deletions | additions       diff --git a/Background_CdTe_photovoltaics_PV_is__.md b/Background_CdTe_photovoltaics_PV_is__.md  index 137419c..eeddc47 100644  --- a/Background_CdTe_photovoltaics_PV_is__.md  +++ b/Background_CdTe_photovoltaics_PV_is__.md 
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This paper discusses the optical and electrical factors that reduce the efficiency of a single junction CdTe PV below the SQ limit and provides recommendations on closing this 9.0% gap. We use the index \( \zeta_{SQ} = \frac{ \zeta_{real} }{ SQ_{limit} } \) \cite{Vossier_2015}, efficiency  relative to its own theoretical SQ limit as a measure of this gap.  First Solar CdTe research grade PVs have a value of \( \zeta_{SQ}=0.667 \). This number is relevant when comparing to similar thin film PV such as such as GaAs (\(\zeta_{SQ}= \( ( \zeta_{SQ}=  \frac{28.8}{33.1} \approx 0.87 \))\cite{Yablonovitch_2012}. ) \) \cite{Yablonovitch_2012}.  Even more when we consider that commercial high volume PV modules have \( \zeta_{SQ}=\frac{17.0}{32.2}\approx 0.52 \)\cite{Sinha_2013}.