Engineering of Band Gap in Metal鈥揙rganic Frameworks by Functionalizing Organic Linker: A Systematic Density Functional Theory Investigation

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• 作者：Hung Q. Pham ; Toan Mai ; Nguyen-Nguyen Pham-Tran ; Yoshiyuki Kawazoe ; Hiroshi Mizuseki ; Duc Nguyen-Manh
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：March 6, 2014
• 年：2014
• 卷：118
• 期：9
• 页码：4567-4577
• 全文大小：520K
• 年卷期：v.118,no.9(March 6, 2014)
• ISSN：1932-7455

文摘

A systematic investigation on electronic band structure of a series of isoreticular metal鈥搊rganic frameworks (IRMOFs) using density functional theory has been carried out. Our results show that halogen atoms can be used as functional groups to tune not only the band gap but also the valence band maximum (VBM) in MOFs. Among halogen atoms (F, Cl, Br, I), iodine is the best candidate to reduce the band gap and increase the VBM value. In addition, it has been found that for the antiaromatic linker DHPDC (1,4-dihydropentalene-2,5-dicarboxylic acid) the energy gap is 0.95 eV, which is even lower than those calculated for other aromatic linkers, i.e., FFDC (furo[3,2-b]furan-2,5-dicarboxylic acid) and TTDC (thieno[3,2-b]thiophene-2,5-dicarboxylic acid). By analyzing the lowest unoccupied molecular orbital鈥揾ighest occupied molecular orbital gaps calculated at the molecular level, we have highlighted the important role of the corresponding organic linkers in the MOF band gap. In particular, the change of C鈥揅鈥揅鈺怬 dihedral angle in the organic linker can be used to analyze the difference of band gaps in MOF crystals. It is shown that a deep understanding of chemical bonding within linker molecules from electronic structure calculations plays a crucial role in designing semiconductor properties of MOF materials for engineering applications.