Dissymmetric interface design of SnO2/TiO2 side-by-side bi-component nanofibers as photoanodes for dye sensitized solar cells: Facilitated electron transport and enhanced carrier separation

SnO 2 /TiO 2 type II heterojunctions are often introduced to enhance the separation efficiency of photogenerated carriers in photoelectrochemical electrodes, while most of these heterojunctions are of core–shell structure, which often limits the synergistic effect from the two components. In this work, dissymmetric SnO 2 /TiO 2 side-by-side bi-component nanofibers (SBNFs) with tunable composition ratios have been prepared by a novel needleless electrospinning technique with two V-shape connected conductive channels (V-channel electrospinning). Results show that this V-channel electrospinning technique is more stable, controllable and tunable for the large-scale preparation of SBNF materials compared to the traditional electrospinning using two side-by-side metal needles. And these SnO 2 /TiO 2 SBNFs are dissymmetric and comprised of a tiny SnO 2 NF (tunable diameter within 20–80 nm) and a Sn-doped TiO 2 NF (diameter of ~ 250 nm) with a side-by-side structure. Moreover, the dye-sensitized solar cells (DSSCs) based these dissymmetric SnO 2 /TiO 2 SBNFs show the maximum power conversion efficiency (PCE) of 8.3%, which is 2.59 times that of the ones based on the TiO 2 NFs. Series of analyses indicate that the enhancements in PCE could mainly be due to the improved electron transport via SnO 2 NFs and the enhanced carrier separation via dissymmetric SnO 2 /TiO 2 heterojunction interface. This research will give some new insight in the preparation of SBNFs for high-performance photoelectrochemical devices.