scholarly journals Measuring Local Electric Fields and Local Charge Densities at Electrode Surfaces Using Graphene-Enhanced Raman Spectroscopy (GERS)-Based Stark-Shifts

2019 ◽  
Vol 11 (39) ◽  
pp. 36252-36258 ◽  
Author(s):  
Haotian Shi ◽  
Bofan Zhao ◽  
Jie Ma ◽  
Mark J. Bronson Jr ◽  
Zhi Cai ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Electric Fields ◽  
Charge Densities ◽  
Electrode Surfaces ◽  
Local Charge

Measurement of electric fields at electrode surfaces

1965 ◽  
Vol 1 (4) ◽  
pp. 110 ◽  
Author(s):  
J.M. Meek ◽  
M.M.C. Collins
Keyword(s):  
Electric Fields ◽  
Electrode Surfaces

scholarly journals Refractive index sensing and surface-enhanced Raman spectroscopy using silver–gold layered bimetallic plasmonic crystals

2017 ◽  
Vol 8 ◽  
pp. 2492-2503 ◽  
Author(s):  
Somi Kang ◽  
Sean E Lehman ◽  
Matthew V Schulmerich ◽  
An-Phong Le ◽  
Tae-woo Lee ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Refractive Index ◽  
Electric Fields ◽  
Surface Enhanced Raman Spectroscopy ◽  
Plasmonic Crystals ◽  
Metal Thickness ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Difference Time

Herein we describe the fabrication and characterization of Ag and Au bimetallic plasmonic crystals as a system that exhibits improved capabilities for quantitative, bulk refractive index (RI) sensing and surface-enhanced Raman spectroscopy (SERS) as compared to monometallic plasmonic crystals of similar form. The sensing optics, which are bimetallic plasmonic crystals consisting of sequential nanoscale layers of Ag coated by Au, are chemically stable and useful for quantitative, multispectral, refractive index and spectroscopic chemical sensing. Compared to previously reported homometallic devices, the results presented herein illustrate improvements in performance that stem from the distinctive plasmonic features and strong localized electric fields produced by the Ag and Au layers, which are optimized in terms of metal thickness and geometric features. Finite-difference time-domain (FDTD) simulations theoretically verify the nature of the multimode plasmonic resonances generated by the devices and allow for a better understanding of the enhancements in multispectral refractive index and SERS-based sensing. Taken together, these results demonstrate a robust and potentially useful new platform for chemical/spectroscopic sensing.

Sensing local pH and ion concentration at graphene electrode surfaces using in situ Raman spectroscopy

Nanoscale ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 2398-2403 ◽  
Author(s):  
Haotian Shi ◽  
Nirakar Poudel ◽  
Bingya Hou ◽  
Lang Shen ◽  
Jihan Chen ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Ion Concentration ◽  
In Situ Raman Spectroscopy ◽  
Electrode Surfaces ◽  
In Situ Raman ◽  
Graphene Electrode ◽  
Novel Approach ◽  
Local Ph

We report a novel approach to probe the local ion concentration at graphene/water interfaces using in situ Raman spectroscopy.

scholarly journals Inhomogeneity of Interfacial Electric Fields at Vibrational Probes on Electrode Surfaces

2020 ◽  
Vol 6 (2) ◽  
pp. 304-311 ◽  
Author(s):  
Zachary K. Goldsmith ◽  
Maxim Secor ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Electric Fields ◽  
Electrode Surfaces

Self and Directed Colloidal Assembly on Patterned Electrodes

2005 ◽  
Author(s):  
P. Bahukudumbi ◽  
Michael A. Bevan ◽  
Ali Beskok
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Colloidal Particle ◽  
Three Dimensional ◽  
Directed Assembly ◽  
Ordered Structures ◽  
Colloidal Assembly ◽  
Electrode Surfaces ◽  
External Electric Fields ◽  
Potential Energy Landscapes

Clustering of colloidal particles near an electrode surface during and after electrophoretic deposition has been reported in the literature [1, 2, 3, 4]. The aggregation of colloidal particles has made the precise assembly of two and three dimensional colloidal crystals possible. In this paper, we demonstrate the use of external electric fields to sensitively tune the interactions between colloidal particles to form ordered structures. The directed assembly of colloidal particles on patterned electrode surfaces is also investigated as a means of building three-dimensional nanostructures. Finally, a new method to map potential energy landscapes of templated substrates using a diffusing colloidal particle as a sensitive local energy probe is described.

scholarly journals Charge Densities above Pulsar Polar Caps

2000 ◽  
Vol 177 ◽  
pp. 463-464
Author(s):  
A. Jessner ◽  
H. Lesch ◽  
Th. Kunzl
Keyword(s):  
Neutron Star ◽  
Electric Field ◽  
Work Function ◽  
Potential Barrier ◽  
Electric Fields ◽  
Surface Potential ◽  
Thermal Emission ◽  
Equilibrium Density ◽  
Charge Densities ◽  
Polar Caps

A simplified model provided the framework for our investigation into the distribution of energy and charge densities above the polar caps of a rotating neutron star. We assumed a neutron star withm= 1.4M⊙,r= 10km, dipolar field |B0| = 1012G,B||Ω and Ω = 2Π · (0.5s)−1. The effects of general relativity were disregarded. The induced accelerating electric fieldE||reachesE0= 2.5 · 1013V m−1at the surface near the magnetic poles. The current density along the field lines has an upper limitnGJ, when the electric field of the charged particle flow cancels the induced electric field: At the polesnGJ(r=rns,θ= 0) = 1.4 · 1017m−3.The work function(surface potential barrier)EWis approximated by the Fermi energyEFof magnetised matter. Following Abrahams and Shapiro (1992) one needs to revise the surface density from the canonical 1.4 · 108kg m−3down toρFe = 2.9 · 107kg m−3. Withwe obtain a value ofEF=Ew= 417eV. There are two relevant particle emission processes:Field (cold cathode) emissionby quantum-mechanical tunneling of charges through the surface potentialandthermal emissionwhich is a purely classical process. In strong electric fields it is enhanced by the lowering of the potential barrier due to the Schottky effect. The combined Dushman-Schottky equationwithtells us, thatat temperatures> 2 · 105K the the Goldreich-Julian current can be supplied thermal emission alone. The surface temperature however has a lower limit in the order of 105K due to the rotational braking. Therefore, in most cases a sufficient supply of charges for the Goldreich-Julian current is available and the electrical field accelerating the particles will be quenched as a result of their abundance. Otherwise a residual equilibrium electric field Eeqremains with:and hence the equilibrium density is:n=nfieid(Eeq,EW) +nDS(Eeq,EW,T) For a temperature just below the onset of thermal emission (T= 1.85 · 105K) the charge density is found to vary almost linearly with the work functionEWfor values ofEWbetween 0.3 and 2 keV. At the chosen value forEWof 417 eVthe residual electric field amounts to only 8.5% of the vacuum value. Even in the residual electric field the particles are rapidly accelerated to relativistic energies balanced by inverse Compton and curvature radiation losses.

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