Charge Transfer Rates at a Bio鈥揑norganic Interface

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• 作者：Wenming Sun ; Andrea Ferretti ; Daniele Varsano ; Giorgia Brancolini ; Stefano Corni ; Rosa Di Felice
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 14, 2014
• 年：2014
• 卷：118
• 期：32
• 页码：18820-18828
• 全文大小：422K
• ISSN：1932-7455

文摘

We have investigated the role of molecular bridges in determining the electronic structure and transfer rates at interfaces in which natural or expanded guanine is attached through a thiol bond to a Au(111) surface as a model for charge injection at the DNA@Au interface. Our study is based on van der Waals-corrected ab initio density functional theory calculations. We have considered two linkers with different length and chemistry. We find that the shorter linker allows for a larger electronic coupling between the metal and the guanine, with a modulation of 3 orders of magnitude. The aromatic size expansion of guanine further enhances the electronic coupling by a factor of 2. Our findings demonstrate that even in the case of potentially through-bond charge transfer, the donor鈥揳cceptor distance regulates the electronic coupling. Furthermore, we establish a procedure for computing the donor鈥揳cceptor coupling between delocalized metal states and localized molecular states.