Improvement of photovoltaic efficiency of dye-sensitized solar cell by introducing highly transparent nanoporous TiO2...

13 nm-sized highly-dispersible TiO2 nanoparticle was synthesized by solvothermal reaction of titanium isopropoxide in a basic condition with tetrabutylammonium hydroxide (TBAH). The prepared TiO2 nanoparticle was applied to fabrication of the transparent nanoporous TiO2 layer with 1.2 microm-thickness. By introducing this buffer layer between FTO and main TiO2 layer in the dye-sensitized solar cell (DSSC), the photovoltaic conversion efficiency was improved from 5.92% to 7.13%. Due to the excellent antireflective role of nanoporous TiO2 buffer layer, the transmittance of FTO glass was increased by 9.2%, and this seemed to be one of the major factors in enhancing photovoltaic conversion efficiency. Moreover, the presence of nanoporous TiO2 buffer layer induces excellent adhesion between FTO and main TiO2 layer, as well as it suppresses the back reaction by blocking direct contact between I3- and FTO electrode.