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Optical optimization of high resistance transparent layers in thin film cadmium telluride solar cells
journal contribution
posted on 2016-12-19, 14:54 authored by Gerald Womack, Piotr Kaminski, Michael WallsMichael WallsThin film photovoltaic devices are multilayer opto-electrical structures in which light interference occurs. Light reflection at the interfaces and absorption within the window layers reduces transmission and, ultimately, the conversion efficiency of photovoltaic devices. Optical reflection losses can be reduced by adjusting the layer thicknesses to achieve destructive interference within the structure of the cell. The light transmission to the CdTe absorber of a CdS/CdTe cell on a fluorine doped tin oxide transparent conductor has been modeled using the transfer matrix method. The interference effect in the CdS layer and high resistance transparent buffer layers (SnO2 and ZnO) has been investigated. The modeling shows that due to relatively high absorption within the SnO2 layer, there are modest benefits to engineering anti-reflection interference in the stack. However, a ZnO buffer layer has limited absorption and interference can be exploited to provide useful anti-reflection effects. Optical modeling and optimization shows that for a 50 nm CdS layer, a maximum transmission of 78.5% is possible using ZnO as a buffer layer at 58 nm thickness, and 78.0% for a SnO2 buffer layer at a thickness of 48 nm.
Funding
The authors are grateful to UKERC for funding this work through the EPSRC Supergen SuperSolar Hub, grant number: EP/J017361/1. One of the authors (GW) is grateful to Loughborough University Graduate School and NSIRC Ltd for supporting a CASE studentship.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Research Unit
- Centre for Renewable Energy Systems Technology (CREST)
Published in
VacuumCitation
WOMACK, G., KAMINSKI, P.M. and WALLS, J.M., 2016. Optical optimization of high resistance transparent layers in thin film cadmium telluride solar cells. Vacuum, 139, pp. 196–201.Publisher
© ElsevierVersion
- AM (Accepted Manuscript)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Acceptance date
2016-11-25Publication date
2016Notes
This paper was accepted for publication in the journal Vacuum and the definitive published version is available at http://dx.doi.org/10.1016/j.vacuum.2016.11.031.ISSN
0042-207XPublisher version
Language
- en
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