Various shaped-ZnO nanocrystals via low temperature synthetic methods: Surfactant and pH dependence

Abstract

ZnO nanocrystals, rod-, carnation-, and flower-like structures, have been synthesized in a high yield through low-temperature synthetic methods. Well-aligned ZnO nanorods having hexagonal wurtzite structure were grown on the ZnO thin films assembled by a spin-coating method. The morphologies of ZnO seed films are affected by pHs of sol-gel solutions, resulting smaller sizes and homogeneous roughness at higher pHs and higher number of spin-coating times. The carnation-like structures, average size of about 2-3 mu m, were assembled by tens of uniform ZnO nanosheet petals of similar to 50 nm in thickness when a different volume ratio of the precursory solution was used. ZnO nanocrystals on the facets of the compact ZnO nanorods have grown to linear nanorods having an average diameter of similar to 500 nm and length of similar to 2 mu m. Furthermore, a noticeable difference in the growth of ZnO nanocrystals in the presence of various surfactants, polyvinylpyrrolidone, polyvinylsulphonic acid, and polyethyleneimine, has been observed and discussed. (C) 2013 Elsevier Masson SAS. All rights reserved.