Enhanced solar harvesting efficiency in nanostructured MXene monolayers based on scandium and yttrium

MXenes have garnered significant attention in nanoelectronics due to their tunable electronic properties. Such tunability makes them potential candidates for high-efficiency solar energy applications. Here, we investigate the structural, electronic, optical, and excitonic properties of 2D M$_2$CT$_2$ (M = Y, Sc; T = O, F, S, Cl, Se, Br, Te, I, H, OH) MXene monolayers using a computational protocol that combines first-principles and semi-empirical methods. By employing an automated workflow that integrates five distinct Workflow Active Nodes (WaNos) within the SimStack framework, we systematically assessed the structural stability and electronic properties of 22 candidate monolayers. This approach enhances computational efficiency and ensures reproducibility by adhering to FAIR and TRUE data principles. Phonon dispersion analysis revealed that ten systems are stable, five are metastable, and seven are unstable. Among the stable and metastable monolayers, we identified several semiconductors—Y$_2$CCl$_2$, Y$_2$CBr$_2$, Y$_2$CH$_2$, Y$_2$CI$_2$, Sc$_2$CCl$_2$, Sc$_2$CBr$_2$, Sc$_2$CF$_2$, and Sc$_2$CH$_2$—with indirect Heyd–Scuseria–Ernzerhof (HSE06) band gaps ranging from 1.24–1.90 eV. ... mehrExcitonic effects induced by quantum confinement contribute to exciton binding energies from 210–470 meV, consistent with typical 2D materials. Additionally, some monolayers demonstrate potential for solar harvesting applications, with predicted energy conversion efficiency approaching 30% under full photon absorption.