Hydrothermal synthesis of highly crystalline Zn2SnO4 nanoflowers and their optical properties

The primary focus of this work is to identify the ideal conditions for synthesizing highly crystalline Zinc Stannate (Zn2SnO4) nanoflowers through green hydrothermal synthesis by optimizing the reaction time and temperature. The X-ray diffraction pattern of the samples show an enhanced crystallinity and phase formation of Zn2SnO4 nanoflowers with increase in reaction temperature and time, and the most beneficial condition was observed and validated at 220 °C for 48 h. Subsequent SEM and TEM investigations revealed that the samples exhibit nanoflower morphology composed of nanosheets and nanoneedles. The circular ring like pattern observed from selected area electron diffraction (SAED) establishes the well crystalline nature of nanoflowers. Optical absorption study revealed the band gap energy was slightly higher than that of the bulk Zn2SnO4, and the 400 °C annealed samples exhibited a red shift of the absorption edge compared with the as synthesized samples. The emission bands recorded at UV region and low visible region using room-temperature photoluminescence characterization indicated their high structural and optical quality.