Rainer Hilbig

Low-pressure indium-halide discharges for fluorescent illumination applications

Low-pressure gas discharges of molecular radiators were studied for fluorescent lighting applications with a goal of reducing the energy loss due to the large Stokes shift in phosphors of conventional mercury-based fluorescent lamp technology. Indium halides (InCl, InBr, and InI) were chosen as the molecular radiators that generate ultraviolet to blue light emissions. The electrical characteristics and optical emission intensities were measured in discharges containing gaseous indium halides (InCl, InBr, and InI) as molecular radiators. The low-pressure discharges in indium halide vapor showed potential as a highly efficient gas discharge system for fluorescent lighting application.

Novel Molecular Discharge Light Sources

A systematic investigation into transition metal halides and oxides showed the high potential of transition metal oxides as visible radiators for highly efficient gas discharge light sources. Zirconium monoxide (ZrO) has been identified as the most promising candidate combining highly attractive green and red emission band systems with very high dissociation energy (8.2 eV) which ensures that the molecule is stable even at the hot plasma centre. Thus far, however, it has been impossible to keep ZrO in the gas phase of a closed discharge vessel, because at wall temperature usually compounds are formed which have negligible vapour pressures. We succeeded in establishing a regenerative chemical cycle by filling ZrX4 (X = Cl, Br, I) together with a stable, but volatile oxygen compound (like MoO2X2) and realized thus highly attractive, novel gas discharge light sources.