TITLE:
Performance Enhancement of Lead-Free K2TiI6-Based Perovskite Solar Cells Using SCAPS-1D Simulation Study
AUTHORS:
Rony Tota, Tarikul Islam Tasin, Shak Mahmudul Hasan, Md. Morsalin, Zamil Sultan, Muien Ahmed Arnob, Mehedi Hasan Tanim, Najiba Abedin Sajan
KEYWORDS:
Lead-Free PSCs, K2TiI6, SCAPS-1D Simulation, ETL, HTL, Power Conversion Efficiency (PCE), Device Optimisation, Interface Defects, Quantum Efficiency (QE)
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.13 No.10,
October
28,
2025
ABSTRACT: Perovskite solar cells (PSCs) have emerged as one of the most promising candidates for future renewable energy solutions due to their low cost, ease of fabrication, and potential for high efficiency. The lead-free perovskite element in this study demonstrates a high absorption coefficient and an optimal optical band, making it a suitable candidate for sustainable photovoltaic technologies. The goal of the experiment was to optimise the device’s defect density, acceptor density (NA), donor density (ND), and absorber thickness. Fluorine-doped tin-oxide (FTO) was used as the window layer, D-PBTTT-14 as the hole transport layer (HTL), Au as the back layer, K2TiI6 as the absorber layer, and CdZnS as the electron transport layer (ETL) to improve device performance. This study employs a PSC based on K2TiI6 and SCAPS-1D simulation to evaluate its structural, photovoltaic, and optical properties. In particular, the effects of carrier concentration, absorber thickness, and defect densities were thoroughly studied and analysed via simulation. Significant improvements in open-circuit voltage (Voc), FF, and efficiency were observed with the implementation of this solar cell (SC). The study also investigates the impact of operating temperature on efficiency and other electrical properties. Optimisation of the material thicknesses was performed to achieve the desired target. The optimised cell structure, FTO/CdZnS/K2TiI6/D-PBTTT-14/Au, achieved a FF of 86.50%, an Voc of 1.33 V, a short circuit current density (Jsc) of 24.42 mA/cm2, and a high performance efficiency of 28.11%. Factors such as operating temperature, electron affinity, surface recombination velocity, series resistance, shunt resistance, and buffer/absorber and absorber/HTL interference were carefully optimised to enhance performance. In conclusion, lead-free PSCs based on K2TiI6 present a highly promising option for sustainable energy solutions, contributing to the development of cost-effective and high-efficiency photovoltaic technologies.