Beyond the First Quadrant: Origin of the High Frequency Intensity-Modulated Photocurrent/Photovoltage Spectroscopy Response of Perovskite Solar Cells
Beyond the First Quadrant: Origin of the High Frequency Intensity-Modulated Photocurrent/Photovoltage Spectroscopy Response of Perovskite Solar Cells
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DOI：
10.1002/solr.202100159
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发表时间：
2021-04-09
期刊：
影响因子：
7.9
通讯作者：
Carnie, Matthew J.
中科院分区：
文献类型：
--
作者：
Pockett, Adam;Spence, Michael;Carnie, Matthew J.
钙钛矿太阳能电池的小扰动频域测量的完整解释已被证明是具有挑战性的。在强度调制光电流/光电压光谱（IMPS/IMVS）测量中尤其如此，其中高频响应被仪器限制所掩盖。本文展示了一种新的实验方法，能够准确地解析钙钛矿器件的高频响应-通常在复杂平面的第二和第三象限观察到。通过结合单频IMPS/IMVS测量，可以构建这些器件在初始照明响应期间的IMPS/IMVS响应的时间依赖性。这揭示了当器件达到稳态时，高频下显著的负光电流/光电压信号，这与可比较的时域瞬态测量结果相一致。这些技术可以评估潜在的界面重组和离子迁移过程，而使用稳态测量并不总是很明显。研究和缓解这些过程的能力对于优化设备的实际操作至关重要。
The complete interpretation of small perturbation frequency-domain measurements on perovskite solar cells has proven to be challenging. This is particularly true in the case of intensity-modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) measurements in which the high frequency response is obscured by instrument limitations. Herein, a new experimental methodology capable of accurately resolving the high frequency response-often observable in the second and third quadrants of the complex plane-of a range of perovskite devices is demonstrated. By combining single-frequency IMPS/IMVS measurements, it is able to construct the time dependence of the IMPS/IMVS response of these devices during their initial response to illumination. This reveals significant negative photocurrent/photovoltage signals at high frequency while devices reach steady state, which is in keeping with observations made from comparable time-domain transient measurements. These techniques allow the underlying interfacial recombination and ion migration processes to be assessed, which are not always evident using steady-state measurements. The ability to study and mitigate these processes is vital in optimizing the real-world operation of devices.