Improving the performance of perovskite solar cells with carbon nanotubes as a hole transport layer

There are several types of organometallic halide perovskite solar cells (OHPSCs), but the carbon-based PSC has the lowest materials/fabrication cost and the longest-term stability, making it the most promising for practical application. In this study, we used multi—walled carbon nanotubes (MWCNTs) as the hole transport layer in the PSC architecture. We experimentally achieved an optimized efficiency of 13.7% for a MWCNTs-based device. Besides, this research describes a simulation-guided optimization process to fabricate high-performance MWCNT-based photovoltaics. We have thoroughly investigated the effect of different parameters, such as the total defect density of the absorber, the thickness of the MWCNTs film, the thickness of the absorber, shunt resistance, series resistance, and temperature, utilizing numerical simulations. By using the thin film photovoltaic program SCAPS-1D, we were able to simulate defect states and interfaces between layers to get as close as possible to a realistic PSC in our simulations and analysis. An optimized PSC of F-doped tin oxide (FTO)/titanium dioxide (TiO₂)/MAPbI₃/MWCNTs/gold (Au) is designed here with a voltage-open circuit (V_OC) of 1.100 V, a short-current density (J_SC) of 19.192 mA/cm², and efficiency of 18.3% with a high fill factor (FF) of 86.62%, which is among the best for carbon-based OHPSCs.