Dye-sensitized solar cells based on nitrogen-doped TiO2-B nanowire/TiO2 nanoparticle composite photoelectrode

► N-doped TiO2-B NWs are obtained using NH3 as a precursor under middle pressures. ► N-doped NW/NP composite DSSCs have higher η of 7.21% than that of non-doped DSSCs. ► Composite combine the rapid electron transport in NWs and high surface area of NPs. ► Formation of O-Ti-N in the TiO2-B NW increases interfacial charge transfer rate.