Dielectric Relaxation Processes, Electronic Structure, and Band Gap Engineering of MFU‐4‐type Metal‐Organic Frameworks: Towards a Rational Design of Semiconducting Microporous Materials
Dielectric Relaxation Processes, Electronic Structure, and Band Gap Engineering of MFU‐4‐type Metal‐Organic Frameworks: Towards a Rational Design of Semiconducting Microporous Materials
复制标题
DOI：
10.1002/adfm.201400083
复制
发表时间：
2014-07
影响因子：
19
通讯作者：
P. Sippel;D. Denysenko;A. Loidl;P. Lunkenheimer;Germán Sastre;D. Volkmer
中科院分区：
文献类型：
--
作者：
P. Sippel;D. Denysenko;A. Loidl;P. Lunkenheimer;Germán Sastre;D. Volkmer
MFU - 4型金属有机骨架的电子结构和带隙可以被系统地改造，从而形成一类等结构微孔固体。微晶样品的电学性质通过温度相关的宽带介电光谱和光学光谱进行了研究，并在密度泛函理论的多个层次上对框架和簇模型化合物进行了全带结构计算。综合结果收集了从零维团簇到三维周期固体时分子轨道相对位移和分散的详细图像，从而允许通过通用构建块方法制定定制这类半导体微孔固体电子特性的指导方针。因此，MFU‐4型化合物的带隙工程可以通过调整有机配体的共轭度或选择适当的金属来实现，其部分占据d -轨道产生低于配体LUMO能量的带，例如，在Co‐MFU‐4中由八面体Co（II）离子完成。
The electronic structures and band gaps of MFU‐4‐type metal‐organic frameworks can be systematically engineered leading to a family of isostructural microporous solids. Electrical properties of the microcrystalline samples are investigated by temperature‐dependent broad‐band dielectric and optical spectroscopy, which are corroborated by full band structure calculations performed for framework and cluster model compounds at multiple levels of density functional theory. The combined results glean a detailed picture of relative shifts and dispersion of molecular orbitals when going from zero‐dimensional clusters to three‐dimensional periodic solids, thus allowing to develop guidelines for tailoring the electronic properties of this class of semiconducting microporous solids via a versatile building block approach. Thus, engineering of the band gap in MFU‐4 type compounds can be achieved by adjusting the degree of conjugation of the organic ligand or by choosing an appropriate metal whose partially occupied d‐orbitals generate bands below the LUMO energy of the ligand which, for example, is accomplished by octahedral Co(II) ions in Co‐MFU‐4.