Effect of compressed TiO2 nanoparticle thin film thickness on the performance of dye-sensitized solar cells
1 Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan
2 Department of Materials Science and Engineering, National Cheng Kung University, Tainan City 701, Taiwan
Nanoscale Research Letters 2013, 8:459 doi:10.1186/1556-276X-8-459Published: 5 November 2013
In this study, dye-sensitized solar cells (DSSCs) were fabricated using nanocrystalline titanium dioxide (TiO2) nanoparticles as photoanode. Photoanode thin films were prepared by doctor blading method with 420 kg/cm2 of mechanical compression process and heat treatment in the air at 500°C for 30 min. The optimal thickness of the TiO2 NP photoanode is 26.6 μm with an efficiency of 9.01% under AM 1.5G illumination at 100 mW/cm2. The efficiency is around two times higher than that of conventional DSSCs with an uncompressed photoanode. The open-circuit voltage of DSSCs decreases as the thickness increases. One DSSC (sample D) has the highest conversion efficiency while it has the maximum short-circuit current density. The results indicate that the short-circuit current density is a compromise between two conflict factors: enlargement of the surface area by increasing photoanode thickness and extension of the electron diffusion length to the electrode as the thickness increases.