Benchmarking First-Principles Approaches for the Band Gap Prediction of Nanoporous Materials

Area of Science:

• Computational Materials Science
• Quantum Chemistry
• Nanoporous Materials

Background:

• Accurate prediction of electronic properties, such as band gaps, is crucial for designing functional nanoporous materials.
• Density Functional Theory (DFT) and its extensions are widely used but require careful benchmarking for specific material classes.

Purpose of the Study:

• To comprehensively benchmark first-principles calculation methods for fundamental and optical band gaps in nanoporous materials (MOFs, COFs, zeolites).
• To compare the performance of DFT with hybrid functionals, self-consistent extended Hubbard interactions, G0W0 approximation, and Bethe-Salpeter Equation (BSE).

Main Methods:

• Benchmarking of DFT, HSE06, self-consistent extended Hubbard interactions, G0W0 approximation, G0W0+BSE, and time-dependent DFT (TDDFT) with PBE functional.
• Calculation of fundamental and optical band gaps and absorption spectra for representative nanoporous materials.

Main Results:

• HSE06 underestimates fundamental band gaps compared to G0W0.
• G0W0+BSE provides accurate optical band gaps, outperforming TDDFT (PBE) with lower mean absolute errors (0.68 eV vs 1.00 eV).
• Exciton binding energies are larger in nanoporous materials due to localized VBM and CBM.

Conclusions:

• G0W0+BSE is a reliable method for predicting optical band gaps in nanoporous materials.
• The study offers guidance for selecting appropriate computational methods for high-porosity materials.
• Understanding exciton behavior is key for applications of these materials.