Tunneling Electrical Connection to the Interior of Metal鈥揙rganic Frameworks
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- 作者：Shuangbing Han ; Scott C. Warren ; Seok Min Yoon ; Christos D. Malliakas ; Xianliang Hou ; Yanhu Wei ; Mercouri G. Kanatzidis ; Bartosz A. Grzybowski
- 刊名：Journal of the American Chemical Society
- 出版年：2015
- 出版时间：July 1, 2015
- 年：2015
- 卷：137
- 期：25
- 页码：8169-8175
- 全文大小：527K
- ISSN：1520-5126
文摘
Metal鈥搊rganic frameworks (MOFs) are typically poor electrical conductors, which limits their uses in sensors, fuel cells, batteries, and other applications that require electrically conductive, high surface area materials. Although metal nanoclusters (NCs) are often added to MOFs, the electrical properties of these hybrid materials have not yet been explored. Here, we show that adding NCs to a MOF not only imparts moderate electrical conductivity to an otherwise insulating material but also renders it photoconductive, with conductivity increasing by up to 4 orders of magnitude upon light irradiation. Because charge transport occurs via tunneling between spatially separated NCs that occupy a small percent of the MOF鈥檚 volume, the pores remain largely open and accessible. While these phenomena are more pronounced in single-MOF crystals (here, Rb-CD-MOFs), they are also observed in films of smaller MOF crystallites (MIL-53). Additionally, we show that in the photoconductive MOFs, the effective diffusion coefficients of electrons can match the typical values of small molecules diffusing through MOFs; this property can open new vistas for the development of MOF electrodes and, in a wider context, of electroactive and light-harvesting MOFs.