Mid-infrared emissivity of crystalline silicon solar cells

Riverola, A., Mellor, A., Alonso Alvarez, D., Ferre Llin, L., Guarracino, I., Markides, C.N., Paul, D.J. , Chemisana, D. and Ekins-Daukes, N. (2018) Mid-infrared emissivity of crystalline silicon solar cells. Solar Energy Materials and Solar Cells, 174, pp. 607-615. (doi:10.1016/j.solmat.2017.10.002)

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The thermal emissivity of crystalline silicon photovoltaic (PV) solar cells plays a role in determining the operating temperature of a solar cell. To elucidate the physical origin of thermal emissivity, we have made an experimental measurement of the full radiative spectrum of the crystalline silicon (c-Si) solar cell, which includes both absorption in the ultraviolet to near-infrared range and emission in the mid-infrared. Using optical modelling, we have identified the origin of radiative emissivity in both encapsulated and unencapsulated solar cells. We find that both encapsulated and unencapsulated c-Si solar cells are good radiative emitters but achieve this through different effects. The emissivity of an unencapsulated c-Si solar cell is determined to be 75% in the MIR range, and is dominated by free-carrier emission in the highly doped emitter and back surface field layers; both effects are greatly augmented through the enhanced optical outcoupling arising from the front surface texture. An encapsulated glass-covered cell has an average emissivity around 90% on the MIR, and dips to 70% at 10 µm and is dominated by the emissivity of the cover glass. These findings serve to illustrate the opportunity for optimising the emissivity of c-Si based collectors, either in conventional c-Si PV modules where high emissivity and low-temperature operation is desirable, or in hybrid PV-thermal collectors where low emissivity enables a higher thermal output to be achieved.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Ferre Llin, Dr Lourdes and Paul, Professor Douglas
Authors: Riverola, A., Mellor, A., Alonso Alvarez, D., Ferre Llin, L., Guarracino, I., Markides, C.N., Paul, D.J., Chemisana, D., and Ekins-Daukes, N.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Solar Energy Materials and Solar Cells
ISSN (Online):1879-3398
Published Online:13 October 2017
Copyright Holders:Copyright © 2017 Elsevier
First Published:First published in Solar Energy Materials and Solar Cells 174:607-615
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
688481Plasmonic PhotovoltaicsDouglas PaulEngineering and Physical Sciences Research Council (EPSRC)EP/M025012/1ENG - ENGINEERING ELECTRONICS & NANO ENG