A Combined Effect of Plasmon Energy Transfer and Recombination Barrier in a Novel TiO2/MgO/Ag Working Electrode for Dye-Sensitized Solar Cells

Chanu Photiphitak,Pennapa Muthitamongkol,Chanchana Thanachayanont,Pattana Rakkwamsuk

doi:10.1155/2015/795138

Abstract

Novel TiO2/MgO/Ag composite electrodes were applied as working electrodes of dye-sensitized solar cells (DSSCs). The TiO2/MgO/Ag composite films were prepared by dip coating method for MgO thin films and photoreduction method for Ag nanoparticles. The MgO film thicknesses and the Ag nanoparticle sizes were in ranges of 0.08–0.46 nm and 4.4–38.6 nm, respectively. The TiO2/MgO/Ag composite films were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The TiO2/MgO/Ag composite electrodes were sensitized by immersing in a 0.3 mM of N719 dye solution and fabricated for conventional DSSCs.J-Vcharacteristics of the TiO2/MgO/Ag DSSCs showed that the MgO film thickness of 0.1 nm and the Ag nanoparticle size of 4.4 nm resulted in maximum short circuit current density and efficiency of 8.6 mA/cm2and 5.2%, respectively. Electrochemical Impedance Spectroscopy showed that such values of short circuit current density and efficiency were optimal values obtained from plasmon energy transfer by 4.4 nm Ag nanoparticles and recombination barrier by the ultrathin MgO film.

Highlights

For more than 20 years, the first dye-sensitized solar cell (DSSC) has been published by O’Regan and Gratzel [1]
We found that the Electrochemical impedance spectra (EIS) of the DSSCs with the TiO2/MgO (0.10 nm)/Ag (4.4 nm) composite electrode have the smallest curve of R2
The TiO2/MgO/Ag composite electrode was prepared with the MgO thin film and the Ag nanoparticles by dipping and photoreduction method, respectively

Summary

Introduction

For more than 20 years, the first dye-sensitized solar cell (DSSC) has been published by O’Regan and Gratzel [1]. The DSSCs have been extensively studied because of their high performance, simple fabrication processes, low-cost materials, and manufacturing processes. The DSSCs consist of transparent conducting oxide (TCO) coated glass, TiO2 photoelectrode, Ru complex photosensitizer such as N719 dye molecules, redox electrolyte such as I−/I3− (iodide/triiodide), and Pt counter electrode [2]. High performance dyesensitized solar cells require the nanocrystalline TiO2 electrode to have a large surface area, high crystallinity without cracks, and good electrical contact with the conducting glass substrate so that a high amount of dye molecules can be adsorbed and the electrons can be quickly transferred [3]. Main reasons are charge recombination loss arising at the semiconductor/dye/electrolyte interface and low dye absorption towards the infrared region

Methods

Results

Conclusion