Synthesis of TiO2 nanoparticles at low hydrothermal temperature and its performance for DSSC sensitized using natural dye extracted from Melastoma malabathricum L. seeds

Efficiency of a dye-sensitized solar cell (DSSC) device depends on its semiconductor layer and the sensitizing dye to absorb the light. This work seeks to obtain the best solvent for the natural dye extraction from Melastoma malabathricum L. seeds. The extracted dye is used as sensitizer on TiO2 nanoparticles produced via hydrothermal but optimized at relatively low temperature. Infrared characterization of the extracted dyes showed differences in functional groups using different solvents, whereas ultraviolet visible examination of the dyes showed differences in intensity along the spectrum ranges of 600 to 400 nm with maximum absorption around 550 to 500 nm. Thermal analysis revealed that the natural dye should be stable around room temperature. Analysis on the synthesized TiO2 nanoparticles showed that the average crystallite size reported in the previous work is consistent with crystallite sizes observed in the transmission electron microscope images. Photoactivity examination showed that the DSSC sensitized using natural dye extracted with ethanol containing 20% distilled water on TiO2 synthesized at 150 degrees C has an efficiency of 5.7%, whereas the one on commercial TiO2 P25 Degussa has an efficiency of 3.0%. The DSSC device sensitized using commercial dye on TiO2 synthesized at 150 degrees C has an efficiency of 4.4%, whereas the one on TiO2 P25 Degussa has an efficiency of 4.0%. This result is promising for further development of the DSSC device using TiO2 nanoparticles synthesized at low hydrothermal temperature and sensitized with the natural dye.