Polymer/Polymer Blend Solar Cells Improved by Using High-Molecular-Weight Fluorene-Based Copolymer as Electron Acceptor
Polymer/Polymer Blend Solar Cells Improved by Using High-Molecular-Weight Fluorene-Based Copolymer as Electron Acceptor
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DOI：
10.1021/am300623f
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发表时间：
2012-07-01
影响因子：
9.5
通讯作者：
Miyake, Kunihito
中科院分区：
文献类型：
--
作者：
Mori, Daisuke;Benten, Hiroaki;Miyake, Kunihito
对于用聚（3-己基噻吩）（P3 HT，电子供体）和聚[2，7（9，9-双十二烷基芴）-alt-5，5-（4 '，7'-双（2-噻吩基）-2 '，1'，3 '-苯并噻二唑）]（PF 12 TBT，电子受体）的共混物制成的所有聚合物太阳能电池，已经实现了2.7%的最高功率转换效率（PCE）。P3 HT/PF 12 TBT太阳能电池的PCE从1.9%增加到2.7%，PF 12 TBT的分子量（M-w）从8500增加到78 000 g mol（-1）。在具有高分子量PF 12 TBT的器件中，即使在高退火温度下也保持有效的电荷产生，这是因为在激子扩散的长度尺度上的小相分离，这是由于玻璃化转变温度（T-g）的增加和PF 12 TBT链在T-g以上的降低的扩散迁移率。另一方面，有效的电荷传输也是通过形成PF 12 TBT富集域的互连网络来实现的，这是由PF 12 TBT的高分子量和P3 HT富集域中P3 HT链的有序化来促进的，这是高温退火的结果。因此，当使用高分子量PF 12 TBT时，通过热退火可以获得支持有效电荷产生以及电荷传输的最佳共混物形态，因此，实现了迄今为止报道的全聚合物太阳能电池的最高PCE。
The highest power conversion efficiency (PCE) of 2.7% has been achieved for all polymer solar cells made with a blend of poly(3-hexylthiophene) (P3HT, electron donor) and poly[2,7(9,9-didodecylfluorene)-alt-5,5-(4',7'-bis(2-thienyl)-2',1',3'-benzo-thiadiazole)] (PF12TBT, electron acceptor). The PCE of the P3HT/PF12TBT solar cells increases from 1.9% to 2.7% with an increase in the molecular weight (M-w) of PF12TBT from 8500 to 78 000 g mol(-1). In a device with high-molecular-weight PF12TBT, efficient charge generation is maintained even at high annealing temperatures because of the small phase separation on the length scale of exciton diffusion due to an increase in the glass transition temperature (T-g) and a reduced diffusional mobility of the PF12TBT chains above T-g. On the other hand, efficient charge transport is also achieved through the formation of interconnected networks of PF12TBT-rich domains, which is facilitated by the high molecular weight of PF12TBT, and the ordering of P3HT chains in P3HT-rich domains, which is a result of high temperature annealing. Thus, when high-molecular-weight PF12TBT is used, an optimal blend morphology that supports efficient charge generation as well as charge transport can be obtained by thermal annealing, and consequently, the highest PCE reported so far for an all polymer solar cell is achieved.