We have investigated the inkjet-printing of TiO 2 films for the fabrication of dye-sensitized solar cells (DSSCs). In order to realize the uniform printing of TiO 2 films, the co-solvent ink was designed by introducing a drying agent to the ink. This co-solvent ink induces a circulating flow within ink droplets and leads to the uniform lines and films by inkjet. A theoretical model was used to predict the optimal ink-droplet pitches for the inkjet-printing of uniform lines. This model also contributes to the formation of uniform films since they are filled with the inkjet-printed lines. The inkjet-printed TiO 2 films were used as photoelectrodes for dye-sensitized solar cells. The thickness of the inkjet-printed TiO 2 films was varied to optimize the photovoltaic performance of DSSCs. Since no organic additives were introduced into the TiO 2 inks, the feasibility of reducing the annealing temperature for TiO 2 photoelectrodes was investigated. This study may suggest an opportunity to fabricate DSSCs at low temperature.

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We have investigated the UV-assisted chemical (UV-Chemical) sintering of inkjet-printed TiO 2 photoelectrode films for the fabrication of low temperature flexible dye-sensitized solar cells (DSSCs). A titanium organic compound as a chemical sintering source was introduced to an ink where TiO 2 nanoparticles were dispersed. The formulated ink was printed by inkjet to prepare TiO 2 photoelectrodes for DSSCs. The UV irradiation on the inkjet-printed photoelectrode led to the photodecomposition of the titanium organic compound at 150 • C, resulting in the formation of new TiO 2 among the TiO 2 nanoparticles in the photoelectrode. The newly formed TiO 2 enhanced the connectivity among TiO 2 nanoparticles in the photoelectrode. The microstructure of TiO 2 photoelectrode was investigated both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in order to verify the effect of the UV-Chemical sintering on TiO 2 interparticle connectivity. The photovoltaic performance of DSSCs with the UV-Chemical sintered TiO 2 photoelectrodes was characterized by incident photon-to-current conversion efficiency (IPCE) and electrochemical impedance analysis. Based on this learning, flexible DSSC was also fabricated on the plastic substrate. This study suggests that UV-assisted chemical sintering offers a feasible opportunity to fabricate low-temperature flexible DSSC.