  The economic value of a photovoltaic installation depends upon both its
lifetime and power conversion efficiency. Progress towards the latter includes
mechanisms to circumvent the Shockley- Queisser limit, such as tandem designs
and multiple exciton generation (MEG). Here we explain how both silicon tandem
and MEG enhanced silicon cell architectures result in lower cell operating
temperatures, increasing the device lifetime compared to standard c-Si cells.
Also demonstrated are further advantages from MEG enhanced silicon cells: (i)
the device architecture can completely circumvent the need for
current-matching; and (ii) upon degradation, tetracene, a candidate singlet
fission (a form of MEG) material, is transparent to the solar spectrum. The
combination of (i) and (ii) mean that the primary silicon device will continue
to operate with reasonable efficiency even if the singlet fission layer
degrades. The lifespan advantages of singlet fission enhanced silicon cells,
from a module perspective, are compared favorably alongside the highly regarded
perovskite/silicon tandem and conventional c-Si modules.
