Book/Dissertation / PhD Thesis

FZJ-2015-05556

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Light Trapping with Plasmonic Back Contacts in Thin-Film Silicon Solar Cells

Paetzold, U. W. (Corresponding author)FZJ*

2013
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-89336-895-2

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Please use a persistent id in citations: http://hdl.handle.net/2128/10361

Abstract: Trapping light in silicon solar cells is essential as it allows an increase in the absorptionof incident sunlight in optically thin silicon absorber layers. This way, the costsof the solar cells can be reduced by lowering the material consumption and decreasingthe physical constraints on the material quality. In this work, plasmonic light trappingwith Ag back contacts in thin-film silicon solar cells is studied. Solar cell prototypeswith plasmonic back contacts are presented along with optical simulations of thesedevices and general design considerations of plasmonic back contacts.Based on three-dimensional electromagnetic simulations, the conceptual design ofplasmonic nanostructures on Ag back contacts in thin-film silicon solar cells is studiedin this work. Optimizations of the nanostructures regarding their ability to scatterincident light at low optical losses into large angles in the silicon absorber layers ofthe thin-film silicon solar cells are presented. Geometrical parameters as well as theembedding dielectric layer stack of the nanostructures on Ag layers are varied. Periodicas well as isolated hemispherical Ag nanostructures of dimensions above 200 nmare found to scatter incident light at high efficiencies and low optical losses. Hence,these nanostructures are of interest for light trapping in solar cells. In contrast, smallAg nanostructures of dimension below 100 nm are found to induce optical losses.At the surface of randomly textured Ag back contacts small Ag nanostructures existwhich induce optical losses. In this work, the relevance of these localized plasmoninduced optical losses as well as optical losses caused by propagating plasmons areinvestigated with regard to the reflectance of the textured back contacts. In state-ofthe-art solar cells, the plasmon-induced optical losses are shifted out of the relevantwavelength range by incorporating a ZnO:Al interlayer of low refractive index at theback contact. The additional but small potential for increasing the reflection at theback contact with dielectric interlayers of even lower refractive index, such as SiO$_{2}$ and air, is demonstrated.

Note: RWTH Aachen, Diss., 2013

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Contributing Institute(s):

1. Photovoltaik (IEK-5)

Research Program(s):

1. 121 - Solar cells of the next generation (POF3-121) (POF3-121)

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Database coverage:

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