Highly Efficient Quasi-solid State Flexible Dye-sensitized Solar Cells Using a Compression Method and Light-confined Effect for Preparation of TiO2 Photoelectrodes

A mesoporous nanocrystalline TiO2 film was prepared on a transparent conductive polymer (ITO/PEN, PEN = poly ethylene naphthalene-2, 6-dicarboxylate) through a doctor-blade method and then treated by static mechanical compression for enhancing the particles connection. Effect of TiO2 loading and dye sensitizing condition on the photovoltaic performance were first investigated with N719 sensitizer in combination with TiO2 solidified quasi-solid electrolyte. A solar cell with platinum-coated FTO glass counter electrode and ITO/PEN photoelectrode, prepared by an ethanol based binder-free TiO2 paste composed of a mixture of P25 (21 nm, 25% rutile and 75% anatase) and 100 nm anatase TiO2 particles, yielded highest conversion efficiencies of 6.53% under 1 sun illumination.