TiO₂/CNTs Dye Sensitized Solar Cell

Dye-sensitized solar cell(DSSC) has attracted more and more attentions, because of its low costs, simple manufacturering process and high photoelectric conversion efficiency. Photoanode and counter electrode are the key parts of the DSSC, the quality of their performance would decide the photoelectric conversion efficiency. In this paper, we focusd on the study of photoanode and counter electrode.Fisrtly, we investigated the surfactants effect on the TiO2 film dispersity. The porous structure and morphology of the TiO2 film which is benificial for increasing of dye adsorption, facilitating diffusion of electrolytes and enhancing the transport of electrons has been prepared by adding different kinds of surfactants. The prepared DSSC got a photoelectric conversion efficiency of 2.86%, which shows higher efficiency compared with the pure commercial TiO2 slurry(2.69%).Secondly, the effect of Ti O2 slurry incorporated by Carbon nanotube(CNT) was studied systematically. The TiO2 slurry are incorporating with different concentration of CNTs to form TiO2/CNTs composite film. The results showed that: the short current(Jsc) increased from 7.36mA/cm2 to 9.02mA/cm2 with the increase of CNTs amount from 0 to 0.05 wt. %. Accordingly, the photoelectric conversion efficiency of DSSC based on CNTs-incorporated TiO2(0.05 wt.% CNTs) increased to 3.51%, 23% higher than that of pristine TiO2 DSSC(2.86 %).Thirdly, to get high photoelectric conversion efficiency, the influence of different concentrations of TiCl4 post-treatment on commercial TiO2 slurry is investigated. We foud that: the Jsc increases from 7.83 mA/cm2 to 12.51 mA/cm2 with the increase of TiCl4 concentration from 0 to 0.1mol/L. When the concentration of TiCl4 is 0.1mol/L, the DSSSC pretented photoelectric conversion efficiency of 3.74%, while the pristine TiO2 DSSC is only 2.69%.Then, we investigated the effect of functionalized CNTs on the performance of DSSC. After the acid treatment, the CNTs were grafted functional groups(-COOH) and then mixed with TiO2 slurry, formed TiO2/CNTs composite film, followed treatment by the 0.1mol/L TiCl4. The Jsc increases from 10.38mA/cm2 to 14.74mA/cm2 and the photoelectric conversion efficiency from 4.32% to 6.23% with the increase of CNTs amount from 0 to 0.06 wt. %. Continuing to increase the amount of CNTs again, the photoelectric conversion efficiency and the short current has fallen obvious.Finally, we fabricated the Pt counter by evaporation plating, and get the photoelectric conversion efficiency of 2.20%, short current of 7.87 mA/cm2, open voltage of 0.62 V. Then growing CNTs at the surface of Pt by MWCVD, fabricating the Pt/CNTs composite film, we found that: the photoelectric conversion efficiency increased from 2.20% to 2.68%, the short current increased from 7.87 mA/cm2 to 10.33 mA/cm2.