| 研究実績の概要 |
In this year we have investigated formation of metal-organic framework structures on thin film of Au deposited on a silicon surface. Two organic ligands were used: a 4,4-bipyridine (BiPy), and 1,2-di(4-pyridyl)ethylene (BPE). It has been confirmed that inorganic ion-templated gold surface can be used for formation of well defined metal-organic framework structures. The resultant structures have been investigated using scanning tunneling microscopy and Raman spectroscopy. They are made of protonated ligand molecule and a surface chloride compound which guides their self-assembly into three dimensional structures via attractive hydrogen bonding and aurophilic (Au-Au) interactions. The size of the three-dimensional structures is so far limited into islands of about 10 um. The small size of the islands at present precludes measurement of their I-V characteristics. The metal-organic framework structures composed of BPE ligand have interesting optical properties. They are found to absorb 360 nm light, emitting blue light at room temperature. It is expected that proper selection of organic ligand will allow for tuning wavelength of the adsorbed light allowing for harvesting photons with the energy that can be absorbed by a silicon substrate.
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