High-frequency properties of oil-phase-synthesized ZnO nanoparticles

Monodispersive ZnO nanoparticles each with a hexagonal wurtzite structure are facilely prepared by the high-temperature organic phase method. The UV-visible absorption peak of ZnO nanoparticles presents an obvious blue-shift from 385nm of bulk ZnO to 369nm. Both the real part and the image part of the complex permittivity of ZnO nanoparticles from 0.1GHz to 10GHz linearly decrease without obvious resonance peak appearing. The real parts of intrinsic permittivity of ZnO nanoparticles are about 5.7 and 5.0 at 0.1GHz and 10GHz respectively, and show an obvious size-dependent behavior. The dielectric loss angle tangent (tanδ) of ZnO nanoparticles with a different weight ratio shows a different decreasing law with the increase of frequency.