One-Step Electrophoretic Deposition of Magnesium Oxide-Coated Tin Oxide Film and Its Application to Flexible Dye Sensitized Solar Cells

Abstract

Magnesium oxide-coated tin oxide (MgO-coated SnO2) powder consisted of aggregates was prepared by a facile method. The MgO-coated SnO2 powder was characterized by X-ray diffractometer, field emission scanning electron microscope, energy dispersive spectroscopy and Raman spectroscopy. The aggregates were composed of nanoparticles, which promised a large surface area of 74.27 m2 g−1. MgO-coated SnO2 porous films utilized in dye-sensitized solar cells (DSSCs) were prepared using one-step electrophoretic deposition (EPD) method. The as-deposited films showed no cracks when the film thickness was 49.9 μm. The deposited films are hydrolysed at 413 K and irradiated under UV light. The post-treated MgO/SnO2 films are used as flexible photoanodes in dye-sensitized solar cells (DSSCs). Electrochemical impedance spectroscopy (EIS) is employed to quantify the electron lifetime (τe) of the MgO/SnO2 films. The amount of MgO coating and film thickness are optimized to achieve high energy conversion efficiency. The optimized MgO/SnO2 photoanodes based on transparent conductive glass substrates show an excellent photovoltaic response, with overall power conversion efficiency reaching 5.48% under AM 1.5 G illumination (100 mW cm−2), having a short circuit current density, open circuit voltage, and fill factor of 11.48 mA cm−2, 0.656 V and 0.73, respectively. All-plastic DSSCs are also assembled, which show a light-to-electricity conversion efficiency of 4.01%.