Accurate assessment of external quantum
efficiency provides information useful for
understanding where losses in energy
conversion efficiency occur in solar cells. These
systems are typically designed to measure small
areas only, which makes it impossible to
measure the quantum efficiency of monolithically
integrated modules and thus any effects due to
interconnection cannot be assessed. A system
for measuring spectral response has been
designed and recently commissioned at CREST
with a view to making measurements on larger
areas. The external quantum efficiency of solar
cells is calculated based around a series of
narrow-band interference filters and
homogenising optical elements that are able to
provide a large-area, homogeneous,
monochromatic illumination. In this paper the
initial characterisation of the system will be
presented. It is the intention to further improve
the functionality of the system over the coming
year and the planned enhancements will be
discussed in light of their effects on
measurement accuracy, in particular for devices
such as dye cells and multi-junction cells which
have more complicated electro-optical
characteristics than basic silicon wafer cells
