Effects of Nanocrystalline Porous TiO2 Films on Interface Adsorption of Phthalocyanines and Polymer Electrolytes in Dye-Sensitized Solar Cells

Summary: We have synthesized three kinds of titanylphthalocyanines with different crystal structures (TiOPcs; PcT2000R, PcT3000R, and PcT1100S) and analyzed their crystal structure by X-ray Diffraction (XRD), Fourier transfer IR (FT-IR) spectroscopy, and Transmission Electron Microscope (TEM). From experimental results, we have confirmed that PcT2000R was estimated to be alpha-form; PcT3000R was beta-form, and PcT1100S was gamma-form. Quasi-solid state dye-sensitized solar cell (DSSC) devices were prepared with a polymer electrolyte using TiOPcs as a co-adsorbent. The DSSC device using TiOPc has higher power conversion efficiency than without TiOPc, due to decrease of electron transfer distance by the interface adsorption between TiO₂ film and polymer electrolyte. Also, we have studied the effects of the crystal structures of TiOPcs on the property of polymer electrolyte and the performance of the DSSC device. The best result on power conversion efficiency was 7.13% in DSSC device using PcT3000R having its highest stability. The open-circuit voltage (V_oc) was 0.69 V, the short-circuit current density (J_sc) was 20.02 mA/cm², and the Fill Factor (FF) was 0.52. the addition of TiOPc as co-adsorbent is useful for improve to the performances of DSSC devices such as V_oc, J_sc, and power conversion efficiency.