Single-Molecule Optoelectronics

Lee, Tae Hee; González, José Ignacio Rodríguez; Zheng, Jie; Dickson, Robert M.

doi:10.1021/ar040146t

Cited by 216 publications

(170 citation statements)

References 76 publications

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“…7 The stoichiometry/size-dependent variations in the energy levels of the silver nanoclusters will be utilized for single-molecule electronics and fluorescence labeling. 9 In these studies, the use of the cytosine oligonucleotide dC 12 was motivated by prior 1 H NMR spectra in which the silver nanoclusters caused significant spectral shifts for cytosine in comparison with other bases. 10 Multiple species are formed following reduction of the Ag + bound to dC 12 , and a key distinction is the extent of reduction of these nanoclusters.…”

Section: Introductionmentioning

confidence: 99%

Ag Nanocluster Formation Using a Cytosine Oligonucleotide Template

et al. 2006

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The reduction of silver cations bound to the oligonucleotide dC 12 was used to form silver nanoclusters. Mass spectra show that the oligonucleotides have 2-7 silver atoms that form multiple species, as evident from the number of transitions in the fluorescence and absorption spectra. The variations in the concentrations of the nanoclusters with time are attributed to the changing reducing capacity of the solution, and the formation of oxidized nanoclusters is proposed. Via mass spectrometry and circular dichroism spectroscopy, double-stranded structures with Ag + -mediated interactions between the bases are observed, but these structures are not maintained with the reduced nanoclusters. Through variations in the pH, the nanoclusters are shown to bind with the N3 of cytosine.

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Section: Introductionmentioning

confidence: 99%

Ag Nanocluster Formation Using a Cytosine Oligonucleotide Template

et al. 2006

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“…In this case, we focus on the nearinfrared emitters using 633 nm as the excitation wavelength. Although a number of single molecule studies have been performed on AgNC to investigate specifi c photophysical parameters, [ 5,6,8,10,14,25,[27][28][29][30][31][32][33] we simultaneously measure several photophysical properties for each individual cluster, including decay times, emission spectra, and antibunching. This allows us to compare and correlate these photophysical properties within a sample to better understand the photophysical behavior and heterogeneity of these complex as-synthesized AgNC samples.…”

Section: Introductionmentioning

confidence: 99%

Single‐Molecule Characterization of Near‐Infrared‐Emitting Silver Nanoclusters

Hooley

Paolucci

Liao

et al. 2015

Advanced Optical Materials

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In this paper, single molecule spectroscopy is used to probe the photophysical heterogeneity of near‐infrared emitting silver nanoclusters stabilized in single stranded DNA containing 24 cytosines (C24‐AgNCs). Focusing on this subset of emitters allows us to address and correlate their photophysical parameters. The results suggest that for these near‐infrared emitting C24‐AgNCs, the broad range of observed photophysical properties is due to the spectral heterogeneity of two species, one of which has a broad range of emission maxima and decay times. This conclusion is drawn by analyzing the results of a large number of single C24‐AgNCs where, for the first time, emission maxima, fluorescence decay times, fluorescence intensity, blinking, and photon antibunching are determined simultaneously. The single molecule measurements also reveal that some of the C24‐AgNCs can change their spectral properties during the measurement, while photon antibunching measurements verified that all the analyzed C24‐AgNCs behave as single emitters. While the overall spectral heterogeneity can be related to the immobilization in the polymer film and/or intrinsic heterogeneity of the C24‐AgNCs emitters, the exact origin of the dynamical changes has not been fully determined. However, changes in the AgNCs geometry, local environment, or changes in the DNA conformation are possible explanations.

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“…1,2 As their size approaches the Fermi wavelength (ca. 0.5 nm) of electrons, gold and silver nanoclusters display molecule-like emission.…”

Section: ■ Introductionmentioning

confidence: 99%

Template Synthesis of Subnanometer Gold Clusters in Interfacially Cross-Linked Reverse Micelles Mediated by Confined Counterions

Zhang

Zhao

2012

Langmuir

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A cationic surfactant with a triallylammonium headgroup was cross-linked photochemically in the presence of a hydrophilic dithiol in the reverse micelle (RM) configuration. The interfacially cross-linked reverse micelles (ICRMs) are unusual templates for nanomaterials synthesis. Our previous work indicated that the ICRMs could extract anionic metal salts such as tetracholoroaurate into the hydrophilic interior, and the entrapped aurate was reduced without externally added reducing agent to form subnanometer luminescent gold clusters Zhao, Y. ACS Nano2011, 5, 2637. In this work, the bromide counterions were established as the reducing agent in the template synthesis. The reduction of tetrachloroaurate was proposed to happen through ligand exchange on the aurate by the bromide ions, reductive elimination of halogen, and disproportionation of the Au(I) intermediate. The size of the gold clusters could be tuned rationally by the water-to-surfactant ratio (W0) and the reducing agent. Monodisperse Au4 and Au9-10 clusters as well as larger Au18 and Au23 clusters were obtained from the ICRM templates. The as-prepared, metastable gold clusters were subject to reconstruction triggered by ligand exchange on the surface but could be stabilized through proper surface protection using a chelating dithiol. Disciplines Chemistry CommentsReprinted (adapted) with permission from Langmuir 28 (2012) ABSTRACT: A cationic surfactant with a triallylammonium headgroup was cross-linked photochemically in the presence of a hydrophilic dithiol in the reverse micelle (RM) configuration. The interfacially cross-linked reverse micelles (ICRMs) are unusual templates for nanomaterials synthesis. Our previous work indicated that the ICRMs could extract anionic metal salts such as tetracholoroaurate into the hydrophilic interior, and the entrapped aurate was reduced without externally added reducing agent to form subnanometer luminescent gold clusters Zhao, Y. ACS Nano 2011. In this work, the bromide counterions were established as the reducing agent in the template synthesis. The reduction of tetrachloroaurate was proposed to happen through ligand exchange on the aurate by the bromide ions, reductive elimination of halogen, and disproportionation of the Au(I) intermediate. The size of the gold clusters could be tuned rationally by the water-to-surfactant ratio (W 0 ) and the reducing agent. Monodisperse Au 4 and Au 9−10 clusters as well as larger Au 18 and Au 23 clusters were obtained from the ICRM templates. The as-prepared, metastable gold clusters were subject to reconstruction triggered by ligand exchange on the surface but could be stabilized through proper surface protection using a chelating dithiol.

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Single-Molecule Optoelectronics

Cited by 216 publications

References 76 publications

Ag Nanocluster Formation Using a Cytosine Oligonucleotide Template

Ag Nanocluster Formation Using a Cytosine Oligonucleotide Template

Single‐Molecule Characterization of Near‐Infrared‐Emitting Silver Nanoclusters

Template Synthesis of Subnanometer Gold Clusters in Interfacially Cross-Linked Reverse Micelles Mediated by Confined Counterions

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