AVS 57th International Symposium & Exhibition
    Energy Frontiers Topical Conference Thursday Sessions
       Session EN+NS-ThM

Paper EN+NS-ThM4
The Influence of Acid Treatment of TiO2 Film Prepared by FFCVD on the Performance of Dye-Sensitized Solar Cell

Thursday, October 21, 2010, 9:00 am, Room Mesilla

Session: Nanostructures for Energy Conversion & Storage II
Presenter: B.R. Chen, National Dong Hwa University, Taiwan, Republic of China
Authors: B.R. Chen, National Dong Hwa University, Taiwan, Republic of China
Y.J. Chen, National Dong Hwa University, Taiwan, Republic of China
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In this study, we use the acid treatment to enhance the dye-sensitized solar cell (DSSC) efficiency from 4.58% to 5.87%. Comparing with the untreated films, the photocurrent and efficiency both largely increase ~28%. We also found that the use of acetic acid, as well as hydrochloric acid, can easily enhance the performance of DSSCs. The untreated film was prepared using a one-step method by the flat-flame chemical vapor deposition (FFCVD) system which deposits the nanoporous TiO2 film directly as working electrode used in the DSSC. The TiO2 film was grown on ITO substrate at the temperature of 400℃ and the pressure of 20 torr. The efficiency of DSSC using as-synthesized TiO2 electrode approaches 4.58% with the film thickness about 11~13 mm with proper tuning of carrier gas flow rate in the TiO2 deposition process. We know that the DSSCs with best efficiency about 11% were prepared exclusively by hydrothermal method. The efficiency we have is among the highest for DSSCs prepared through non-hydrothermal process. The influence of acid treatment increase conversion efficiency was largely attributed to the short circuit current increase. In previous studies, some group improved the acid treatment to make the dye absorption increase effectively. However, most of them performed the treatment during hydrothermal process for the powder synthesis, which cannot be incorporated with the direct film preparation process. Therefore, we take the dipping method to treat our nanoporous TiO2 film, and try to determine if the treatment can enhance the dye absorption as well. The crystalline quality and morphologies of surface modified TiO2 electrodes were characterized by using XRD and FESEM. FT-IR and XPS were used to perform the surface characterization. The dye absorption of the DSSCs was also characterizes by UV-vis spectrophotometer. The efficiency of DSSCs using these working electrodes were measured under AM 1.5G 100 mW/cm2 by Keithley 2400 sourcemeter. The optimized cell efficiency is 5.87% with the short-circuit photocurrent density of 14.50 mA/cm2 and open-circuit voltage of 0.60 V at 0.1M hydrochloric acid solution and half-an-hour soaking.