Room Temperature Metallic Conductivity in a Metal-Organic Framework Induced by Oxidation
Room Temperature Metallic Conductivity in a Metal-Organic Framework Induced by Oxidation
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DOI：
10.1021/jacs.9b06898
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发表时间：
2019-10-16
影响因子：
15
通讯作者：
Marinescu, Smaranda C.
中科院分区：
文献类型：
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作者：
Clough, Andrew J.;Orchanian, Nicholas M.;Marinescu, Smaranda C.
含有氧化还原活性连接体的金属有机框架（MOF）导致杂化化合物表现出高导电性，这使得它们能够在电子和电催化应用中使用。虽然许多计算研究预测二维 (2D) MOF 是金属的，但大多数实验表明冷却时电导率下降，表明电子能带结构中存在间隙。迄今为止，据报道，只有少数 MOF 在冷却后表现出较高的电导率，表明其具有金属特性，这凸显了更好地了解电导率起源的必要性。最近报道称，含有铁双（二硫醇）基序的二维 MOF 表现出具有记录载流子迁移率的半导体行为。在此，我们报告说，高结晶度和客体物质的消除导致铁2,3,6,7,10,11-三苯撑六硫醇（THT）MOF，FeTHT，在冷却时表现出从半导体到金属的复杂转变，类似于类似的CoTHT所显示的情况。值得注意的是，将 FeTHT 暴露在空气中会显着影响半导体到金属的转变温度（100 至 300 K），并最终导致材料在室温及以上温度下表现出类金属特性。这项研究表明这些材料可以耐受大量的掺杂，最终导致电荷离域和类金属导电性，这是使其在化学电阻传感和光电子学中使用的重要一步。
Metal-organic frameworks (MOFs) containing redox active linkers have led to hybrid compounds exhibiting high electrical conductivity, which enables their use in applications in electronics and electrocatalysis. While many computational studies predict two-dimensional (2D) MOFs to be metallic, the majority of experiments show decreasing conductivity on cooling, indicative of a gap in the electronic band structure. To date, only a handful of MOFs have been reported that exhibit increased electrical conductivity upon cooling indicative of a metallic character, which highlights the need for a better understanding of the origin of the conductivity. A 2D MOF containing iron bis(dithiolene) motifs was recently reported to exhibit semiconducting behavior with record carrier mobility. Herein, we report that high crystallinity and the elimination of guest species results in an iron 2,3,6,7,10,11-tripheylene-hexathiolate (THT) MOF, FeTHT, exhibiting a complex transition from semiconducting to metallic upon cooling, similar to what was shown for the analogous CoTHT. Remarkably, exposing the FeTHT to air significantly influences the semiconducting-to-metallic transition temperature (100 to 300 K) and ultimately results in a material showing metallic-like character at, and above, room temperature. This study indicates these materials can tolerate a substantial degree of doping that ultimately results in charge delocalization and metallic-like conductivity, an important step toward enabling their use in chemiresistive sensing and optoelectronics.