Minbashi Mehran, Yazdani Elnaz
Department of Physics, Tarbiat Modares University, P. O. Box 14115-175, Tehran, Iran.
Phys Chem Chem Phys. 2023 Feb 8;25(6):5146-5155. doi: 10.1039/d2cp04714d.
The ionic-electronic drift-diffusion model is employed to simulate the hysteresis behavior in perovskite solar cells (PSCs) under low-to-moderate conditions; the migrating ions stop at the HTL/ETL interfaces. However, for high-applied bias voltage, illumination, air exposure for weeks, and special cell configuration, these ions can also reach the external contact interfaces, presenting anomalous hysteresis behavior. This has already been confirmed experimentally but has not been modeled yet. The ion flux toward contacts has been considered in our model by introducing new parameters, such as boundary absorption velocity for anions and cations (). The results comprise low hysteresis in the - characteristic by an increase in the boundary absorption velocity. Moreover, by increasing the scanning time (low scan rate), ions have enough time to reach the ETL/contact and HTL/contact interfaces, which leads to enhanced and inverted hysteresis and decreased efficiency. Finally, a unique and optimized set of material parameters, mainly related to ion migration parameters, has been achieved. Therefore, the cell efficiency is enhanced from 16.47 to 26.38% by using the optimized parameters. Our results show that ion migration prevention has an essential role in producing highly efficient, hysteresis-free, and stable solar cells that are ready for real-world applications.
采用离子-电子漂移-扩散模型来模拟中低条件下钙钛矿太阳能电池（PSC）中的滞后行为；迁移离子会在HTL/ETL界面处停止。然而，对于高施加偏置电压、光照、数周的空气暴露以及特殊的电池结构，这些离子也能到达外部接触界面，呈现出异常的滞后行为。这一点已通过实验得到证实，但尚未建立模型。在我们的模型中，通过引入新参数，如阴离子和阳离子的边界吸收速度（），考虑了朝向接触的离子通量。结果包括通过增加边界吸收速度，-特性中的滞后减小。此外，通过增加扫描时间（低扫描速率），离子有足够的时间到达ETL/接触和HTL/接触界面，这导致滞后增强和反转以及效率降低。最后，获得了一组独特且优化的材料参数，主要与离子迁移参数相关。因此，通过使用优化参数，电池效率从16.47%提高到了26.38%。我们的结果表明，防止离子迁移对于生产适用于实际应用的高效、无滞后且稳定的太阳能电池具有至关重要的作用。
