Proceedings of Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP20)
DOI: https://doi.org/10.29363/nanoge.iperop.2020.055
Publication date: 14th October 2019
In this paper, we developed a simulation tool to analyze the hysteresis effect of JV curve in Perovskite solar cells. Some studies have shown that the ion migration is the main reason leading to the hysteresis effect of JV curve [1-3]. However, the typical commercial simulation software can only demonstrate the fixed ion distribution [4],which can only model the effect of ion accumulation at two sides. However, it's hard to explain as the dynamic changes of ion migration under different bias scan rates. Hence, we developed a 2D simulation program that can handle the time dependent ion migration movement. This program also model the light absorption with texture surface as well as the carrier transport in the devices. In this program, the optical field was solved by FD-TD method and electrical properties were solved by Poisson & drift-diffusion solver, the detail can be referred to Ref. [5]. The time-dependent drift-diffusion model especially for ion migration was added into this program and couple with the Poisson and drift-diffusion solver for carriers. Hence, we can consider the electrical field variation with ion migration in our modeling. Partial simulation results were shown in this abstract due to limit space.. The structure was formed by Au (80nm) / PCBM (20nm) / MAPbI3 (300nm) / PEDOT:PSS (20nm) / ITO (150nm) [6]. Fig. (a) is the ion accumulation with different pre-bias for 10 seconds. In the Fig. (b), the solid line is simulation result of conduction band without ion migration effect and the dash line is the conduction band that considered the ion accumulation. These figures show that the ion accumulation was mainly decided by pre-bias condition (the electrical field at this bias). To understand the effect of ion distribution in electrical properties, the different voltage-bias scan rate is was performed to understand the degree of ion migration. Fig. (c) shows the hysteresis effect under different scan rate. The trend of simulation results was close to the experiment data [1]. And some studies have shown that the ion migration would lead to the defect generation in Perovskite [1]. Fig. (d) shows the result with consideration of defect generation after ion migration, we can observe that the open-circuit voltage would be strongly affected by different defect state density and ion accumulation. By consideration the defects, the trend of simulation result is more close to the experiment result [1].
Authors would like to thanks the support by Ministry of Science and Technology, Taiwan (MOST) under grant No. MOST 106- 2221-E-002-164-MY3 and MOST 108-2628-E-002-010-MY3.