Citation

Faysal, A. A. and Ghosh, Swarup and Lee, It Ee and Wali, Qamar and Aamir, Muhammad and Ali, M. A. M. and Hossain, M. M. and Jahan, N. and Hossain, M. Z. and Akhtaruzzaman, Md. and Uddin, M. M. (2026) First-principles study of Y2CCl2 and Janus Y2CClX (X = F, Br, I) MXenes for photovoltaic applications. Scientific Reports, 16 (1). ISSN 2045-2322

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Abstract

Two-dimensional (2D) Janus MXenes offer a promising platform for photovoltaic (PV) absorbers, as asymmetric surface terminations can simultaneously tailor band gaps, optical response, and builtin electric field, which promote charge carrier separation. Here, a systematic first-principles study of the symmetric halide-terminated MXene Y2CCl2 and the Janus compounds Y2CClX (X=F, Br, I) using density functional theory has been performed. Hybrid-functional (HSE06) electronic structure calculations identify all compounds as indirect-gap semiconductors with gaps of 1.63 eV (Y2CCl2), 1.36 eV (Y2CClF), 1.57 eV (Y2CClBr), and 1.21 eV (Y2CClI). Orbital-resolved density of states, chargepartitioning, and electron-localization function analyses reveal charge transfer from Y toward C and the surface halogens, with Janus functionalization producing pronounced surface asymmetry. Janus functionalization further produces substantial surface asymmetry in the work function, yielding work function differences of 3.09, 1.63, and 2.10 eV for Y2CClF, Y2CClBr, and Y2CClI, respectively, suggesting intrinsic fields that may assist carrier separation. Optical calculations show strong absorption in the visible window with coefficients on the order of 105 cm−1. Carrier-transport descriptors reveal smaller electron than hole effective masses across the series, and the screened 2D Mott–Wannier model yields exciton binding energies of 1.09, 1.12, 1.02, and 0.91 eV for Y2CCl2, Y2CClF, Y2CClBr, and Y2CClI, respectively. Finally, PV metrics computed within the modified Shockley–Queisser formalism predict maximum efficiencies of 23.10%, 25.66%, 23.92%, and 23.01% for Y2CCl2, Y2CClF, Y2CClBr, and Y2CClI, respectively, with Y2CClF emerging as the most favorable absorber due to its near-optimal gap and highest maximum power density. Overall, this study demonstrates that halogen-functionalized Y2Cbased Janus MXenes are fascinating materials for next-generation photovoltaic and optoelectronic devices.

Item Type:	Article
Uncontrolled Keywords:	Electric field, optical absorption
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK301-399 Electric meters
Divisions:	Faculty of Artificial Intelligence & Engineering (FAIE)
Depositing User:	Ms Rosnani Abd Wahab
Date Deposited:	02 Oct 2026 06:23
Last Modified:	02 Oct 2026 06:23
URII:	http://shdl.mmu.edu.my/id/eprint/16837

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