Electrospinning of SnO2-TiO2 Nanofiber/Nanorod Composites for Uses as Electron Transport Layers in Flexible Perovskite Solar Cells

Titanium dioxide (TiO2) and tin oxide (SnO2) are the most often employed electron transport layers (ETLs) in perovskite solar cells (PSCs). However, due to its photocatalytic activity, TiO2 can destroy perovskite materials, whereas the disadvantage of SnO2 is its mismatched conduction band between perovskites. Moreover, these ETLs are predominantly utilized as nanoparticles. To overcome their drawbacks, we manufactured composite nanofibers or nanorods of SnO2-TiO2 using electrospinning to enhance the photovoltaic performance of flexible PSCs that are required for flexible electronic devices. SnO2-TiO2 nanofibers or NRs as ETLs promote light harvesting in perovskites, exciton separation, electron extraction and collection, hole blocking, and inhibit perovskite disintegration and defect formation. PSCs containing SnO2-TiO2 NPs have been manufactured. From the J-V characteristics of F-PSCs, it was evidentially found
that the use of SnO2-TiO2 nanofibers improved the power conversion efficiency of the solar cells. The higher Jsc was achieved. This ascribes to the increased electron mobility due to the 1D structure. Moreover, the SnO2-TiO2 composite layer brings better bandgap matching and interface adhesion at the perovskite/FTO interface compared with SnO2 nanoparticles and TiO2 nanofibers. Thus, reduces surface recombination compared with SnO2 NPs and TiO2 nanofibers.