Influence of TiCl 4 treatment on performance of dye-sensitized solar cell assembled with nano-TiO 2 coating deposited by vacuum cold spraying

Abstract

Titanium tetrachloride (TiCl 4) treatment was employed to TiO 2 coating deposited on fluoride-doped tin oxide (FTO) conducting glass and indium oxide doped tin oxide (ITO) conducting glass, respectively. The nano-crystalline TiO 2 coating was deposited using a composite powder composed of polyethylene glycol (PEG) and 25 nm TiO 2 particles by vacuum cold spraying (VCS) process. A commercial N-719 dye was used to adsorb on the surface of TiO 2 coating to prepare TiO 2 electrode, which was applied to assemble dye-sensitized solar cell (DSC). The cell performance was measured under simulated solar light at an intensity of 100 m W·cm −2. Results show that with an FTO substrate the DSC composed of a VCS TiO 2 electrode untreated by TiCl 4 gives a short-circuit current density of 13.1 mA·cm −2 and an open circuit voltage of 0.60 V corresponding to an overall conversion efficiency of 4.4%. It is found that after TiCl 4 treatment to the VCS TiO 2 electrode with an FTO substrate, the short circuit current density of the cell increases by 31%, the open-circuit voltage increases by 60 mV and a higher conversion yield of 6.5% was obtained. However, when an ITO substrate is used to deposit TiO 2 coating by VCS, after TiCl 4 treatment, the conversion efficiency of the assembled cell reduces slightly due to corrosion of the conducting layer on the ITO glass by TiCl 4.