High Efficiency of Dye-Sensitized Solar Cells

          We used the high intensity UV-O3 treat TiO₂ layer surface in get rid of carbon contamination completely in the fabrication of N719 dye sensitized solar cell. The efficiency is close to 12% for the first time. We have improved the conversion efficiency of Dye-Sensitized Solar Cells (DSSCs) by using high intensity UV radiation-ozone treatment on nanocrystalline TiO₂ layers after sintering. The UV light sources used had powers of 1,650 W and 500 W. UV-Ozone treatment on nanocrystalline TiO₂ layers was performed for 10 minutes with fixed distance between TiO₂ layers and UV light source of about 3 cm. Experimental results, shown in the table below, indicate that photocurrent and power conversion efficiency of cells increased when using high power intensity 1,650 W and 500 W of UV-ozone treatment on TiO₂ layers. The short circuit current density (J_sc) increased to 25.36 mA/cm² and 22.31 mA/cm², the open circuit voltage (V_oc) to 0.71 V and 0.73 V, the fill factor (FF) to 0.66 and 0.68 and the power conversion efficiency to 11.95 % and 11.16%, respectively. The DSSCs were characterized for absorption dye, chemical structure on nanocrystalline TiO₂ layer and electrochemical properties by UV-Visible spectroscopy, XPS, XRD, contact angle measurement and impedance spectroscopy respectively. This work will be published in Journal of Non-Crystalline Solids 2012.

Figure on the left shows ozone formation by UV activation.
Figure on the right shows the photocurrent-voltage characteristics of DSSCs with UV-O3 treatment
on TiO₂ films;  (Cell A) with power UV 1,650 W, (Cell B) with power UV 500W and (Cell C) without treatment.