Disentangling the Photophysics of DNA-Stabilized Silver Nanocluster Emitters

Abstract

It has been already established that DNA−silver fluorophores present two intense absorption bands, one in the visible and the other in the UV spectral region, and that the excitation of both bands produces a common fluorescence signal. Nevertheless, the detailed mechanism responsible for this coupling is still elusive. In this context, our work is a significant leap forward in this goal by providing a dynamic picture of the excitation and the processes that take place upon light absorption in these systems using a time-dependent density functional tight-binding approach. In the present work, we explore the electronic coupling mechanism in a cluster composed of a double string of deoxypolycytosine with six bases and a rod of six Ag atoms.

Chiral Noble Metal Nanoparticles and Nanostructures

“…Berdakin and co‐workers studied the electronic and optical properties of Ag:DNA clusters using Molecular Dynamics and density functional‐based tight binding (DFTB) methods . Two model structures of neutral Ag 6 stabilized by DNA were considered: i) (dpC 6 ) 2 Ag 6 where two strings of deoxypolycytosine with six bases protect a rod of six Ag atoms and ii) (C 2 Ag) 6 structure without the phosphate and ribose backbone (metal‐mediated base pair only) ( Figure ).…”

“…Red lines show the absorption spectra of the DNA moieties of each structure. Adapted with permission . Copyright 2017, the Owner Societies.…”

“…[98,99] Berdakin and co-workers studied the electronic and optical properties of Ag:DNA clusters using Molecular Dynamics and density functional-based tight binding (DFTB) methods. [100] Two model structures of neutral Ag 6 stabilized by DNA were Figure 26. Examples of the Ag:DNA structures.…”

Fluorescent DNA‐Templated Silver Nanoclusters from Silver(I)‐Mediated Base Pairs

“…As expected, no luminescence was detected for duplex II ( Figure S5). [14] The emission spectra of the DNA-templated AgNCs display one broad band at around 600 nm, except for the system derived fromd uplex IV,w here the emission maximum was observeda t5 40 nm ( Figure 3, Table 1). [11] Onlyd uplexes providing cytosine residues as Ag I -binding sites give rise to fluorescent AgNCs.…”

Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine

“…45 Additional work focuses on the electronic and optical properties of DNA-AgNCs, 2,46 charge transfer optical absorption mechanisms, 47 and the photophysics of the excitation process involved in DNA-AgNCs. 48 Despite the extensive experimental and theoretical work on the DNA-AgNC systems, the binding interaction of the Ag n nanoclusters with the base pairs is still not fully understood. Further progress of DNA-AgNC nanomaterials is hindered by the limited understanding of the cluster structure.…”