Feature: Optoelectronics and LEDs


UVC LEDs on course to displace mercury vapour lamps


By Gary Kardys, Head of Marketing, Marktech Optoelectronics


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ecent advancements in ultraviolet-C (UVC) LED efficiency, lifetime, wavelength control and economics are pushing semiconductor- based UV sources closer than ever to displacing mercury (Hg) vapour lamps in many applications. The trend mirrors the transition


from blue and white LEDs to filament-based lighting across the consumer, industrial and automotive markets. For decades, low-pressure mercury vapour lamps were the


dominant ultraviolet sources for analytical instrumentation and germicidal disinfection. Much like incandescent and tungsten-filament lamps once defined visible-light lighting, mercury lamps set the baseline for UVC systems in spectroscopy, water treatment and air disinfection. However, compared to older incandescent or tungsten filament lights, LED lighting is ten times more efficient and lasts up to 50 times longer. Also, being solid-state devices with no filaments or electrodes, they pose no risk of explosions and contain no mercury or hazardous compounds – another key driver for the displacement of mercury vapour lamps. Japan has already banned mercury in products, and the EU, US and Canada are on course to do so, too.


Wall plug efficiency: closing the gap To date, however, UVC LEDs have been constrained by their low wall-plug efficiency (WPE), which is typically below 1%. WPE is a measure of optical power output as a percentage of the electrical power input. Over the past decade, improvements in epitaxial growth, substrate quality, light extraction and packaging have steadily increased their performance. Today’s commercially available UVC LEDs in the 275-280nm


range routinely achieve WPE of 5-7% (Figure 1), with several manufacturers touting wall-plug efficiencies of 10-12%. In the lab there are even higher efficiencies achieved.


26 September 2026 www.electronicsworld.co.uk


Figure 1: 280nm UVC LED with four chips for high optical power output [Image: NKFG]


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