AVS 57th International Symposium & Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS-ThP

Paper PS-ThP13
Synthesis of Zinc Oxide Nanoparticles Using an Atmospheric Pressure Plasma Jet

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Plasma Science and Technology Poster Session
Presenter: S.M. Chang, National Taiwan University, Taiwan, Republic of China
Authors: S.M. Chang, National Taiwan University, Taiwan, Republic of China
C.C. Hsu, National Taiwan University, Taiwan, Republic of China
Correspondent: Click to Email
Nanocrystalline zinc oxide particles have been synthesized using a gas-phase process by atmospheric pressure plasma jets (APPJ). The APPJ used is sustained by a repetitive pulse source with nitrogen or oxygen as the plasma gas. Zinc-containing salt solutions, namely Zn(NO3)2 and ZnCl2, are nebulized into μm-sized droplets and fed into the downstream of the APPJ. Liquid droplets undergo vaporization and reaction and form solid particles in the downstream of the jet. The particles are collected using de-ionized water or buffer solutions. The particle size and its distribution are measured using the dynamic light scattering method and scanning electron microscopy. It is found that the reactivity and the temperature of the jet downstream are able to efficiently convert the droplets into crystalline ZnO particles, as confirmed by the X-ray diffractometer. When O2 is used as the plasma gas, the fabricated ZnO particles readily dissolve in the particle-collecting solution due to the decrease in the pH of this solution. The pH drops to as low as 1 within 2 min. It suggests the need of using the buffer solution as the particle collector. When using N2 as the plasma gas, a relative small change in pH is found and results in decent collection yield. When using Zn(NO3)2 solution as the precursor under 275 V applied voltage and 30 ~ 60 slm N2 gas flow, the fabricated ZnO particles show a double-peak distribution: small and large particles with the averaged sizes of 120 nm and 1000 nm, respectively. Preliminary studies found that the particle size distribution can be altered by changing the precursor solution concentration, the carrier gas flow rate, and the plasma conditions. Finally, the potential using this apparatus to fabricate more complex metal oxides will be discussed.