RGB GaN Micro-LED Platform for Photo-Activated Gas Sensing

Conventional gas sensors rely on elevated temperatures to activate surface reactions, which raises power consumption, lengthens warm-up time, and complicates integration with compact electronics. We introduce a spectrally programmable platform that uses GaN-based red, green, and blue (RGB) micro-LEDs to photo-activate a broad class of sensing materials. The narrowband, high-radiance emission of each color enables wavelength-matched stimulation of materials whose optical absorption or defect states overlap with blue (~450 nm), green (~525 nm), or red (~630 nm) light. Selectivity and sensitivity are further enhanced by noble-metal decoration (Au, Pd, Pt), which adds catalytic pathways and, where applicable, plasmon-assisted hot-carrier effects while keeping power low. Our architecture places addressable micro-LED arrays beneath conformal sensing layers that can be implemented as thin films, nanostructured coatings, or particle assemblies. Candidate materials include conventional MOx (e.g., ZnO, SnO 2 , WO 3 , NiO, MoO 3 ) as well as 2D semiconductors (MoS 2 , WS 2 ), carbonaceous networks (rGO, CNTs), halide perovskites, porous frameworks (MOFs), and selected conductive polymers. This material-agnostic design allows each color to be paired with an optimally responsive material system and catalyst, enabling modular sensors tailored to different analytes without redesigning the optical/electronic stack. Under color-tuned, intensity-modulated illumination, photogenerated carriers and localized photothermal fields accelerate adsorption/desorption kinetics and surface redox reactions. In practice, color control lowers the required baseline temperature and produces multi-parameter responses—combining magnitude, response and recovery times, and partial pressures at half-response—that serve as compact, data-rich fingerprints. These features facilitate straightforward gas identification and concentration estimation using lightweight linear models, while remaining compatible with more advanced classifiers when needed. Using representative oxide and non-oxide materials with Au/Pd/Pt decoration, proof-of-concept devices show repeatable, reversible responses to oxidizing and reducing gases—including NO 2 , NH 3 , and H 2 —and to representative VOCs such as ethanol and toluene, operating from room temperature to mildly heated conditions. This work establishes a CMOS-compatible route to compact, reconfigurable, and energy-efficient gas sensors by coupling the spectral purity and speed of GaN RGB micro-LEDs with the rich surface chemistry of diverse sensing materials and noble-metal decoration. The approach reduces warm-up time and power while enhancing response and recovery, pointing to deployable solutions for environmental monitoring, industrial safety, and wearable/IoT applications.