Unveiling the interaction between fragments of ABX3 halide perovskite and Ti3C2F2 MXene monolayer

Abstract

The combination of halide perovskites (ABX₃) and two-dimensional (2D) MXenes offers a compelling platform for the rational design of interfaces in next-generation perovskite-based photovoltaic technologies. In this work, we investigate the interaction between the fragments of halide perovskite (A, B, X, AX, BX₂) and the Ti₃C₂F₂ MXene surface using ab initio density functional theory calculations, where A = MA, FA, Cs; B = Pb; and X = Cl, Br, and I. Finite-temperature effects (up to 400 K) were incorporated through Gibbs free adsorption energies, including vibrational zero-point, enthalpic, and entropic contributions. The most favorable adsorbate configurations exhibit a clear hierarchy in binding strength with or without temperature corrections. For example, without temperature corrections, species A show the strongest chemisorption, with adsorption energies of approximately −2.00 eV, while halide X adsorbates exhibit intermediate binding strengths (−1.80 eV to −0.60 eV), which are systematically correlated with the electronegativity of the halogen. In contrast, the fragments B, AX, and BX₂ are only weakly bound, with adsorption energies in the range −0.80 eV to −0.50 eV. At room temperature, all fragments remain thermodynamically stable on the MXene surface except MACl and MABr, which are destabilized by large zero-point energy contributions. Adsorption induces significant structural distortions, with MXene bond elongations exceeding 13% near the adsorption sites and molecular deformations producing mean relative errors above 3.5% for selected neutral fragments. These structural changes lead to quantitative differences between adsorption and interaction energies. Electronic structure analysis shows that FA, Pb, and I introduce states at the Fermi level, while MAX, FAX, and CsX generate states progressively closer to the Fermi level following the halide sequence Cl < Br < I.