flexible dye-sensitized solar cell, free standing film, TiO2 nanowires, lift-off/transfer technique
A free-standing TiO2 nanowire thin film was prepared using the doctor-blade method. The film is composed of big and small nanowires on each side. The big nanowires have the functions of weakening adhesion to its original substrate, supporting the film after lift-off, and acting as a scattering layer in the final solar cells, whereas the small nanowires provide large surface area for dye loading and good adhesion to the flexible substrate for photoelectron collection. A high efficiency of 5.47% was obtained for flexible dye-sensitized solar cells fabricated by transferring the nanowire films onto ITO–PEN substrates. The mechanically stable and sturdy film have other applications area such as water splitting, photo catalytsis, etc. In addition, modifications can be made to the film to strengthen / weaken its adhesion to the substrate, allowing for various applications.