Characterization of a white-colour DBD-driven cadmium bromide exciplex lamp

Abstract

The emission spectra from an atmospheric-pressure gas-discharge plasma in mixtures of cadmium dibromide vapour with gases (Ne, Ar, Kr, Xe and N2), as well as the temporal characteristics of voltage and current, have been investigated. A dielectric barrier discharge at a repetition frequency of sinusoidal voltage pulses up to 140 kHz was used to create the gas-discharge plasma. The discharge radiation has been analysed in the spectral range 200–900 nm with a resolution of 0.05 nm. In the spectra, the study has revealed radiation from CdBr(B–X, C–X) exciplex molecules, atomic lines of cadmium and rare gases, and in mixtures with xenon, radiation of XeBr(B–X, B–A) exciplex molecules. The most intense CdBr(B–X) radiation was observed in CdBr2/Xe mixtures. A discharge radiation of a silvery-white colour was observed when the temperature of the mixture was above 250 °C. The XeBr(B–X) radiation predominated in the spectra at temperatures of the mixture up to 200 °C. A further increase in the temperature resulted in the prevalence of the CdBr(B–X) radiation. Regularities in the spectral characteristics of the radiation from the gas-discharge plasma are discussed. The high-frequency atmospheric-pressure barrier discharge in mixtures of cadmium dibromide with gases can be used in multiwave exciplex lamps, operating in the UV and visible regions.