Identifying Practical DFT Functionals for Predicting 0D and 1D Organic Metal-Halide Hybrids

Low-dimensional organic metal-halide hybrids (LD-OMHHs) are a promising class of materials for applications in optical, magnetic, and quantum information technologies. Computational understanding of these materials necessitates reliable and efficient methods for property prediction, such as predicting the electronic band gap. This work systematically benchmarks three density functional theory (DFT) functionals as well as the impact of spin–orbital coupling on the band gap predictions for 110 experimentally reported LD-OMHHs. Surprisingly, the band gap predicted by the generalized gradient approximation (GGA) aligns similarly or better with experimentally measured values compared to two meta-GGA methods. Furthermore, spin–orbital coupling shows a limited impact on these predictions. The potential existence of significant excitonic effects might explain the discrepancies between meta-GGA and experimental band gaps. Our research also reveals that the direct use of the GGA functional can already be practical and efficient for high-throughput screening of LD-OMHHs with reasonable band gaps.