Light-harvesting efficiency and excitonic properties of a two-dimensional Zr2CO2/SiS2 heterobilayer

Huacarpuma B.D.A.; Pereira T.A.S.; Milošević M.V.; Silva A.M.A.; Dias A.C.; Junior L.A.R. · Surfaces and Interfaces (2026) · DOI: 10.1016/j.surfin.2026.110557

Resumen

Their exceptional electronic properties often promote two-dimensional (2D) heterostructures for solar cell applications. However, systematic investigations into the influence of excitonic effects on their optical response and power conversion efficiency (PCE) remain scarce. Here, we present a comprehensive first-principles study of the structural, thermodynamic, electronic, optical, and excitonic properties of the 2D Zr2CO2/SiS2 heterobilayer. Our electronic structure analysis shows that the system is an indirect semiconductor, exhibiting band gaps of 0.35 eV at the PBE level and 1.13 eV at the HSE06 range-hybrid functional. To clarify its optical and excitonic behavior, we employ a tight-binding model combined with the Bethe–Salpeter equation (BSE), and analyze the response using both the independent-particle approximation and the BSE formalism. Quantum-confinement-induced excitonic effects yield a high binding energy of 171 meV, comparable with 2D transition-metal dichalcogenides. Finally, the PCE of Zr2CO2/SiS2 heterobilayer is evaluated using both the spectroscopy-limited maximum efficiency limit and the Shockley–Queisser framework. The calculated PCE ranges between 16.58 % and 26.44 %, underscoring the potential of this heterostructure for photovoltaic applications.

Instituciones: Universidad Nacional de San Agustín de Arequipa