Charge transport and recombination in dye-sensitized solar cells based on hybrid films of TiO2 particles/TiO2 nanotubes

► The electron lifetime increases with increasing the nanotube concentration. ► The electron transport time is shortest at 10 wt% TiO2 nanotubes. ► The electron collection efficiency achieves maxima at 10 wt% nanotubes. ► The energy conversion efficiency obtains the highest value at 10 wt% nanotubes.