Improved performance of dye-sensitized solar cells upon sintering of a PEDOT cathode at various temperatures

Poly(3,4-ethylenedioxythiophene) (PEDOT) thin films have attracted considerable attention as cathodes for dye-sensitized solar cells (DSSCs) due to their air-stable, light-weight and conductive nature. To demonstrate their thermal stability as cathodes, PEDOT thin films coated via electrochemical polymerization on fluorine doped tin oxide (FTO) plates were sintered at different temperatures (50, 100, 150, 200, and 300 °C) for 1 h and a comparison was made with the as-prepared PEDOT thin films. We observed a negative temperature coefficient effect up to 200 °C along with lower surface roughness upon increasing the sintering temperature. Dye solar cells were fabricated using PEDOT thin films (sintered at different temperatures) and as-prepared PEDOT cathodes, and their respective performances were studied. The results showed increased efficiency with the increase in sintering temperatures of the cathode up to 200 °C (η = 4.33%) under the present experimental conditions. Cathodes sintered at 300 °C had poor electrochemical behavior and J-V performance, which may be due to polymer degradation.