International Journal of Thermophysics

, Volume 34, Issue 10, pp 1930–1952

Design and Analysis of Spectrally Selective Patterned Thin-Film Cells

Article

DOI: 10.1007/s10765-013-1495-y

Cite this article as:
Hajimirza, S. & Howell, J.R. Int J Thermophys (2013) 34: 1930. doi:10.1007/s10765-013-1495-y

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 errorInverse optimizationSensitivity 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