International Journal of Thermophysics

, Volume 34, Issue 10, pp 1930–1952

Design and Analysis of Spectrally Selective Patterned Thin-Film Cells



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.


Fabrication error Inverse optimization Sensitivity analysis  Thin-film solar cells 

List of Symbols



Variable in Eq. 7


Enhancement factor


Objective function


Height of silver nanowires


Height of amorphous silicon


Hermite polynomial of order \(N\)


Solar irradiance spectrum


Sigma points for the unscented transform


Number of satisfied moments in unscented transform


Sigma weights for the unscented transform


Width of silver nanowires


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

\(\lambda \)


\(\gamma _i, \lambda _i\)

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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