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Kincanon M, Murphy CJ. Nanoparticle Size Influences the Self-Assembly of Gold Nanorods Using Flexible Streptavidin-Biotin Linkages. ACS NANO 2023. [PMID: 38010073 DOI: 10.1021/acsnano.3c09096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The self-assembly of colloidal nanocrystals remains of robust interest due to its potential in creating hierarchical nanomaterials that have advanced function. For gold nanocrystals, junctions between nanoparticles yield large enhancements in local electric fields under resonant illumination, which is suitable for surface-enhanced spectroscopies for molecular sensors. Gold nanorods can provide such plasmonic fields at near-infrared wavelengths of light for longitudinal excitation. Through the use of careful concentration and stoichiometric control, a method is reported herein for selective biotinylation of the ends of gold nanorods for simple, consistent, and high-yielding self-assembly upon addition of the biotin-binding protein streptavidin. This method was applied to four different sized nanorods of similar aspect ratio and analyzed through UV-vis spectroscopy for qualitative confirmation of self-assembly and transmission electron microscopy to determine the degree of self-assembly in end-linked nanorods. The yield of end-linked assemblies approaches 90% for the largest nanorods and approaches 0% for the smallest nanorods. The number of nanorods linked in one chain also increases with an increased nanoparticle size. The results support the notion that the lower ligand density at the ends of the larger nanorods yields preferential substitution reactions at those ends and hence preferential end-to-end assembly, while the smallest nanorods have a relatively uniform ligand density across their surfaces, leading to spatially random substitution reactions.
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Affiliation(s)
- Maegen Kincanon
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Catherine J Murphy
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
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Medeghini F, Pettine J, Meyer SM, Murphy CJ, Nesbitt DJ. Regulating and Directionally Controlling Electron Emission from Gold Nanorods with Silica Coatings. NANO LETTERS 2022; 22:644-651. [PMID: 34989588 DOI: 10.1021/acs.nanolett.1c03569] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dielectric coatings offer a versatile means of manipulating hot carrier emission from nanoplasmonic systems for emerging nanocatalysis and photocathode applications, with uniform coatings acting as regulators and nonuniform coatings providing directional photocurrent control. However, the mechanisms for electron emission through dense and mesoporous silica (SiO2) coatings require further examination. Here, we present a systematic investigation of photoemission from single gold nanorods as a function of dense versus mesoporous silica coating thicknesses. Studies with dense coatings on gold nanostructures clarify the short (∼1 nm) attenuation length responsible for severely reduced transmission through the silica conduction band. By contrast, mesoporous silica is much more transmissive, and a simple geometric model quantitatively recapitulates the electron escape probability through nanoscopic porous channels. Finally, photoelectron velocity map imaging (VMI) studies of nanorods with coating defects verify that photoemission occurs preferentially through the thinner regions, illustrating new opportunities for designing photocurrent distributions on the nanoscale.
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Affiliation(s)
- Fabio Medeghini
- JILA, University of Colorado─Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
| | - Jacob Pettine
- JILA, University of Colorado─Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado─Boulder, Boulder, Colorado 80309, United States
| | - Sean M Meyer
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Catherine J Murphy
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - David J Nesbitt
- JILA, University of Colorado─Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado─Boulder, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado─Boulder, Boulder, Colorado 80309, United States
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Camden JP, Masiello DJ, Ren B. Spectroscopy and microscopy of plasmonic systems. J Chem Phys 2021; 155:090401. [PMID: 34496589 DOI: 10.1063/5.0065513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - David J Masiello
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Bin Ren
- Department of Chemistry, Xiamen University, Xiamen 361005, China
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Pettine J, Meyer SM, Medeghini F, Murphy CJ, Nesbitt DJ. Controlling the Spatial and Momentum Distributions of Plasmonic Carriers: Volume vs Surface Effects. ACS NANO 2021; 15:1566-1578. [PMID: 33427462 DOI: 10.1021/acsnano.0c09045] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Spatial and momentum distributions of excited charge carriers in nanoplasmonic systems depend sensitively on optical excitation parameters and nanoscale geometry, which therefore control the efficiency and functionality of plasmon-enhanced catalysts, photovoltaics, and nanocathodes. Growing appreciation over the past decade for the different roles of volume- vs surface-mediated excitation in such systems has underscored the need for explicit separation and quantification of these pathways. Toward these ends, we utilize angle-resolved photoelectron velocity map imaging to distinguish these processes in gold nanorods of different aspect ratios down to the spherical limit. Despite coupling to the longitudinal surface plasmon, we find that resonantly excited nanorods always exhibit transverse (sideways) multiphoton photoemission distributions due to photoexcitation within volume field enhancement regions rather than at the tip hot spots. This behavior is accurately reproduced via ballistic Monte Carlo modeling, establishing that volume-excited electrons primarily escape through the nanorod sides. Furthermore, we demonstrate optical control over the photoelectron angular distributions via a screening-induced transition from volume (transverse/side) to surface (longitudinal/tip) photoemission with red detuning of the excitation laser. Frequency-dependent cross sections are separately quantified for these mechanisms by comparison with theoretical calculations, combining volume and surface velocity-resolved photoemission modeling. Based on these results, we identify nanomaterial-specific contributions to the photoemission cross sections and offer general nanoplasmonic design principles for controlling photoexcitation/emission distributions via geometry- and frequency-dependent tuning of the volume vs surface fields.
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Affiliation(s)
- Jacob Pettine
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Sean M Meyer
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Fabio Medeghini
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
| | - Catherine J Murphy
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - David J Nesbitt
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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