Determination of Quasi-Fermi Levels across Illuminated Organic Donor/Acceptor Heterojunctions by Kelvin Probe Force Microscopy
Determination of Quasi-Fermi Levels across Illuminated Organic Donor/Acceptor Heterojunctions by Kelvin Probe Force Microscopy
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DOI：
10.1021/ja2034574
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发表时间：
2011-09-07
影响因子：
15
通讯作者：
Frisbie, C. Daniel
中科院分区：
文献类型：
--
作者：
Ellison, David J.;Kim, Jung Yong;Frisbie, C. Daniel
用开尔文探针力显微镜(KFM)测量了氧化铟锡/有机和施主/受主异质结在黑暗和白光照射下的电化学势。我们发现，在这些异质结上产生的光电压与施主和受主的HOMO和LUMO能级之间的差异有很强的相关性，也非常接近于在完成的太阳能电池中测量的开路电压。这些结果表明，KFM跟踪了光激发下施主和受主层中的费米能级位置。总体而言，这些结果证明了KFM在了解平面-异质结有机太阳能电池中跨有源层的电势分布方面的实用性。
Using Kelvin probe force microscopy (KFM), we have measured the electrochemical potentials across indium tin oxide/organic and donor/acceptor heterojunctions in the dark and under illumination with white light. We have found that the photovoltage generated across these heterojunctions is strongly correlated with the difference between the respective HOMO and LUMO levels of the donor and acceptor and also very closely approximates measured open-circuit voltages in completed solar cells. These results imply that KFM tracks the Fermi level positions within the donor and acceptor layers under photoexcitation. Overall, these results demonstrate the utility of KFM for understanding potential profiles across active layers in planar-heterojunction organic solar cells.