High yield synthesis and characterization of aqueous stable zinc oxide nanocrystals using various precursors

• We report high (∼94%) yield synthesis of pure zinc oxide nanocrystals.
• Achieved stand-alone crystallite sizes in the range 13–35 nm.
• Observed that organic precursors yield smallest crystallite size compared to inorganic precursors.
• The stability of ZnO NCs in water has been verified on time scale for its practical applications.
• Easy and viable technique for mass production of ZnO NCs with narrow size distribution.

We report a high (∼94%) yield synthesis of intrinsic zinc oxide (ZnO) nanocrystal powders having crystallite sizes in the range 13–35 nm using a novel gel-incineration method with inexpensive precursor salts and citric acid as chelating agent. The influence of various precursor chemicals on the nanocrystallite size, morphology and luminescent properties has been studied in detail. It was identified that the ZnO nanocrystals prepared using organic precursor resulted the smallest crystallite size as compared to inorganic precursors. Reaction temperature was optimized to be ∼900 °C by simultaneous thermogravimetric analysis and differential scanning calorimetry studies. Morphology and microstructure of the ZnO nanocrystals have been studied using a scanning electron microscopy. Analysis of photoluminescence excitation and emission spectra enabled us to calculate the band gap energy and defect analysis of as prepared ZnO nanocrystals respectively. The stability of ZnO nanocrystals in water has been verified on time scale and its potential use has been successfully demonstrated for security marker applications.