Synthesis and characterization of porous ZnO nanoparticles by hydrothermal treatment of as pure aqueous precursor

The presence of the complexing agents in the growth solution poses risk of the unintentional doping in the synthesized product and hence is likely to adversely affect the intrinsic properties. Herein we report the synthesis of ZnO nanoparticles with porous microstructure using pure aqueous precursor. Crystalline ZnO nanoparticles were synthesized by thermal treatment of aqueous solution of zinc acetate in an open bath. The size of the nanocrystals was controlled by changing the initial precursor concentration. The structural and optical properties of the synthesized nanocrystals were analyzed by X-ray diffraction, high resolution transmission electron microscopy, UV–vis absorption and room temperature photoluminescence measurement techniques. The TEM and UV–vis spectral signature analyses confirmed the formation of dispersed single crystalline ZnO nanoparticles. The nanopowders were found to have disordered mesoporous structure. The synthesized nanocrystals exhibited characteristic band edge emission as well as to surface defect related deep level visible luminescence.

ZnO nanocrystals are predominately prepared by soft chemical methods such as sol–gel and hydrothermal. Although hydrothermal approach is very simple, complexing agents or mineralizers such as alkali metal hydroxide are generally used. There is always a high probability that these cations will be incorporated within the nanocrystals. Such unintentional doping is detrimental to the intrinsic property of the material and will impede its effective application. Here we report a very simple and effective hydrothermal approach to synthesize ZnO nanocrystal without employing any mineralizers.Figure optionsDownload as PowerPoint slideResearch highlightsThe manuscript reports synthesis of ZnO nanoparticle by simple thermal treatment of aqueous precursor without using any assisting mineralizing agent. The highlights of the findings are as follows: ▶ Aqueous synthesis of ZnO nanoparticles is demonstrated without using any mineralizer. ▶ The method minimizes the risk of unintentional doping due to mineralizers. ▶ The synthesized ZnO nanoparticles had a non-uniform mesoporous structure. ▶ The porous ZnO nanoparticls exhibited size dependent optical absorption.