Low cost, platinum free counter electrode with reduced graphene oxide and polyaniline embedded SnO2 for efficient dye sensitized solar cells

Abstract

A composite consisting of Reduced Graphene Oxide (RGO), Tin Oxide (SnO2) nanoparticles and Polyaniline (PANI) conducting polymer was studied as a potential counter electrode material for Dye Sensitized Solar Cells (DSSCs). This RGO/SnO2/PANI composite CE was fabricated by spray method and used as an alternative to Platinum (Pt) counter electrode (CE). In the fabrication of RGO/SnO2/PANI composite CEs, several optimizations were carried out to obtain the optimum RGO sintering temperature and the optimum amounts of RGO, SnO2 and PANI. The photovoltaic performance of the DSSCs based on the newly prepared CEs was studied by using I-V measurements. The efficiency of the DSSC with the CE with optimized RGO/SnO2/PANI composition having 9.8 μm thickness was 7.92% under the 100 mW cm−2 (1.5AM) light illumination. After the TiCl4 treated TiO2 photoanode was used, the maximum power conversion efficiency of the DSSC based on the RGO/SnO2/PANI composite CE was increased to 8.68%, which corresponds to an impressive 94% of the efficiency of 9.22% obtained for the control DSSC made with Pt CE and TiCl4 treated photoanode measured under same light illumination. These composite CEs were characterized by X-ray diffraction, Raman spectra, FTIR spectra, SEM and TEM. Cyclic voltammetry (CV) analysis showed the excellent electro-catalytic activity of the composite CE. With high energy conversion efficiency and improved charge-transfer process of DSSCs in combination with simple preparation and relatively low-cost technique, the RGO/SnO2/PANI composite electrode demonstrates the beneficial use of this novel composite material as CEs in DSSCs.