Very wide-bandgap nanostructured metal oxide materials for perovskite solar cells

Very wide-bandgap undoped and Y$_2$O$_3$-doped ZrO$_2$ nanoparticles were synthetized and their structural, optical, morphological and energy characteristics were investigated. It was found that the bandgap value in ZrO$_2$ decreases with Y$_2$O$_3$ doping. The developed materials were used for fabrication of nanostructured photoelectrodes for perovskite solar cells (PSCs) with the architecture of glass/FTO/ZrO$_2$-Y$_2$O$_3$/CH$_3$NH$_3$PbI$_3$/spiro-MeOTAD/Au. The power conversion efficiency in the PSCs based on ZrO$_2$-Y$_2$O$_3$ photoelectrodes was significantly higher than that for undoped ZrO$_2$ photoelectrodes. We have found that nanostructured layers, based on very wide-bandgap materials could efficiently transfer the injected electrons via a hopping transport mechanism.