First principles exploration of structural, electronic, and optical properties of M2XT2 (M = Hf, Zr; X = C; T = O, F) MXenes for photovoltaic applications

Abstract

MXene compounds are promising candidates for energy-related applications because of their tunable electronic and surface properties. In this work, we explore structural, electronic, and optical features of M₂XT₂ (M = Hf, Zr; X = C; T = O, F) using density functional theory (DFT) within the WIEN2k computational framework. These compounds show non-magnetic behavior and exhibit a hexagonal geometry (space group# 194). Phonon dispersion analysis confirms that these compounds are dynamically stable. Hf₂CO₂ and Zr₂CO₂ exhibited indirect bandgaps of 1.1 and 1.12 eV, respectively, classifying them as solar absorber materials. Conversely, Hf₂CF₂ and Zr₂CF₂ are semimetals because of the small energy interband overlapping. Their optical properties were explained in terms of optical conductivity, loss parameter, extinction coefficient, refractive index, reflectivity, absorption coefficient, and dielectric function. Our findings indicate that M₂XT₂ materials are suitable for sustainable energy technologies, including photovoltaic cells and other optoelectronic applications.