Hierarchically structured TiO 2 (HS-TiO 2) was prepared on a flexible ITO-PEN (polyethylene naphthalate) substrate via electrospray deposition using a commercially available TiO 2 nanocrystalline powder in order to fabricate flexible DSSCs under low-temperature (<150 °C) conditions. The cell efficiency increased when using flexible ITO-PEN substrates post-treated by either a mechanical compression treatment or a chemical sintering treatment using titanium n-tetrabutoxide (TTB). The mechanical compression treatment reduced the surface area and porosity of the HS-TiO 2; however, this treatment improved the interparticle connectivity and physical adhesion between the HS-TiO 2 and ITO-PEN substrate, which increased the photocurrent density of the as-pressed HS-TiO 2 cells. The electron diffusion coefficients of the as-pressed HS-TiO 2 improved upon compression treatment, whereas the recombination lifetimes remained unchanged. An additional chemical sintering post-treatment involving TTB was tested for its effects on DSSC efficiency. The freshly coated TiO 2 submitted to TTB hydrolysis in water at 100 °C yielded an anatase phase. TTB treatment of the HS-TiO 2 cell after compression treatment yielded faster electron diffusion, providing an efficiency of 5.57% under 100 mW cm -2, AM 1.5 global illumination.
All Science Journal Classification (ASJC) codes
- Materials Science(all)