Theory for Potential of Zero Charge and Capacitance on Metals with Nanocorrugated Steps

Abstract

We develop the mean-field theory for the step density-induced anomalous variation in electronic capacitance, work function (WF), potential of zero charge (PZC), and interfacial capacitance (IC) of an electrode. The random nanocorrugated step geometry has the functional form as a hyperbolic tangent with a random step edge. The average PZC and IC along with WF expression is obtained as a function of mean-square gradient and mean curvatures. The theoretical result highlights the anomalous non-monotonic lowering of the average PZC and WF with increasing step density. This explains the experimental observation for the stepped platinum electrodes. Further, this theory shows nanocorrugation and the nature of metal-driven large suppression in an average WF of ≈ 0.7 eV, a PZC of ≈ 0.5 eV, and an IC of ≈ 1.4 μF/cm2 from its planar value. Finally, this theory predicts that the step curvature and the step density cause significant variation in electronic WF and PZC, which is consequently the genesis of many anomalies in surface and interfacial phenomena.

Semi-microscopic Theory for the Current Rectification Phenomenon in Nanogap Molecular Devices

“… a One of the electrode/SAM interfaces is fixed as Au/C 8 , and the other electrode/SAM junction energy is altered with Au/DTC- n , varying SAMs from DTC-1 to DTC-9. We report the variation in interface energetics with different molecular self-assemblies at the Au surface with ϕ E 0 = 5.31 eV, E F = 5.53 eV, l TF = 0.123 nm, and ϵ m = 4.39. , The reported values are estimated for the monolayer coverage (θ = 1) of self-assembled molecules with coverage to N 0 = 4.3 nm –2 corresponding to r d = 0.27 nm. The magnitude of the HOMO energy of the electroactive molecule is taken as 5.2 eV .…”

“…The electronic WF of an electrode is a jellium surface property that varies with the surface modification, the step and kink density, 46 nanostructuring, 33,34 doping with foreign atoms, The Journal of Physical Chemistry A molecular adsorption, 31,32,36 and so on. A wide range of variation in the WF can be achieved through introducing molecular self-assembly over the same metal surface.…”

“…The electronic WF of an electrode is a jellium surface property that varies with the surface modification, the step and kink density, nanostructuring, , doping with foreign atoms, molecular adsorption, ,, and so on. A wide range of variation in the WF can be achieved through introducing molecular self-assembly over the same metal surface. , Kant et al , developed the formulation of the WF in the presence of solvent as well as molecular self-assembled dipoles and observed the significant variation in the WF only up to the monolayer molecular adsorption.…”

Theory for Heterogeneous Electron Transfer Kinetics on Nanocorrugated Atomic Stepped Metal Electrodes

“…The third term in eq accounts for the packing correction on curved metal surface covered with dipolar solvent which is given by , g s ( x , y ) = θ g s 0 [ 1 + 2 H ′ false( x , y false) r d + K ′ false( x , y false) r d 2 ] Equation accounts for the local curvature dependent contribution from dipolar solvents at the step edge. The special case of eq for H ′( x , y ) = 0 and K ′( x , y ), is the average dipolar contribution of the basal plane.…”

Theory for nanoscale curvature induced enhanced inactivation kinetics of SARS-CoV-2

“…The δ ≠ in eqn ( 8) and ( 9) is the fractional electronic charge exchange at the transition state and it is always taken to be positive in the estimation of the activation free energy. The WF of a metal surface can be tailored in several ways, mainly by introducing nanostructures with different sizes, shapes, atomic steps, and molecular self-assembly, [50][51][52][53] which, consequently, will alter the activation energy of the ET process. The electrode surface curvature dependent activation free energy for heterogeneous ET kinetics is discussed in the following part.…”