Eur. Phys. J. Appl. Phys. 99, 27 (2024)
https://doi.org/10.1051/epjap/2024240090

Original Article

Effect of TiO₂ structure on hysteretic behaviors in CH₃NH₃PbI₃ perovskite solar cells

Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon SK S7N 5E2, Canada

^* e-mail: ali.abd.ziabari@gmail.com
^** e-mail: gapsoo.chang@usask.ca

Received: 14 May 2024
Accepted: 4 September 2024
Published online: 16 October 2024

Abstract

This work explores a mechanism behind hysteresis in CH₃NH₃PbI₃ perovskite solar cells. The solar cells in this work employed either compact TiO₂, mesoporous TiO₂, or a combination of compact and mesoporous TiO₂ as an electron transport layer. The solar cells using compact TiO₂ layer displayed the most pronounced hysteresis compared to those which made use of mesoporous TiO₂. Different hysteretic behavior is attributed to difference in the built-in electric fields present in the architecture of perovskite solar cell. The solar cells with a compact TiO₂ layer have a built-in field which allows for iodide ions to migrate and accumulate near to the interface of indium-tin-oxide electrode, ultimately causing a reduction in the measured power conversion efficiency for forward bias scans. In case of the cells with a mesoporous TiO₂ layer, they have the built-in fields configured in such a way that iodide ions are blocked from migrating on a large scale to the vicinity of the ITO electrode. This results in the reduced hysteresis in perovskite solar cells when a mesoporous TiO₂ electron transport layer is employed.