Silicon solar cells
are operating close to the theoretical maximum
efficiency limit. To increase their efficiency beyond this limit,
it is necessary to decrease energy losses occurring for high-energy
photons. A sensitizing layer of singlet-fission material can in principle
double the current generated by high-energy photons, and significantly
reduce energy losses from high-energy photons within the solar cell.
Here, we construct a model of such a solar cell, using Si(111) surfaces
and tetracene. To increase the energy transfer between the two layers,
a series of tetracene derivatives was synthesized, and the molecules
were covalently attached onto the silicon surface as a seed layer.
Using X-ray diffraction, a shift in crystal structure and ordering
of the tetracene close to the seed layer can be observed. Unfortunately,
the effect on the energy transfer was limited, showing a need for
further investigations into the effect of the seed layer.