US 8,790,614 B2 · ZnO structures and methods of use

Abstract

ZnO structures comprising crystalline ZnO micro or nanorods and methods for making and using these ZnO structures are provided. The side surface of the central portion of each rod may comprise planes of the form {1 0 −1 0}, {0 1 −1 0}, {−1 1 0 0}, {−1 0 1 0}, {0 −1 1 0} or {1 −1 0 0}, with central edge regions including a crystallographic plane of the form {2 −1 −1 0} or {−2 1 1 0}. The tip of the rod may comprise planes of the form {1 0 −1 1} {0 1 −1 1}, {−1 1 0 1}, {−1 0 1 1}, {0 −1 1 1} or {1 −1 0 1} with tip edge regions including a crystallographic plane of the form {2 −1 −1 2} or {−2 1 1 2}. The rods may be joined at or near their bases to form a “flower-like” morphology. In an embodiment, a synthesis mixture is prepared by dissolving a zinc salt in an alcohol solvent, followed by addition of at least two additives. The zinc salt may be zinc nitrate hexahydrate, the first additive may be benzyl alcohol and the second additive may be urea.

Claims22

Dependent claims

A zinc oxide structure comprising a plurality of microrods or nanorods, each rod exhibiting the wurtzite crystal structure, the longitudinal axis of each rod being aligned with the <0001> direction of the wurtzite crystal structure and each rod including

a. a central region, the surface of the central region including
i. six central facets, each central facet corresponding to a crystallographic plane of the form {1 0 −1 0}, {0 1 −1 0}, {−1 1 0 0}, {−1 0 1 0}, {0 −1 1 0} or {1 −1 0 0};
ii. six central edge regions, each central edge region being located between two central facets and including a crystallographic plane of the form {2 −1 −1 0} or {−2 1 1 0};
and
b. a tip region connected to the central region, the width of the rod in the tip region being less than that in the central region
wherein the surface of the central region, the tip region or a combination thereof includes a plurality of pits, the distance spanning each pit being from 1 nm to 200 nm.

3 more elements

A zinc oxide structure made by a method comprising the steps of

a. preparation of a mixture of
i. a zinc salt or a hydrated zinc salt, the zinc salt being selected from the group consisting of zinc nitrate, zinc acetate, zinc citrate, zinc methacrylate, zinc sulfate and zinc oxalate;
ii. a first additive, the first additive being an alcohol comprising a phenyl group;
iii. a second additive selected from the group consisting of urea, a urea derivative, thiourea, a thiorurea derivative and combinations thereof;
and
iv. an aliphatic alcohol solvent, the aliphatic alcohol having from 1 to 3 carbon atoms;
b. heating the mixture of step a) to a first temperature from 180° C. to 200° C. and maintaining the mixture at the first temperature for a time from 1 to 12 h;
c. heating the mixture of step b) to a second temperature from 240° C. to 300° C. and maintaining the mixture at the second temperature for a time from 1 to 12 h;
d. removal of the alcohol solvent from the mixture of step c) and
e. calcination in air of the mixture of step d),
wherein the zinc oxide structure comprises a plurality of microrods or nanorods, each rod exhibiting the wurtzite crystal structure, the longitudinal axis of each rod being aligned with the <0001> direction of the wurtzite crystal structure and each rod including a central region, the surface of the central region including six central facets and six central edge regions, each central edge region being located between two central facets and a tip region connected to the central region, the width of the rod in the tip region being less than that in the central region;
the surface of the zinc oxide structure including a plurality of pits, the distance spanning each pit being from 1 nm to 200 nm.

9 more elements

Dependencies are inferred from the claim text.

ZnO structures and methods of use

Life of this patent

ZnO structures and methods of use

Life of this patent

Abstract

Claims22