Effect of counter electrode, thickness and sintering temperature of TiO2 electrode and TBP addition in electrolyte on photovoltaic performance of dye sensitized solar cell using pyronine G (PYR) dye

Dye sensitized solar cells (DSSCs) assembled with nano-crystalline TiO2 adsorbed with pyronine G (PYR) dye as photoanode and polar solvent-treated poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) coating on a conductive glass (fluorine-doped thin oxide, FTO), as a counter electrode were studied. It was found that the DSSC using carbon black (0.2 wt%) modified DMSO-PEDOT:PSS conductive coating as a counter electrode resulted highest power conversion efficiency. This is attributed to the role of DMSO in enhancing the conductivity of a PEDOT:PSS film and carbon black plays a vital role in increasing the catalytic activity of the film due to its larger surface area. The solar cell performance was studied as a function of sintering temperature and thickness of TiO2 layer, dye sensitization time of TiO2 electrode and electrolyte composition. The DSSCs consist of TiO2 electrode sintered at a temperature of 450 °C shows higher photocurrent attributed to the formation of higher crystalline film. This enhancement in the interconnection between particles results a swift diffusion of electrolyte and good transportation of electrons in the film. All types of DSSC possess the same dependence of performance on the photoanode thickness, i.e. the efficiency increases with the anode thickness to a maximum value, and then decreases slightly when the thickness of photoanode increases further. The effect of pyridine derivative addition in electrolyte on the performance of photovoltaic parameters of DSSCs has also been investigated. A reduced interface defect density and a resulting reduction of charge carrier recombination were found to be the main mechanism for an increased open circuit voltage of DSSCs with TBP addition in the electrolyte. The negative shift of conduction band edge of TiO2 after the addition of TBP in electrolyte was also to be a factor in improving the open circuit voltage. The over all power conversion efficiency of the DSSCs with TBP in the electrolyte is about 5.24%.