Synthesis of zinc oxide nanoparticles using tea leaf extract and its application for solar cell

We report the synthesis of zinc oxide (ZnO) nanoparticles and its composite with natural graphite (NG) powder for application in solar cell. ZnO nanoparticles were synthesized using green tea leaf extract as non-toxic and eco-friendly reducing material under microwave irradiation. The formation of ZnO nanoparticles was monitored by the colour changes during the reaction. The synthesized ZnO nanoparticles were characterized by particle size analyzer (dynamic light scattering), scanning electron microscope, UV–visible spectroscopy, atomic force microscope and fluorescence spectroscopy. The average particle size of the ZnO nanoparticles was found to be 26 nm. The synthesized ZnO nanoparticles were further used to prepare ZnO/NG composite material with commercially available NG powder. The current–voltage (I–V) characteristics of thin film of ZnO/NG nanocomposite were investigated. J SC (short-circuit photocurrent), V OC (open-circuit photovoltage), FF (fill factor) and η (efficiency of the solar cell) were measured for ZnO/NG nanocomposite. Interestingly, the cell showed a good power conversion efficiency of 3.54% with high stability.