Modeling of optical losses in graphene contacted thin film solar cells

For the first time, we model the optical loss of short-circuit current density, Jsc, and conversion efficiency, η, of thin film solar cells made of CdS/CdTe and CIGS/CdS chalcogenide materials having a graphene nanolayer electrode. The model is based on known materials optical constants e.g. refract...

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Veröffentlicht in:Materials letters 2016-02, Vol.164, p.493-497
Hauptverfasser: Houshmand, M., Hossein Zandi, M., Gorji, Nima E.
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Sprache:eng
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Zusammenfassung:For the first time, we model the optical loss of short-circuit current density, Jsc, and conversion efficiency, η, of thin film solar cells made of CdS/CdTe and CIGS/CdS chalcogenide materials having a graphene nanolayer electrode. The model is based on known materials optical constants e.g. refractive index and extinction coefficient reported in literature. Graphene has a superior transmission, conductivity and thermal stability than conventional transparent conductive oxide (TCO) and metallic back contacts. We compare our modeling results with experimental data reported in the literature and re-optimize the thickness of device components. The interface reflections result in ΔJsc=−8.5% whereas absorption in graphene, ZnO, CdS layers (with typical thicknesses) results in ΔJsc=−25% for glass/graphene/ZnO/CdS/CdTe, and about 24% for glass/MO/CIGS/CdS/ZnO/graphene solar cells. CIGS materials with higher bandgap (1.38eV vs. 1.17eV) cause a higher ΔJsc. Graphene/ZnO contacted devices show lower efficiency loss with respect to graphene monolayer without ZnO layer. ZnO has a middle value of optical properties which balances the light refraction at the interface of graphene and chalcogenide materials. •For the first time, we model the optical loss of thin film photovoltaics with a nanolayer electrode.•Nanolayers significantly reduce the reflection/absorption loss and enhance the Jsc.•Graphene is a promising material to be replaced with conventional TCOs or metallic contacts.
ISSN:0167-577X
1873-4979
DOI:10.1016/j.matlet.2015.11.050