Preparation And Microwave-absorbing Property Of One-dimensional(1D) Zinc Oxide

ZnO is a direct and wide band gap semiconductor of II-VI group. ZnO nanostructured materials are the excellent unity of nanomaterials and semiconductors which can be widely applied for LCD displays, solar cells, protecting coatings, gas sensors, solid illuminations and UV optical devices. Although fabrication of ZnO nanomaterials has reached new high level, it still exist many problems which are hard to solve. Synthesis of ZnO zero-dimensional materials has made great development. But the synthesis of one-dimensional(1D) and two-dimensional(2D) materials is still challengeable. This paper focus on the preparation of the one-dimensional(1D) materials and their properties of electromagnetic and microwave absorption.In this paper three simple preparation methods (solution growth, electric field auxiliary and electrostatic spinning) were used to synthesis quasi one-dimensional (1D) ZnO, including many needle, rod-like, long rod and fiber network. Their properties of electromagnetic and microwave absorption were studied. The structure, morphology, electromagnetic performance and microwave absorption were tested by scanning electron microscope, high depth of field electron microscope, X ray diffractometer and microwave vector network analyzer. The characterization results were analyzed and discussed.The influence of different template agent for zinc oxide structure was studied by the solution growth method. The needle zinc oxide (diameter about500nm, length to diameter ratio for10or so) was synthesized by using the HMTA. The influences of the different reaction time and concentration for the morphology were explored and the growth mechanism of the needle zinc oxide was explained. By the electric auxiliary, one-dimensional(1D) zinc oxide of large length to diameter ratio (diameter about300nm, length to diameter ratio of100) was synthesized. The morphologies of different external voltage and the growth mechanism were researched. By the electrostatic spinning, the fiber network zinc oxide (diameter in the range of300nm to500nm, staggered mesh) was synthesized. The fiber network morphology for the different concentration of precursor solution and applied voltage were studied.The electromagnetic performance and microwave-absorbing property of different morphologies were analyzed. The microwave absorption ability of fiber network sample is strong. The microwave attenuation of the mixture of power sample and paraffin at the mass ratio of3:1can reach27.8dB at10.7GHz. The maximum microwave attenuation of the needle zinc oxide sample is about17dB. The microwave-absorbing property of the stick zinc oxide is related with length to diameter ratio, whose maximum attenuation is in the range from5dB to lOdB. The microwave-absorbing property of spherical zinc oxide sample is weak. The maximum attenuation is below3dB. The microwave-absorbing property of different morphologies of zinc oxide is different. In this paper, the mechanism of the microwave absorption is mainly the dielectric loss, including relaxation polarization of ZnO46-intermediate ligand, interfacial polarization and space conductive network effect. One dimensional zinc oxide(long rod, needle, fiber network) have a strong attenuation of steering polarization, interface polarization and electric conduction. With the tendency, spherical, rod-like, long rod, needle and fiber network, the interface defects of zinc oxide increases, the interface charge polarization effect enhanced, the relaxation attenuation also increases. Space conductive network effect exists in one dimensional zinc oxide. The fiber network has many vacancy defects, its space network is complex, its conductivity loss is great. So the microwave attenuation ability of it is strong.