Organic-inorganic hybrid solar cells made from hyperbranched phthalocyanines

Organic-inorganic hybrid solar cells with a cell structure of indium tin oxide/TiO2/TiOx:hyperbranched phthalocyanine/CuSCN/Au (or carbon) have been fabricated by solution based processing using three hyperbranched phthalocyanines (H2PPc, TiOPPc and CuPPc) as light-absorbing materials. These organic-inorganic hybrid solar cells are extremely thin absorber solar cells, which possess p-i-n heterojunctions ("i," an intrinsic absorber layer), as they were confirmed by scanning electron microscopy. With an illuminated area of 1 cm2, a solar cell made from H2PPc achieved conversion efficiency of 0.23% under 1-sun air mass 1.5 global illumination. The lower conversion efficiency for the cell made from CuPPc was likely due to the energy loss in the formation of triplet states with an intersystem crossing time of 0.76 ps.