Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells
Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells
复制标题
体异质结有机太阳能电池中电压相关光电流和暗电流的分析模型
DOI：
10.3390/en9060412
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发表时间：
2016
期刊：
影响因子：
3.2
通讯作者：
M. Z. Kabir
中科院分区：
文献类型：
--
作者：
M. Saleheen;Salman M. Arnab;M. Z. Kabir
通过考虑Shockley-Read-Hall（SRH）复合过程，求解电子和空穴的连续性方程，建立了体异质结（BHJ）有机太阳能电池正向暗电流的物理模型.结合指数光子吸收、束缚电子-空穴对（EHPs）的解离效率、载流子俘获以及载流子在光子吸收层中的漂移和扩散，提出了BHJ有机太阳能电池外电压依赖性光电流的解析模型.修正的Braun模型被用来计算电场依赖的解离效率的结合EHPs。考虑实际太阳光谱计算总净电流。通过将模型计算结果与各种已发表的实验结果进行比较，验证了数学模型。我们分析了接触性能，共混物组合物，电荷载流子传输性能（载流子迁移率和寿命），和电池设计上的电流-电压特性的影响。BHJ有机太阳能电池的能量转换效率主要取决于受体层的电子输运性质。本文的研究结果表明，提高载流子传输（迁移率和寿命）和解离的有机共混物中的绑定EHP的BHJ太阳能电池的功率转换效率是至关重要的。
A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ) organic solar cells is developed by considering Shockley-Read-Hall (SRH) recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun’s model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The overall net current is calculated considering the actual solar spectrum. The mathematical models are verified by comparing the model calculations with various published experimental results. We analyze the effects of the contact properties, blend compositions, charge carrier transport properties (carrier mobility and lifetime), and cell design on the current-voltage characteristics. The power conversion efficiency of BHJ organic solar cells mostly depends on electron transport properties of the acceptor layer. The results of this paper indicate that improvement of charge carrier transport (both mobility and lifetime) and dissociation of bound EHPs in organic blend are critically important to increase the power conversion efficiency of the BHJ solar cells.