Extracting Microscopic Device Parameters from Transient Photocurrent Measurements of P3HT:PCBM Solar Cells
Extracting Microscopic Device Parameters from Transient Photocurrent Measurements of P3HT:PCBM Solar Cells
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DOI：
10.1002/aenm.201100709
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发表时间：
2012-06-01
影响因子：
27.8
通讯作者：
Nelson, Jenny
中科院分区：
文献类型：
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作者：
MacKenzie, Roderick C. I.;Shuttle, Christopher G.;Nelson, Jenny
通过在 P3HT:PCBM 太阳能电池的时域漂移扩散模型中包含陷阱限制复合，可以重现明暗条件下电流电压 (JV) 曲线上的实验瞬态光电流 (TPC) 测量。使用同一组模型参数，还可以再现稳态电流电压曲线和电荷提取数据。通过预测开路复合率并将结果与瞬态光电压 (TPV) 测量技术测量的复合率进行比较，对该模型进行了验证。事实证明，该模型结合了传输、载流子捕获、载流子去捕获和重组，能够正确地再现器件动态。通过改变电子和空穴态密度 (DoS) 函数的形状，可以改善模型与实验结果的拟合度。通过在能量空间中离散 DoS 并允许其形状变化，可以紧密拟合 TPC 瞬态并提取电子和空穴 DoS 尾部的形式。研究发现，俘获载流子的DoS可以用一系列能量的高斯偏移来表示。这暂时归因于分子的分子堆积引入的电子无序。
By including trap-limited recombination in a time-domain drift-diffusion model of a P3HT:PCBM solar cell, experimental transient photocurrent (TPC) measurements across the currentvoltage (JV) curve in both the light and the dark can be reproduced. Using the same set of model parameters, the steady-state currentvoltage curves and charge-extraction data are also reproduced. The model is validated by predicting the recombination rate at open circuit and comparing results with the rate as measured by the transient photovoltage (TPV) measurement technique. It is demonstrated that the model, which incorporates transport, carrier trapping, carrier de-trapping, and recombination, is able to reproduce device dynamics correctly. The fit of the model to the experimental results is improved by varying the shape of the electron and hole density of state (DoS) functions. By discretizing the DoS in energy space and allowing its shape to vary, the TPC transients can be closely fitted and the form of the tails of the electron and hole DoS extracted. It is found that the DoS of trapped carriers can be represented by a series of Gaussians offset in energy. This is tentatively attributed to electronic disorder introduced by molecular packing of the molecules.