Real-Time Tunable Gas Sensing Platform Based on SnO_(2) Nanoparticles Activated by Blue Micro-Light-Emitting Diodes

Micro-light-emitting diodes(μLEDs)have gained significant interest as an activation source for gas sensors owing to their advantages,including room temperature operation and low power consumption.However,despite these benefits,challenges still exist such as a limited range of detectable gases and slow response.In this study,we present a blueμLED-integrated light-activated gas sensor array based on SnO_(2)nanoparticles(NPs)that exhibit excellent sensitivity,tunable selectivity,and rapid detection with micro-watt level power consumption.The optimal power forμLED is observed at the highest gas response,supported by finite-difference time-domain simulation.Additionally,we first report the visible light-activated selective detection of reducing gases using noble metal-decorated SnO_(2)NPs.The noble metals induce catalytic interaction with reducing gases,clearly distinguishing NH3,H2,and C2H5OH.Real-time gas monitoring based on a fully hardwareimplemented light-activated sensing array was demonstrated,opening up new avenues for advancements in light-activated electronic nose technologies.

Chemoresistive materials for electronic nose:Progress,perspectives,and challenges

An electronic nose(e-nose)is a device that can detect and recognize odors and flavors using a sensor array.It has received considerable interest in the past decade because it is required in several areas such as health care,environmental monitoring,industrial applications,automobile,food storage,and military.However,there are still obstacles in developing a portable e-nose that can be used for a wide variety of applications.For practical applications of an e-nose,it is necessary to collect a massive amount of data from various sensing materials that can transduce interactions with molecules reliably and analyze them via pattern recognition.In addition,the possibility of miniaturizing the e-nose and operating it with low power consumption should be considered.Moreover,it should work efficiently over a long period of time.To satisfy these requirements,several different chemoresistive material platforms including metal oxides,organics such as polymers and carbonbased materials,and two-dimensional materials were investigated as sensor elements for an e-nose.As an individual material has limited selectivity,there is a continuing effort to improve the selectivity and gas sensing properties through surface decoration and compositional and structural variations.To produce a reliable e-nose,which can be used for practical applications,researches in various fields have to be harmonized.This paper reviews the progress of research on e-noses based on a chemoresistive gas sensor array and discusses the inherent challenges and potential solutions.