Experimental Validation of Optimized Solar Cell Capacitance Simulation for Rheology-Modulated Carbon-Based Hole Transport Layer-Free Perovskite Solar Cell

The hole transport layer (HTL)-free carbon-based perovskite solar cell (C-PSC) has attracted the attention of researchers due to its ease of fabrication and reduced costs in the manufacturing process. The rheological and physical characteristics of the solutions influence the layer quality of different device fabrication methods. Herein, the HTL-free structure of C-PSC through solar cell capacitance simulator (SCAPS) simulations is analyzed and validated with experimental results using rheology-varied mesoporous-TiO₂ (m-TiO₂) paste. Regarding the m-TiO₂ rheology, two different samples (Type 1 and Type 2) are used, and six different configurations by thickness variation are analyzed utilizing SCAPS simulations. For Type 1 and Type 2, the best configurations exhibit theoretical efficiencies of 16.40% and 16.81%, respectively, without the influence of the resistance factor. After replicating similar designs in experiments, the efficiencies become 10.12% and 12.20%, respectively. Further, results are investigated by SCAPS simulations incorporating series and shunt resistance values, resulting in efficiencies of 10.56% and 12.59% for Type 1 and Type 2, respectively, which is comparable with actual devices. Finally, the variation of theoretical and experimental results is scrutinized with the help of impedance spectroscopy and external quantum efficiency, demonstrating the significance of this work for commercialization aspects.