Department of Materials Science and Engineering, University of Tennessee, Knoxville, 37996, USA.
Phys Chem Chem Phys. 2014 Mar 14;16(10):4971-6. doi: 10.1039/c3cp54908a.
The accumulation of dissociated charge carriers plays an important role in reducing the loss occurring in organic solar cells. We find from light-assisted capacitance measurements that the charge accumulation inevitably occurred at the electrode and photovoltaic layer interface for bulk-heterojunction ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al solar cells. Our results indicate, for the first time through impedance measurements, that the charge accumulation exists at the anode side of the device, and more importantly, we successfully identify the type of charge accumulated. Further study shows that the charge accumulation can significantly affect open circuit voltage and short circuit current. As a result, our experimental results from light assisted capacitance measurements provide a new understanding of the loss in open-circuit voltage and short-circuit photocurrent based on charge accumulation. Clearly, controlling charge accumulation presents a new mechanism to improve the photovoltaic performance of organic solar cells.
在有机太阳能电池中，非定域电荷载流子的积累对降低能量损耗起着重要作用。我们通过光辅助电容测量发现，在本体异质结 ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al 太阳能电池中，电荷不可避免地在电极和光伏层界面处积累。通过阻抗测量，我们首次表明电荷在器件的阳极侧积累，这一结果至关重要，同时我们还成功地确定了积累电荷的类型。进一步的研究表明，电荷积累会显著影响开路电压和短路电流。因此，我们通过光辅助电容测量得到的实验结果，为基于电荷积累的开路电压和短路光电流损耗提供了新的认识。显然，控制电荷积累为提高有机太阳能电池的光伏性能提供了新的机制。
