Phase-Dependent Photocurrent Generation in Polymer/Fullerene Bulk Heterojunction Solar Cells
Phase-Dependent Photocurrent Generation in Polymer/Fullerene Bulk Heterojunction Solar Cells
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DOI：
10.1021/jp208466t
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发表时间：
2011-11-10
影响因子：
3.7
通讯作者：
McNeill, Christopher R.
中科院分区：
文献类型：
--
作者：
Brenner, Thomas J. K.;Li, Zhe;McNeill, Christopher R.
电压依赖性白光偏置的外量子效率（EQE）的测量被用来比较相对电压的依赖性，光电流产生的聚合物和富勒烯相的聚合物体异质结太阳能电池。通过测量作为施加的偏压的函数的EQE光谱，电压，EQE光谱的形状的依赖性变化可以被检测和比较，与聚合物和富勒烯的吸收曲线。研究了几种高效体系，包括聚（3-己基噻吩）：PC 60 BM（[6，6]-苯基-C-61-丁酸甲酯）共混物和低带隙聚合物与PC 70 BM的共混物。对于一些系统（但不是全部），电压依赖性，但光强度无关的EQE光谱的形状的变化，观察到起源于聚合物和富勒烯吸收的光电流的电压依赖性的差异。对于一个系统，发现富勒烯吸收后光电流产生的电压依赖性更强，而对于另一个系统，观察到聚合物吸收后光电流产生的电压依赖性更强。我们将这种效应归因于电荷转移后立即形成的界面电子-空穴对的特性差异，对初始激子态的性质和界面的构象性质的差异敏感。
Voltage-dependent white-light bias external quantum efficiency (EQE) measurements are employed to compare the dependence of relative voltage-photocurrent generation of polymer and fullerene phases in polymer bulk heterojunction solar cells. By measuring EQE spectra as a function of applied bias, voltage,dependent changes in the shape of EQE spectra can be detected and compared, with the absorption profiles of polymer and fullerene. Several high-efficiency systems studied including poly(3-hexylthiophene):PC60BM ([6,6]-phenyl-C-61-butyric acid methyl ester) blends and blends of low band gap polymers with PC70BM. For a number, of systems (but not all), voltage-dependent-but light-intensity-independent changes in the shape of the EQE spectrum are observed that originate from differences in the voltage dependence of photocurrent for polymer and fullerene absorption. For one system, a stronger voltage-dependence of photocurrent generation following fullerene absorption is found, whereas for another system a stronger voltage-dependence of photocurrent generation following polymer absorption is observed We attribute this effect to differences in the character of interfacial electron-hole pairs formed immediately after charge transfer, sensitive to differences in the nature of the initial excitonic state and the conformation nature of the interface.