Modeling the current-voltage characteristics of bilayer polymer photovoltaic devices
Modeling the current-voltage characteristics of bilayer polymer photovoltaic devices
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DOI：
10.1103/physrevb.67.075205
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发表时间：
2003-02-15
影响因子：
3.7
通讯作者：
Greenham, NC
中科院分区：
文献类型：
--
作者：
Barker, JA;Ramsdale, CM;Greenham, NC
我们建立了一个数值模型来预测双层共轭聚合物光伏器件的电流-电压曲线。该模型考虑了电荷的光产生、注入、漂移、扩散和复合，并包括空间电荷对器件内电场的影响。聚合物-聚合物界面处的电荷分离导致形成束缚极化子对，这些极化子对可能重组单分子或被解离成自由电荷，并且我们建立了解离率的场依赖表达式。我们发现短路量子效率是由极化子对离解和复合之间的竞争决定的。该模型显示了开路电压对入射强度的对数依赖关系，如实验所见。这个额外的强度相关电压来自于产生漂移电流所需的场，该漂移电流平衡了由于载流子从界面扩散而产生的电流。
We have developed a numerical model to predict the current-voltage curves of bilayer conjugated polymer photovoltaic devices. The model accounts for charge photogeneration, injection, drift, diffusion, and recombination, and includes the effect of space charge on the electric field within the device. Charge separation at the polymer-polymer interface leads to the formation of bound polaron pairs which may either recombine monomolecularly or be dissociated into free charges, and we develop expressions for the field dependence of the dissociation rate. We find that the short-circuit quantum efficiency is determined by the competition between polaron pair dissociation and recombination. The model shows a logarithmic dependence of the open-circuit voltage on the incident intensity, as seen experimentally. This additional intensity-dependent voltage arises from the field required to produce a drift current that balances the current due to diffusion of carriers away from the interface.