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Wide GAP a-SiC:H Alloys for Novel Photovoltaic-Electrochromic Window Coatings

Published online by Cambridge University Press:  15 February 2011

John N. Bullock
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401.
Yueqin Xu
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401.
David Benson
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401.
Howard M. Branz
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401.
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Abstract

Self-powered “smart” windows utilize an electro-optic transmittance modulator based on electrochromic (EC) thin films that exhibit reversible and controlled changes in optical properties with an applied voltage between 0.7 and 2.0 V. Existing window designs require an external electrical connection, which may be economically unfeasible. This problem is solved by the tandem photovoltaic-electrochromic device, in which a wide-gap amorphous silicon-based alloy photovoltaic device is deposited together with an electrochromic optical transmittance modulator in a monolithic device on a single substrate. In this paper, we discuss our proposed monolithic photovoltaic-electrochromic device.

We also present studies of transparent, wide-gap (1.8 to 2.2 eV) amorphous silicon-carbon thin films and p-i-n devices designed for use in the photovoltaic-electrochromic device. These photovoltaic cells can operate at low current (<1 mA/cm2) because a total injected charge of only 60 μC/cm2 will darken the EC layer to a visible transmission of 5%, but they need a high open-circuit voltage (>1.0 V) and high transparency (≈70%). We present our progress toward these design targetxxss.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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