Saha Sauvik, Ananthram K S, Hassan Nahid, Ugale Ajay, Tarafder Kartick, Ballav Nirmalya
Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India.
Department of Physics, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025, India.
Nano Lett. 2023 Oct 25;23(20):9326-9332. doi: 10.1021/acs.nanolett.3c02522. Epub 2023 Oct 16.
Two-dimensional (2D) metal-organic frameworks (MOFs) are usually associated with higher electrical conductivity and charge carrier mobility when compared with 3D MOFs. However, attaining metallic conduction in such systems through synthetic or postsynthetic modifications is extremely challenging. Herein, we present the fabrication of thin films of a 2D MOF, Cu(HHTP) (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), decorated with silver nanoparticles (AgNPs) exhibiting significant conductivity enhancement at room temperature. Variable-temperature electrical transport measurements across the low-temperature (200 K) to high-temperature (373 K) regime evidenced metallic conduction. Interestingly, thin films of a 3D MOF, CuTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane), upon decoration with AgNPs, disclosed a converse trend. The origin of such distinctive observations on AgNPs@Cu(HHTP) and AgNPs@CuTCNQ systems was comprehended by using first-principles density functional theory (DFT) calculations and attributed to an interfacial electronic effect. Our work sheds new light on rationally designing synthetic modifications in thin films of MOFs to tune the electrical transport property.
与三维金属有机框架（MOFs）相比，二维（2D）金属有机框架通常具有更高的电导率和电荷载流子迁移率。然而，通过合成或后合成修饰在这类体系中实现金属导电极具挑战性。在此，我们展示了一种二维MOF，即Cu(HHTP)（HHTP = 2,3,6,7,10,11 - 六羟基三亚苯）薄膜的制备，该薄膜装饰有银纳米颗粒（AgNPs），在室温下表现出显著的电导率增强。在从低温（200 K）到高温（373 K）范围内进行的变温电输运测量证明了金属导电。有趣的是，三维MOF，即CuTCNQ（TCNQ = 7,7,8,8 - 四氰基对苯二醌二甲烷）的薄膜在装饰AgNPs后呈现出相反的趋势。通过使用第一性原理密度泛函理论（DFT）计算理解了在AgNPs@Cu(HHTP)和AgNPs@CuTCNQ体系中这种独特观察结果的起源，并将其归因于界面电子效应。我们的工作为合理设计MOF薄膜中的合成修饰以调节电输运性质提供了新的思路。
