Competitive Photochemical Reactivity in a Self-Assembled Monolayer on a Colloidal Gold Cluster

Hu, Jun; Zhang, Jian; Liu, Fang; Kittredge, Kevin W.; Whitesell, and James K.; Fox, Marye Anne

doi:10.1021/ja003180l

Cited by 124 publications

(111 citation statements)

References 36 publications

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“…17 The emission wavelength of bound fluorophores on the metal particles was slightly shifted to 662 nm with a simultaneous band broadening, which was probably due to a restriction of movement for the bound fluorophore. 38 The hybridized DNA duplex chains can be regarded as the rigid rods that separate the fluorophores from the surfaces of metal cores. Since the DNA used in the current experiment contains 23 base pairs, the separation between the fluorophore and metal core is about 8 nm.…”

Section: Resultsmentioning

confidence: 99%

Single-Molecule Studies on Fluorescently Labeled Silver Particles: Effects of Particle Size

et al. 2007

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We studied the dependence of single-molecule fluorescence on the size of nearby metal particles. The silver particles were synthesized with average diameters of metal cores being 5, 20, 50, 70, and 100 nm, respectively. A single-stranded oligonucleotide was chemically bound to a single silver particle and a Cy5-labeled complementary single-stranded oligonucleotide was hybridized with the particle-bound oligonucleotide. The space between the fluorophore and metal core was separated by a rigid hybridized DNA duplex of 8 nm length. The single fluorescence images and intensity traces were recorded by scanning confocal microscopy. The single fluorophore-labeled 50 nm silver particles displayed the most enhanced intensity, a factor of 17-fold increase relative to the free fluorophores in the absence of metal. Numerical simulations by the finite-difference time-domain (FDTD) method and results from Mie theory were used to compare with the experimental results. The 50 nm silver particles were also labeled by multiple fluorophores. The fluorescence intensity of multiple fluorophore-labeled metal particles increases dramatically with the loading number and reached 400-fold relative to the free single fluorophore when the loading number of fluorophore per metal particle was 50. The fluorophore also displayed better photostability when binding on the metal particle. These results can aid us to develop novel nanoscale fluorophores for clinical diagnostics and bioassay.

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Section: Resultsmentioning

confidence: 99%

Single-Molecule Studies on Fluorescently Labeled Silver Particles: Effects of Particle Size

et al. 2007

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“…First, direct electronic coupling of a nanoparticle core with a chromophore due to proximity (55) might result in the complete quenching of the photoreaction, and second, steric constraints, which limit the conformational freedom of the molecular entities immobilized, affect photochemistry to varying degrees depending on the system. For example, the trans-cis isomerization of azobenzenes and stilbenes, chemisorbed on gold nanoparticles via a range of alkylthiol linker chain lengths, has been described (58,59). In these studies a clear dependence of photochemical quantum yield on chain length was observed, which was assigned to a distance-dependent quenching of the excited state through electronic coupling with the metal nanoparticle.…”

Section: Photoswitchable Molecularly Modified Nanoparticlesmentioning

confidence: 99%

Light Switching of Molecules on Surfaces

Browne

Feringa

2009

Annu. Rev. Phys. Chem.

274

254

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Smart surfaces, surfaces that respond to an external stimulus in a defined manner, hold considerable potential as components in molecular-based devices, not least as discrete switching elements. Many stimuli can be used to switch surfaces between different states, including redox, light, pH, and ion triggers. The present review focuses on molecular switching through the electronic excitation of molecules on surfaces with light. In developing light-responsive surfaces, investigators face several challenges, not only in achieving high photostationary states and fully reversible switching, but also in dealing with fatigue resistance and the effect of immobilization itself on molecular properties. The immobilization of light-responsive molecules requires the design and synthesis of functional molecular components both to achieve light switching and to anchor the molecular entity onto a surface. This review discusses several demonstrative examples of photoswitchable molecular systems in which the photochemistry has been explored in the immobilized state under ambient conditions and especially on electroactive surfaces, including self-assembled monolayers, bilayers, and polymer films.

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“…Trans-cis isomerization of azobenzenes, [17][18][19] stilbenes [20] and overcrowded alkenes [21] chemisorbed on gold nanoparticles via alkylthiol linkers with a range of chain lengths have been reported. In these studies the effect of immobilisation on photochemical properties was of considerable interest both from molecule-surface and molecule-molecule interactions.…”

Section: Light Switching Of Molecules On Metallic Surfacesmentioning

confidence: 99%

Light and Redox Switchable Molecular Components for Molecular Electronics

Browne

Feringa

2010

Chimia

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Abstract:The field of molecular and organic electronics has seen rapid progress in recent years, developing from concept and design to actual demonstration devices in which both single molecules and self-assembled monolayers are employed as light-responsive components. Research in this field has seen numerous unexpected challenges that have slowed progress and the initial promise of complex molecular-based computers has not yet been realised. Primarily this has been due to the realisation at an early stage that molecular-based nano-electronics brings with it the interface between the hard (semiconductor) and soft (molecular) worlds and the challenges which accompany working in such an environment. [1][2][3] Issues such as addressability, cross-talk, molecular stability and perturbation of molecular properties (e.g. inhibition of photochemistry) have nevertheless driven development in molecular design and synthesis as well as our ability to interface molecular components with bulk metal contacts to a very high level of sophistication. Numerous groups have played key roles in progressing this field not least teams such as those led by Whitesides, [1] Aviram, Ratner, [4] Stoddart and Heath. [5] In this short review we will however focus on the contributions from our own group and those of our collaborators, [6] in employing diarylethene [7] based molecular components.

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Competitive Photochemical Reactivity in a Self-Assembled Monolayer on a Colloidal Gold Cluster

Cited by 124 publications

References 36 publications

Single-Molecule Studies on Fluorescently Labeled Silver Particles: Effects of Particle Size

Single-Molecule Studies on Fluorescently Labeled Silver Particles: Effects of Particle Size

Light Switching of Molecules on Surfaces

Light and Redox Switchable Molecular Components for Molecular Electronics

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