Williamson Kyle I, Herr Daniel J C, Mo Yirong
Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina, USA.
J Comput Chem. 2024 Sep 30;45(25):2119-2127. doi: 10.1002/jcc.27432. Epub 2024 May 17.
Bandgap is a key property that determines electrical and optical properties in materials. Modulating the bandgap thus is critical in developing novel materials particularly semiconductors with improved features. This study examines the bandgap, highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) energy level trends in a metal organic framework, metal-organic framework 5 (MOF-5), as a function of Hammett substituent effect (with the constant σ in the meta-position of the benzene ring) and solvent dielectric effect (with the constant ε). Specifically, experimental design and response surface methodologies helped to assess the significance of trends and correlations between these molecular properties with σ and ε. While the HOMO and LUMO decrease with increasing σ, the LUMO exhibits greater sensitivity to the substituent's electron withdrawing capability. The relative difference in these trends helps to explain why the bandgap tends to decrease with increasing σ.
带隙是决定材料电学和光学性质的关键特性。因此，调节带隙对于开发具有改进特性的新型材料，特别是半导体材料至关重要。本研究考察了金属有机框架材料金属有机框架5（MOF-5）的带隙、最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）能级趋势，这些趋势是哈米特取代基效应（苯环间位具有常数σ）和溶剂介电效应（具有常数ε）的函数。具体而言，实验设计和响应面方法有助于评估这些分子性质与σ和ε之间趋势及相关性的显著性。虽然HOMO和LUMO随着σ的增加而降低，但LUMO对取代基的吸电子能力表现出更高的敏感性。这些趋势的相对差异有助于解释为什么带隙往往会随着σ的增加而减小。
