Patterned FTO electrodes for DSSCs were fabricated by a facile wet etching method. Pattern depth could be controlled by etching time. Most DSSCs with patterned FTO electrodes exhibited both larger open-circuit voltage and photocurrent density. Energy conversion efficiency gradually increased with longer etching time and achieved a highest value when etching time is 240s. An optimum pattern depth was required to acquire best DSSC performance. The improved device performance could be mainly attributed to more dye adsorption, enhanced light harvesting and scattering due to larger amount of TiO₂ nanoparticles filled in the pattern. More contact between TiO₂ nanoparticles and patterned FTO with larger surface area was also an advantage. It was revealed from Nyquist plots that the charge transfer impedance at the TiO₂/dye/electrolyte interface apparently influenced the magnitude of photocurrent density and device performance. Electron transfer became easier and higher performance was thereby obtained when a DSSC had a smaller interfacial impedance. This study has demonstrated obvious improvement in DSSC performance by surface patterning of FTO electrodes. With appropriate etching condition, the highest energy conversion efficiency of 7.71% was achieved, which was around 16 % higher than that of the DSSC with unpatterned FTO electrode.

Date Published: 6 October 2014
PDF: 5 pages
Proc. SPIE 9184, Organic Photovoltaics XV, 918426 (6 October 2014); doi: 10.1117/12.2061963

Published in SPIE Proceedings Vol. 9184:
Organic Photovoltaics XV
Zakya H. Kafafi; Paul A. Lane; Ifor D. W. Samuel, Editor(s)