Generation of a large-scale homogeneous DBD using polyethylene terephthalate as dielectric material in open air

Dielectric barrier discharge (DBD) in open air usually operates in a filamentary mode, which limits the widespread application of DBD technology in the industrial field. In this Letter, a large-scale homogeneous DBD is obtained by using a wire mesh electrode in open air with a relatively high argon flow velocity. Polyethylene terephthalate (PET) is covered on a quartz plate, and they work together as dielectric materials. There is only one wide pulse of optical signal in each half voltage cycle for the homogeneous discharge. Fast photography reveals that the discharge is uniformly distributed over the entire electrode surface during the discharge period. When argon flow velocity is relatively low, the discharge is filamentous. There are multiple narrow optical signal pulses in each half voltage cycle for the filamentary discharge. Optical emission spectroscopy indicates that electron density (ne), electron temperature (Te), molecular vibrational temperature (Tvib), and gas temperature (Tg) decline in both homogeneous discharge and filamentary discharge with increasing argon flow velocity. Polyvinyl chloride and polypropylene dielectrics behave similar to PET for generating homogeneous discharge, which is of great significance for the uniform surface treatment of various materials.