Group IV Oxides for Perovskite Solar Cells

Nanostructured Group IV oxides (ZrO2 and HfO2) have been synthesized and their structural, optical, and energy parameters have been studied. The obtained nanopowders have been used to fabricate nanostructured thin-film photoelectrodes for perovskite solar cells (PSCs). FTO/cTiO2/HfO2/CH3NH3PbI3/Spiro-MeOTAD/Au cell architecture has been developed. Photovoltaic characteristics and photoconversion efficiency for PSCs based on mesoscopic hafnium and zirconium oxides have been compared to the analogous characteristics for known titania-based PSCs. It has been demonstrated that the differences in the photovoltaic characteristics of PSCs are due to the morphology of the mesoporous HfO2 and ZrO2 layers, as well as to the specific features of charge transfer and accumulation at the perovskite/photoelectrode interface. The results obtained indicate good prospects for the application of nanostructured Group IV oxide materials with Eg > 5 eV as photoelectrodes for PSCs. Charge hopping mechanism in very wide bandgap photoelectrodes and its advantages for the development of high-efficiency PSCs is discussed.