Effect of Reaction Temperature on the Structural and Optical Properties of Zno Nanocrystals

ZnO-based nanostructures have received broad attention due to their potential application in nano-electronics and photonics. We present here the results of our current efforts on synthesis of highly monodisperse ZnO nanocrystals. Stable suspensions of these nanocrystals were produced in ethanol solutions in the temperature range between 0oC and 60oC and atmospheric pressure conditions. Controlled addition of n-heptane to the stable nanocrystals suspension aged at different times, allowed their coagulation and consequent inhibition of crystal growth. Coagulated nanocrystals were easily re-dispersed in fresh ethanol solution. The high monodispersity and crystallinity of the nanoparticles were evidenced by HRTEM analyses of the suspensions. UV-visible and photoluminescence measurements confirmed not only the nanometric size of the crystals but also evidenced the continuous growth of the nanocrystals when aged in their mother liquors. The variation in crystal size as a function of synthesis temperature, aging time and the corresponding structural and optical properties of synthesized nanocrystals will also be discussed.