Enhancing Stability and Efficiency in Perovskite Solar Cells: Insights into Inorganic HTL Deposition and Interface Defect Passivation

Abstract

The perovskite solar cell (PSC) as an emerging and promising type of solar cell have been extensively studied, but instability is still a major challenge. Replacing the hygroscopic organic hole transport layer (HTL) in PSC can result in the improvement of the device stability. However, it is still difficult to deposit inorganic HTL unto underlying perovskite layer without eroding or distorting it, in the regular n-i-p architecture thereby inducing defects at the interface and reducing the performance of the device. In this study, performance of PSCs with inorganic HTL is modelled using SCAPS-1D. The perovskite-HTL interface defect density was varied from 1.0 × 1012 to 1.0 × 1020 cm−3. We realized that, for PSCs based on some hole transport materials (HTMs), the effect of interface defect density was not significant. We observed that the HTL/perovskite valence band offset (VBO) play a significant role in the phenomenon observed. Particularly, zero or slightly positive VBO results in the increase in both defect tolerance and device efficiency. This information provides insights into the fabrication of PSCs with improved interface defect passivation and also enable the fabrication of perovskite solar cell based on physically deposited inorganic charge transport materials.