An attempt is made to understand, quantify, and reduce the reflectance and photocurrent loss in CdTe solar cells. Model calculations
are performed to determine the optimum thicknesses of CdS and SnO2 films and anti-reflection (AR) coating on glass that can minimize the reflectance and enhance the performance of CdTe/CdS/SnO2/glass solar cells. Photocurrent loss due to absorption in CdS films is
... [Show full abstract] also calculated as a function of CdS thickness. It
was found that the current loss due to reflectance ando absorption is more sensitive to the CdS film when its thickness falls
below 1500Å. Model calculations show that reducing the CdS thickness from 1500 to 600Å increases short-circuit current density
( Jsc) by 3 mA/cm2 because of reduced reflectance as well as absorption. Further decrease in CdS thickness below 600Å increases reflectance
but results in higher Jsc, because current gain due to reduced absorption in thin CdS offsets the current loss due to higher reflectance. Model calculations
also indicate that Jsc is not sensitive to SnO2 thickness above 4000Å. Finally, an optimum thickness for single layer MgF2 AR coating on glass was calculated to be 1100Å, which should provide an additional increase of 0.7 mA/cm2 in Jsc. Some of these results are also experimentally validated in this paper.
