Charge Transfer-Induced Molecular Hole Doping into Thin Film of Metal鈥揙rganic Frameworks

详细信息    查看全文

• 作者：Deok Yeon Lee ; Eun-Kyung Kim ; Nabeen K. Shrestha ; Danil W. Boukhvalov ; Joong Kee Lee ; Sung-Hwan Han
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 26, 2015
• 年：2015
• 卷：7
• 期：33
• 页码：18501-18507
• 全文大小：332K
• ISSN：1944-8252

文摘

Despite the highly porous nature with significantly large surface area, metal鈥搊rganic frameworks (MOFs) can be hardly used in electronic and optoelectronic devices due to their extremely poor electrical conductivity. Therefore, the study of MOF thin films that require electron transport or conductivity in combination with the everlasting porosity is highly desirable. In the present work, thin films of Co₃(NDC)₃DMF₄ MOFs with improved electronic conductivity are synthesized using layer-by-layer and doctor blade coating techniques followed by iodine doping. The as-prepared and doped films are characterized using FE-SEM, EDX, UV/visible spectroscopy, XPS, current鈥搗oltage measurement, photoluminescence spectroscopy, cyclic voltammetry, and incident photon to current efficiency measurements. In addition, the electronic and semiconductor properties of the MOF films are characterized using Hall Effect measurement, which reveals that, in contrast to the insulator behavior of the as-prepared MOFs, the iodine doped MOFs behave as a p-type semiconductor. This is caused by charge transfer-induced hole doping into the frameworks. The observed charge transfer-induced hole doping phenomenon is also confirmed by calculating the densities of states of the as-prepared and iodine doped MOFs based on density functional theory. Photoluminescence spectroscopy demonstrates an efficient interfacial charge transfer between TiO₂ and iodine doped MOFs, which can be applied to harvest solar radiations.