Detailed Analysis of the Growth Kinetics of ZnO Nanorods in Methanol

Abstract

The growth kinetics of ZnO nanorods in methanol is studied by a combination of scanning and high-resolution transmission electron microscopy and X-ray diffraction analysis. In the early stage of growth oriented attachment of 2−3 spheroidal crystallites to rod-like structures occurs. Later, rods of up to 90 nm in length with a hexagonal cross-section up to 18 nm in diameter form by ripening. Our main finding is that the growth follows a power law as a function of the ripening time with exponents of 0.32 to 0.39 for the length and 0.17 to 0.21 for the diameter. In contrast to previous studies on the growth of ZnO rods in alcohols our results indicate that the growth is dominated by anisotropic Ostwald ripening that is limited by volume diffusion.

ZnO superstructures via oriented aggregation initiated in a block copolymer melt

“…8(a) and as expected for ZnO. In fact, from the well-known Scherrer equation [11] the coherence length of the (101) reflection or rather [10−10] is 25.0 nm, whereas that of (002) or rather [0001] is 79.7 nm and that of (101) or rather [10−11] is 28.2 nm.…”

“…12,13 Also perpendicular to these (1010) facets, oriented attachment of primary ZnO particles to secondary particles or hierarchical superstructures is observed. 11,14 The latter superstructures are often denoted as mesocrystals. There are three principal pathways to explain the 3D self-organization of nanoparticles into a mesocrystal in compliance with the literature: i) nanoparticle alignment by electrical or magnetic (or both) fields, ii) epitaxial growth employing a mineral bridge and iii) spatial constraints (entropy driven).…”

Metal oxide semiconductor thin-film transistors for flexible electronics

“…Using approach (A), crystalline metal oxide semiconductors can thus be easily synthesized and further tailored through their size and shape. 240 There are, however, a number of drawbacks connected to approach (A). First of all, often a stable dispersion of the materials requires the use of additives or ligands (mainly insulating), which then need to be removed from the final film to improve the contact between particles.…”

Crystal structure transformation and dielectric properties of polymer composites incorporating zinc oxide nanorods

“…ZnO nanorods were prepared according to a modified method formerly reported by Host Weller et al [16][17][18] In brief, 21.95 g (0.1 mol) of zinc acetate dehydrate and 120 ml ethanol were placed in a flask equipped with a mechanical stirrer and thermometer. Firstly, the mixture was stirred at 70 °C for 30 minutes, then a solution of 7.2 g (0.18 mol) sodium hydroxide in 60 ml ethanol was added drop-wisely within 5 min.…”