International Journal of Thermophysics

, Volume 34, Issue 10, pp 1930–1952

Design and Analysis of Spectrally Selective Patterned Thin-Film Cells

Article

Abstract

This paper outlines several techniques for systematic and efficient optimization as well as sensitivity assessment to fabrication tolerances of surface texturing patterns in thin film amorphous silicon (a-Si) solar cells. The aim is to achieve maximum absorption enhancement. The joint optimization of several geometrical parameters of a three-dimensional lattice of periodic square silver nanoparticles, and an absorbing thin layer of a-Si, using constrained optimization tools and numerical FDTD simulations is reported. Global and local optimization methods, such as the Broyden–Fletcher–Goldfarb–Shanno quasi-Newton method and simulated annealing, are employed concurrently for solving the inverse near-field radiation problem. The design of the silver-patterned solar panel is optimized to yield maximum average enhancement in photon absorption over the solar spectrum. The optimization techniques are expedited and improved using a novel nonuniform adaptive spectral sampling technique. Furthermore, the sensitivity of the optimally designed parameters of the solar structure is analyzed by postulating a probabilistic model for the errors introduced in the fabrication process. Monte Carlo simulations and unscented transform techniques are used for this purpose.

Keywords

Fabrication error Inverse optimization Sensitivity analysis  Thin-film solar cells 

List of Symbols

Variables

\(a\)

Variable in Eq. 7

\(E\)

Enhancement factor

\(f\)

Objective function

\(h_{\mathrm{Ag}}\)

Height of silver nanowires

\(h_{\mathrm{Si}}\)

Height of amorphous silicon

\(H_n\)

Hermite polynomial of order \(N\)

\(I\)

Solar irradiance spectrum

\(S_i\)

Sigma points for the unscented transform

\(T\)

Number of satisfied moments in unscented transform

\(w_i\)

Sigma weights for the unscented transform

\(w_{\mathrm{Ag}}\)

Width of silver nanowires

\({\varvec{x}}\)

Selected geometry

\(\Vert {\varvec{x}} \Vert \)

Norm of vector \({\varvec{x}}\)

Greek Symbols

\(\alpha _{\mathrm{gr}}\)

Spectral absorptivity in the presence of grating

\(\alpha _{\mathrm{ngr}}\)

Spectral absorptivity in the absence of grating

\(\lambda \)

Wavelength

\(\gamma _i, \lambda _i\)

Predefined constants

\(\Delta {\varvec{x}}\)

Change in \({\varvec{x}}\)

\(\varLambda _{\mathrm{Ag}}\)

Nanowires period

\(\varOmega \)

Optical wavelength range

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.University of Texas at AustinAustinUSA

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