。
Bulk heterojunction solar cells based on blends of the new low band gap donor–acceptor copolymer, poly(N-(dodecyl)-3,6-bis(4-dodecyloxythiophen-2-yl)phthalimide) (PhBT12), and fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) were systematically investigated. The PhBT12/fullerene blend films were found to exhibit a crystalline nanoscale morphology with space-charge-limited mobility of holes as high as 4.0 × 10−4 cm2/Vs without thermal annealing, leading to moderately efficient devices. The performance of the solar cells varied significantly with PhBT12/fullerene composition, reaching a power conversion efficiency of 2.0% with a current density of 6.43 mA/cm2 and a fill factor of 0.55 for the 1:1 PhBT12/PC71BM blend devices. However, thermally annealed (120 °C) PhBT12/fullerene blend devices had negligible photovoltaic properties due to micrometer scale phase separation of the blends which is attributed to the long side chains. We expect that better photovoltaic performance can be achieved by modifying the polymer side chain length and the device processing as well. These results show that phthalimide-based donor–acceptor copolymer semiconductors, exemplified by PhBT12, are promising low band gap materials for developing efficient bulk heterojunction solar cells.