Band Gap Engineering of Paradigm MOF-5

Abstract

Recently, metal−organic frameworks (MOFs) have demonstrated great potential in photocatalysis and luminosity applications. However, most MOFs are dielectrics with substantial band gaps which limits applications of MOFs in the visiblelight region. In this paper, we systematically tune the band gap of paradigm MOF-5 by substituting new atoms for the corner elements (X 4 Y), in computer simulations using density functional theory. The new proposed materials are labeled X 4 Y−MOF-5 (X = Zn, Cd, Be, Mg, Ca, Sr, Ba; Y = O, S, Se, Te). These new materials have band gaps ranging from 1.7 to 3.6 eV. The underlying mechanism of tunability of band gap can be ascribed to the electronic states of chalcogen atoms (O, S, Se, Te) in the X 4 Y nodes and carbon atoms in the BDC linkers. The substantial tunability of band gap leads to a large absorption range covering the visible spectrum. These proposed new materials may be useful for future applications in visible-light promoted photocatalysis or luminosity. The tunability of other properties such as bulk modulus, chemical bonding, and optical properties were also investigated. These novel materials may also be useful for devices in nanoelectronics or optoelectronics.

A dual-functional UiO-66/TiO2 composite for water treatment and CO2 capture

“…Metal-organic frameworks (MOFs) are crystalline porous materials, which are well-known for their various applications, especially in the eld of heterogeneous catalysis and separation and storage of gases even in the photocatalytic eld. [9][10][11][12] Actually, MOFs with photocatalytic abilities have already been reported for a long time; MIL-125, for example, was rst synthesized by Dan-Hardi and was found to be photoactive. 13 Recently, Vinogradov prepared the depleted heterojunction MIL-125/TiO 2 , which was used in solar cells and showed excellent photocatalytic properties.…”

The effect of cluster size on the optical band gap energy of Zn-based metal–organic frameworks

“…This well isolated structural arrangement results in molecular-like electronic structures and leads to bands with minimal dispersion. [16][17][18][19][20][21][22][23][24] As MOFs are composed of metal or metal oxygen nodes and organic linkers, the electronic structure of a MOF can be influenced by interactions between metal or metal oxygen nodes and ligands. This offers the possibility of chemically tuning the electronic properties of the MOF by exchanging the linkers and/or metal or metal oxygen nodes.…”

Computational exploration of metal–organic frameworks: examples of advances in crystal structure predictions and electronic structure tuning

“…X 4 Y-MOF-5 where X ¼ Zn, Cd, Be, Mg, Ca, Sr, Ba and Y ¼ O, S, Se, Te), the virtual materials possessing optical band gaps ranging from 1.7 to 3.6 eV assigned to the electronic state of the chalcogen atoms. [82] It is worth commenting here that MOFs were referred early on, rather incorrectly, to as semiconductors, implying similarities with their inorganic counterparts.…”