Book/Dissertation / PhD Thesis

FZJ-2016-02871

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Light Management by Intermediate Reflectors in Silicon-based Tandem Solar Cells

Hoffmann, A. (Corresponding author)FZJ*

2016
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-186-6

Please use a persistent id in citations: http://hdl.handle.net/2128/13996

Abstract: Multijunction solar cells provide a route to further increase the efficiency of solar cells. By stacking different band-gap materials, thermalization losses can be decreased. Maximizing the effciency of series-connected multijunction solar cells gets complex as a variety of different layers is involved. The application of nano-scale textures which scatter and diffract the light in order to increase the light path and absorption. An advanced light management combining light trapping and spectral distribution is necessary to gain maximal output. In this work, light management in silicon-based multijunction solar cells by intermediate reflectors (IR) is studied. As soon as the thickness of absorber layers in multijunction devices is physically limited, IRs increase the light path in the sub cells and contribute to the matching of currents and power of the sub cells in series-connected multijunction solar cells. As each element added to a working device increases its complexity, the understanding of their interplay and underlying loss mechanisms is crucial to obtain an improvement of the device. Thin-film silicon tandem solar cells made of hydrogenated amorphous and microcrystalline silicon (also called 'micromorph') are chosen as model system for the analysis of the optics in silicon-based multijunction solar cells, as they are a well established industrially up-scalable technology and exhibit the important characteristics of other multijunction cell material systems: Thin-film layers, nano-structured surfaces, as well as physical limitations of thicknesses and a broad utilization of the solar spectrum. The combination of thin-film layer stack and nano-structured surfaces demands for a treatment of the solar cell as a nano-optical device. Motivated by the results of experimental studies, tandem solar cells are modeled by thin-film optics and rigorous optical simulations. An agreement between simulation to experimental results allows for an investigation and optimization of these devices. [...]

Note: RWTH Aachen, Diss., 2016

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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)

Appears in the scientific report 2016

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