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Complex beam profiles for laser annealing of thin-film CdTe photovoltaics

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journal contribution
posted on 28.09.2018 by Nick Goffin, John Tyrer, Elliot Woolley
Within the family of thin-film photovoltaics (PV), cadmium telluride (CdTe) has the fastest growing market share due to its high efficiencies and low cost. However, as with other PV technologies, the energy required to manufacture the panels is excessive, encompassing high environmental impact and manufacturing energy payback times of the order of 2-3 years. As part of the manufacturing process, the panels are annealed at temperatures of approximately 400°C for 30 minutes, which is inherently inefficient. Laser heating has previously been investigated as an alternative process for thin film annealing, due to its advantages with regard to its ability to localise heat treatment, anneal selectively and its short processing time. In this investigation, results focussing on improvements to the laser-based annealing process, designed to mitigate panel damage by excessive thermal gradients, are presented. Simulations of various laser beam profiles are created in COMSOL and used to demonstrate the benefit of laser beam shaping for thin film annealing processes. An enabling technology for this, the holographic optical element (HOE), is then used to experimentally demonstrate the redistribution of laser beam energy into an optimal profile for annealing, eliminating thermal concentrations.

Funding

This work was funded by the Engineering and Physical Sciences Research Council (EPSRC), as part of Grant Number EP/M014088/1.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Journal of Laser Applications

Citation

GOFFIN, N.J., TYRER, J.R. and WOOLLEY, E., 2018. Complex beam profiles for laser annealing of thin-film CdTe photovoltaics. Journal of Laser Applications, 30 (4), 042006.

Publisher

AIP Publishing © Laser Institute of America

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Acceptance date

18/09/2018

Publication date

2018-10-18

Notes

All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

ISSN

1042-346X

eISSN

1938-1387

Language

en

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