Optimization of dye adsorption time and film thickness for efficient ZnO dye-sensitized solar cells with high at-rest stability

Abstract

Photoelectrodes for dye-sensitized solar cells were fabricated using commercially available zinc oxide (ZnO) nanoparticles and sensitized with the dye N719. This study systematically investigates the effects of two fabrication factors: the ZnO film thickness and the dye adsorption time. Results show that these two fabrication factors must be optimized simultaneously to obtain efficient ZnO/N719-based cells. Different film thicknesses require different dye adsorption times for optimal cell performance. This is because a prolonged dye adsorption time leads to a significant deterioration in cell performance. This is contrary to what is normally observed for titanium dioxide-based cells. The highest overall power conversion efficiency obtained in this study was 5.61%, which was achieved by 26-μm-thick photoelectrodes sensitized in a dye solution for 2 h. In addition, the best-performing cell demonstrated remarkable at-rest stability despite the use of a liquid electrolyte. Approximately 70% of the initial efficiency remained after more than 1 year of room-temperature storage in the dark. To better understand how dye adsorption time affects electron transport properties, this study also investigated cells based on 26-μm-thick films using electrochemical impedance spectroscopy (EIS). The EIS results show good agreement with the measured device performance parameters.

A Simple Approach on Synthesis of TiO2 Nanoparticles and its Application in dye Sensitized Solar Cells

“…6(a and b) respectively. This may be inferred that Jsc is considered as an efficiency-determining parameter since the film thicknesses have shown stronger effect on Jsc than on the other photovoltaic parameters [28][29][30]. Finally, Fig.…”

Thermal treatment optimization of ZnO nanoparticles-photoelectrodes for high photovoltaic performance of dye-sensitized solar cells

“…For example, suitable electrolyte and dye materials need to be developed, and the fabrication parameters and design of the nanostructure need to be optimized, which is essential for maximizing the energy conversion efficiency (Kakiuchi et al, 2006;Rao and Dutta, 2008). The effect of the morphology, thickness and presence of aggregates of nanostructured ZnO films on the efficiency of dye-sensitized solar cells was studied by Giannouli and Spiliopoulou (2012) while Chang et al (2012) reported the optimization of dye adsorption time and film thickness for efficient ZnO dye-sensitized solar cells with high at-rest stability.…”

Efficiency Investigations of Organic/Inorganic Hybrid ZnO Nanoparticles Based Dye-Sensitized Solar Cells

“…The thickness of the photoanodes (in m) for the current ZnO based DSSCs showed a significant increase in the photonto-electric power conversion efficiency. The thickness of the photoanode layers was calculated to be 10.57 m, 16.11 m, and 25.40 m for samples A, B, and C, respectively, by using 3 micromolars per centimeter square and the calculations were performed as per the method given in the literature [35][36][37]. The coating of another material over the parent ZnO leads to increase in the thickness of the coating.…”