Transparent Electrical Contacts for use in Semi-Transparent Upconverter Perovskite Solar Cells

Upconversion materials integrated into semitransparent perovskite solar cells show tremendous potential in
exceeding the single-junction Shockley-Queisser limit of 33% power conversion efficiency (PCE). In order
for light to reach the upconversion material and be converted into usable wavelengths, highly transparent
and conductive top electrical contacts are needed to replace conventional top contacts. Ultrathin metals that
are ideal for transparent contacts such as gold (Au) have a high surface energy, so seed layers between the
contact and the hole transport layer are also necessary to promote a continuous surface. In this thesis, I test
multiple ultrathin top contacts at various thicknesses for use in triple cation lead halide perovskites. These top
electrical contacts are optimized for compatibility with the triplet-triplet annihilation upconversion materials
used in the Congreve Lab. The primary top contacts tested are MoO3/Au/MoO3 and chromium (Cr) as a
seed layer to Au. A champion efficiency of of 15.3% for the ultrathin contact on a semitransparent perovskite
device is achieved, compared to 17.1% for an opaque contact on a perovskite device of the same composition.