Improvement of dye-sensitized solar cell performance through introducing TiO₂ in acetylene carbon black-graphite composite electrode

Abstract

In this work, we have investigated the performance of acetylene carbon black/graphite (AB/G) composite counter electrodes (CEs) by incorporating TiO2 as a binder in dye-sensitized solar cells (DSSCs). We obtained five types of composite CE films at different weight ratios of 0:1, 1:3, 1:1, 3:1 and 1:0 by adding a constant amount of TiO2 to a mixture of AB/G. The performance of the composite electrodes was assessed by using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopies and photocurrent density–voltage characteristics. The results have shown enhanced DSSC efficiency due to improved charge transfer properties of the CE when adding TiO2. TiO2 enhances the binding of the electrode to the substrate. AB/G/TiO2 composites show superior overall results compared to AB/TiO2 and G/TiO2. Since AB has high catalytic activity and surface area, as the AB content of the composite is increased, the electrochemical properties of the CEs are improved. The DSSC with AB:G (3:1) exhibited the maximum power conversion efficiency (PCE) of 5.9% with the highest fill factor (FF) of 0.55, which are comparable to those DSSCs employing platinum CEs with PCE of 6.2% and FF of 0.67.