Abstract:
This work aims to study the efficiency of converting sunlight into electricity of dye sensitized solar cell (DSSC). ZnO was used as a semiconductor and fabricated ZnO photoanode by the doctor blade method. The extracted noni leaves was used as a sensitizer and obtained the highest conversion efficiency in comparison to other natural dyes because it absorbed both visible and near infrared wavelength region which enhanced the efficiency of DSSC. Moreover, the efficiency of noni leaves-ZnO DSSC increased with respect to the thickness of ZnO films (from 4 to 12 micrometers). This is due to the increment of ZnO nanoparticles and consequently the augmentation of dye loading. In addition. the electrophoretic deposition (EPD) was employed to prepare ZnO film for photoanode in DSSC. The as-prepared ZnO films were smooth and uniform, and their thickness was increased with the increase in deposition voltage (from DC 15 V to 24 V) and deposition times (5 min to 20 min). As a consequence, the conversion efficiency of noni leaves-ZnO DSSC increased. The short-circuit current and conversion efficiency of DSSC increased because of the increment of ZnO contents and dye loading. On the other hand, the open-circuit voltage declined due to the possible charge recombination occurred. To improve the efficiency of the dye-sensitized solar cell, the polythiophene layer prepared by electropolymerization was fabricated on the as-prepare ZnO film. The hybrid polythiophene-ZnO DSSC showed the increase in efficiency. This result indicated that the dark current reduced and consequently improved the conversion efficiency of DSSC in the presence of the polythiophene layer.
