From our simulation it is originated that, the efficiency of
solar cell increases with the increase of band-gap of the
absorber layer. As the band-gap of CIGS absorber layer varied
from 1.02 to 1.5eV, the solar cell efficiency increased from
13.99 to 24.24%. The open-circuit voltage (Voc) is also
increased from 0.53 to 1.40V as the recombination current
falls. It is mainly depends on the saturation current 10, Further
increase in CIGS band-gap has no significant effect on these
parameters. Again, it has very little effect on short-circuit
current density (Jsc).