On Modeling of Plasmon-Induced Enhancement of the Efficiency of Solar Cells Modified by Metallic Nano-Particles.

K Kluczyk,W Jacak,J Jacak,C David

doi:10.3390/nano9010003

Abstract

We demonstrate that the direct application of numerical packets like Comsol to plasmonic effect in solar cells metallically modified in nano-scale may be strongly inaccurate if quantum corrections are neglected. The near-field coupling of surface plasmons in metallic nanoparticles deposited on the top of a solar cell with band electrons in a semiconductor substrate strongly enhances the damping of plasmons in metallic components, which is not accounted for in standard numerical packets using the Drude type dielectric function for metal (taken from measurements in bulk or in thin layers) as the prerequisite for the numerical e-m field calculus. Inclusion of the proper corrections to plasmon damping causes additional enhancement of the plasmon-induced photo-effect efficiency growth of a metalized photo-diode by ten percent, at least, in comparison to only effect induced by the electric field concentration near metallic nanoparticles. This happens to be consistent with the experimental observations which cannot be explained by only local increases of the electrical field near the curvature of metallic nanoparticles determined by a finite-element solution of the Maxwell–Fresnel boundary problem as given by a numerical system like Comsol. The proper damping rate for plasmons can be identified by application of the Fermi Golden Rule approach to the plasmon-band electron coupling. We demonstrate this effect including the material and size dependence in two types of solar cells, multi-crystalline Si and CIGS (copper-indium-gallium-diselenide) as idealized photo-diode semiconductor substrate modified by various metallic nano-particles, in comparison to the experimental data and Comsol simulation.

Highlights

Plasmons in metallic nanoparticles have been the focus of growing attention because of their applications in sub-diffraction manipulation of light and related perspectives for the miniaturization of opto-electronic circuits [1,2,3,4,5,6] and advances in photovoltaics [7,8,9,10,11] for the improvement of the efficiency of new generation solar cells via low cost metallic nano-components
The strengthening of the sun-light energy harvesting in solar cells mediated by surface plasmons in metal-nano-particles deposited on photo-active solar cell surface is caused by three effects: (1) the strong concentration of the electric field of the incident photon e-m wave close to the metallic components with a large local curvature, (2) the large amplitude of plasmon oscillations in metallic nanoparticles, and (3) the enhancement of the probability of interband transitions in a semiconductor substrate caused by the breaking of the translational symmetry for a nanoparticle coupled in the near-field regime of surface plasmons with
We summarize the theoretical description of the plasmon-aided photo-effect and compare the mostly analytical model with the numerical simulation of the metallically nano-improved solar cells upon the commercial numerical system Comsol

Summary

Introduction

Plasmons in metallic nanoparticles have been the focus of growing attention because of their applications in sub-diffraction manipulation of light and related perspectives for the miniaturization of opto-electronic circuits [1,2,3,4,5,6] and advances in photovoltaics [7,8,9,10,11] for the improvement of the efficiency of new generation solar cells via low cost metallic nano-components. A large error is caused by the negligence in classical methods of the very effective quantum channel for energy transfer between plasmons in metallic nanoparticles and band electrons in a semiconductor substrate This channel can be accounted for in terms of the Fermi golden rule applied to inter-band transition of electrons in the semiconductor substrate induced by coupling to plasmons excited by the incident solar-light photons in metallic nanoparticles deposited on the photo-active surface. This channel for the energy transfer accurs to be highly effective and overwhelming the solar-light absorption in solar cells metallically modified in the nano-scale. The irradiation to the far-field zone toward the upper hemisphere (i.e., the Lorentz friction for the plasmon) is smaller than the near-field zone energy transfer to the substrate [15]

The Efficiency of the Plasmon-Mediated Photo-Effect

Numerical Modeling of Plasmon Photo-Effect by Comsol

Comparison with Experiment

Findings

Conclusions