Optimization of TiO2 Based Henna Dye Sensitized Solar Cell using Grey-Taguchi Technique

Abstract

Low efficiency is a major drawback associated with Dye Sensitized Solar Cells (DSSCs). However, the efficiency can be enhanced by multi-objective optimization based on process parameters. In this work, four process variables have been identified as important parameters for influencing DSSC responses (efficiency, shunt and series resistance). These are thickness of the working electrode (A), annealing temperature (B), annealing time (C) and dye loading time (D). An optimal combination of the response parameters of the resulting DSSC was obtained by simultaneously adjusting these input parameters. With three different levels for each process variable, FTO glasses as components and henna leave extract as sensitizer, 9 unique DSSCs were fabricated following Taguchi Design of experiment. Each cell was illuminated with constant light intensity of 100 mW/cm 2 to measure the photovoltaic parameters. The optimal combination of process parameters was determined by applying Grey Relational Analysis (GRA). The experimental best condition (A 3 B 1 C 3 D 2 ) obtained from Taguchi array corresponded to average thickness of 9.67 µm for TiO 2 film , annealing temperature of 300 °C, annealing time of 6 hours and dye loading time of 4 hours. With optimization, the annealing time is reduced by ~67% with other responses remain the same. The global best DSSC has higher efficiency, higher shunt resistance and lower series resistance of 0.66 %, 24844.44 Ω and 8.4281 Ω, respectively. This translates to 1.3% higher efficiency, 12.4% higher shunt resistance and 10.8% lower series resistance. These results indicate that solar cell responses can be optimized significantly.