Structure and luminescence of DNA-templated silver clusters

Abstract

DNA can stabilize silver clusters with sequence-tuned fluorescence. We review recent advances in understanding of the structures and properties of DNA-templated silver clusters, their rational design and ordered arrangement, and emerging challenges.

Observation of microsecond luminescence while studying two DNA-stabilized silver nanoclusters emitting in the 800–900 nm range

“…While the exact composition of DNA841-AgNC and DNA811-AgNC is not known, it is reasonable to assume that more than one DNA strand stabilizes the AgNCs. More information on structure/spectroscopic property relationship of DNA-AgNCs can be found in a recent review by Gonzàlez-Rosell et al 1 For DNA841-AgNC an interesting observation was made as shown in Fig. 5.…”

“…Moreover, DNA811-AgNC displays a significant secondary transition around 470 nm, which is very atypical for rod-like DNA-AgNCs. 1,20 By using steady-state excitation and emission anisotropy measurements, we show that the 470 nm transition is parallel to the main transition at 640 nm for the DNA811-AgNC. This intriguing result could stimulate theoretical investigations and help to uncover the nature of the optical transitions in this class of emitters.…”

“…To the best of our knowledge, this is the first time that microsecond-lived luminescence has been observed for DNA-AgNCs. 1 It is well established that DNA-AgNCs have long-lived dark states with decay times in the microsecond range, but no significant emission has been associated with them. [30][31][32] In recent years, optical excitation of these dark states has been used in new imaging modalities such as optically activated delayed fluorescence (OADF) and upconversion fluorescence (UCF).…”

“…In recent years, the understanding of how DNA sequences select for emission color of DNA-stabilized silver nanoclusters (DNA-AgNCs) has advanced. 1 Evidence of preferred rod-like AgNCs was inferred by correlating emission color with the number of reduced silver atoms, yielding an increased prevalence of even numbers (e.g. 4Ag 0 for green and 6Ag 0 for red), 2 and by interpreting the shape of the absorption spectrum.…”

“…To the best of our knowledge, it is also the first time that microsecond luminescence has been reported for DNA-AgNCs (without active optical depopulation of long-lived dark states). 1,21,22…”