Communication Dans Un Congrès Année : 2025

DFTB Parametrization for Iodide and Bromide Perovskites and Heterostructures

Résumé

Halide perovskites exhibit remarkable optoelectronic properties, making them promising candidates in energy-related and optoelectronic applications. However, the reduction in crystal dimension from 3D to low-dimensional perovskite structures introduces significant quantum and dielectric confinement effects, resulting in larger band gaps and exciton-binding energies. Moreover, these low-dimensional configurations naturally involve larger unit cells, posing computational challenges for standard density functional theory (DFT) calculations. Additionally, the well-known tendency of DFT to underestimate band gaps complicates the study of such systems, particularly when accurate band gap predictions are crucial. To overcome these limitations, we employ density functional tight-binding (DFTB), a semi-empirical approach based on DFT that enables the efficient simulation of larger systems at lower computational costs.1-3 Crucially, we developed and refined DFTB parameters tailored not only for 3D perovskites (e.g., CsPbI3, MAPbI3, CsPbBr3, MAPbBr3), but also for a range of 2D halide perovskites (e.g., Cs2PbI4, BA2PbI4, and BA2PbBr4), including both iodide- and bromide-based materials and its alloys. Our parameter sets are suitable for structure relaxations and accurate electronic property evaluations, ensuring high accuracy in band gap predictions and electronic structure analysis. By applying our approach to model 2D perovskites, we demonstrate excellent agreement with experimental data concerning lattice parameters, electronic band gaps, and reduced effective masses. In particular, the new DFTB parameters for bromide perovskites exhibit accurate predictive capabilities. These findings represent a promising foundation for extending DFTB to other low-dimensional (1D, 0D, hollow) perovskite nanostructures, and even more complex perovskite-based systems, including 2D/3D perovskite heterostructures, and halide mixed perovskites, that have recently shown enhanced operational stability and/or optoelectronic properties in photovoltaic applications. Our parametrization framework thus provides a robust and computationally efficient pathway for exploring the vast design space of low-dimensional perovskites in future device engineering and research.

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Dates et versions

hal-05219391 , version 1 (22-08-2025)

Identifiants

  • HAL Id : hal-05219391 , version 1

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Junke Jiang, Tammo van der Heide, Simon Thébaud, Carlos Raúl Lien-Medrano, Arnaud Fihey, et al.. DFTB Parametrization for Iodide and Bromide Perovskites and Heterostructures. EMRS Spring 2025, May 2025, Strasbourg, France. ⟨hal-05219391⟩
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