Influence of Charge Transport Layers on Capacitance Measured in Halide Perovskite Solar Cells
Influence of Charge Transport Layers on Capacitance Measured in Halide Perovskite Solar Cells
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DOI：
10.1016/j.joule.2020.01.012
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发表时间：
2020-03-18
期刊：
影响因子：
39.8
通讯作者：
Yan, Yanfa
中科院分区：
文献类型：
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作者：
Awni, Rasha A.;Song, Zhaoning;Yan, Yanfa
基于电容的技术已用于测量卤化物钙钛矿太阳能电池（PSC）的电性能，例如缺陷活化能和密度、载流子浓度和介电常数，这为评估器件性能提供了关键信息。在这里，我们表明基于电容的技术不能用于可靠地分析钙钛矿层或其界面中的缺陷特性，因为高频电容特征是由空穴传输层（HTL）中电荷载流子的响应引起的。对于无HTL PSC，高频电容可以被视为分析钙钛矿层介电常数的几何电容，因为钙钛矿层中不存在电荷载流子的俘获和脱俘获。我们进一步发现低频电容特征可用于计算钙钛矿层离子电导率的活化能，但必须避免与电荷传输材料的重叠效应。
Capacitance-based techniques have been used to measure the electrical properties of halide perovskite solar cells (PSCs) such as defect activation energy and density, carrier concentration, and dielectric constant, which provide key information for evaluating the device performance. Here, we show that capacitance-based techniques cannot be used to reliably analyze the properties of defects in the perovskite layer or at its interface, because the high-frequency capacitance signature is due to the response of charge carriers in the hole-transport layer (HTL). For HTL-free PSCs, high-frequency capacitance can be considered as the geometric capacitance for analyzing the dielectric constant of the perovskite layer because there is no trapping and de-trapping of charge carriers in the perovskite layer. We further find that the low-frequency capacitance signature can be used to calculate the activation energy of the ionic conductivity of the perovskite layer, but the overlapping effects with charge transport materials must be avoided.