Feature: Optoelectronics and LEDs


SWaP characteristics of electronic components are critical in electronic design engineering as the market continues to demand greater miniaturisation and efficiency


Among them are wearable or portable biomarker sensors, various analyzers and spectrometers, feedback-controlled UV disinfection systems, and more. Mercury lamps emit a fixed spectral line at 253.7nm,


regardless of the application requirements. UVC LEDs, however, can be engineered to emit at specific wavelengths across the 230-280nm UVC range as well as in the UVA, UVB, visible and infrared spectral regions. This wavelength tunability enables improved signal-to-noise in sensors, multi-wavelength analytical instruments, and selective absorption measurements, among others. Using multiple addressable UVC LEDs with different


wavelengths, combined in the same package or board, enables quantification of chemicals, gases and biomarkers. In sensor or analytical applications, specific wavelengths


can be selectively enabled or disabled, and absorption can then be measured with photodetectors. For instance, a multi- wavelength device with 260nm and 280nm UVC LEDs can assess DNA purity because protein absorbs at 280nm and DNA absorbs at 260nm. In a multiple-wavelength UV germicidal irradiation (UVGI)


system, 280nm LEDs could be operated continuously to penetrate and destroy proteomic microbial films; 255nm LEDs could be used for DNA destruction; and 235nm LEDs could be used with high-current, short-pulse emission to delay bacterial regrowth. Another advantage of UVC LED light sources is the ease of


integration with photodiode detectors. Photodetectors such as silicon carbide (SiC) photodiodes can be co-packaged with UVC LEDs to monitor LED output. A photodiode can’t be included in a mercury vapour lamp because the high heat and corrosive Hg vapour would destroy the detector. New NSF standards for NSF Class A UVC-based water purifiers require a detector to ensure the water stream is fully irradiated.


Design considerations Size, weight and power (SWaP) characteristics of electronic components are critical in electronic design engineering as the market continues to demand greater miniaturisation and efficiency. A UVC LED has a much smaller footprint than even the smallest Hg vapour lamps, which is an important consideration in designing sensors and instruments – especially in sensing devices. In some sensor applications,


28 September 2026 www.electronicsworld.co.uk


high optical power output is not needed. In fact, a UVC LED with lower power draw and output can be desirable, extending battery life in remote or field-based monitoring systems. UVC LEDs are inherently compact, enabling miniaturised


sensor heads, dense multi-emitter arrays, integrated emitter- detector modules, and portable and wearable UV systems for wound healing and diagnostics. Whereas, mercury lamps, even at low power, require bulky glass envelopes, ballasts, and mechanical supports that limit design flexibility. All these features make UVC LEDs very useful in


applications like portable and battery-powered systems, medical wearable devices, embedded sensors and instruments, smart UV systems with feedback control, and consumer products which include disinfection robot. The extremely compact size of UVC LEDs could enable


disinfection inside small tubes or endoscope components, which would be impossible with a bulky mercury vapour lamp. A medical device engineering and design company, egoHealth, has developed a 275nm UVC LED-based wearable device, Stet Clean, for sanitizing stethoscopes, which should reduce transmission of harmful bacteria between patients. In the US, methicillin-resistant Staphylococcus aureus,


otherwise known as MRSA, and other antibiotic-resistant infections affect 2.8 million people, causing over 35,000 deaths. Several researchers are developing UVC LED based devices to disinfect drug-delivery devices (syringes) and injection sites, as well as UVC LED bandages. Surgeon Dr Mark Gerber at Spectrum Medical Technologies, has developed and patented a body-worn device that uses 235nm UVC LEDs to reduce surgical site and chronic wound infections. The small form factor and precise UVC wavelengths


are enabling technologies for UVC disinfection wearables. Bandages with integral biosensors for monitoring wounds are also being developed.


A familiar technology curve The trajectory of UVC LEDs increasingly resembles the early evolution of visible LEDs. Initial limitations in efficiency and cost delayed adoption, but once performance crossed key thresholds, system-level advantages accelerated displacement. In many sensing, analytical instruments and smart UVGI


applications, such as point-of-use or point-of-entry water purifiers, UVC LEDs have already reached that inflection point. For high-power municipal water purification, mercury lamps remain entrenched – for now. But as WPE improves and $/J continues to fall, the balance is shifting. Just as filament lamps once seemed indispensable, mercury-


vapour lamps are beginning to look like legacy technology, one increasingly challenged by compact, controllable, wavelength-specific solid-state UVC LEDs. Overall, the numerous advantages of current UVC LEDs, combined with semiconductor manufacturers’ ongoing technological advancements, indicate that the tipping point at which UVC LEDs displace mercury vapour lamps is close at hand.


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