Micro‐Schottky Junction‐Boosted Efficient Charge Transducing for Ultrasensitive NO2 Sensing

Abstract The detection of ultralow NO 2 for practical applications remains a significant challenge because the two critical characteristics of high sensitivity and good robustness are considerably unsatisfactory. Inspired by the classification of stimuli‐receiving and signal‐conveying for a stimuli‐responsive procedure of a neuron in organisms, an internal micro‐Schottky junction introduced into a chemiresistor is constructed as an efficient transduction strategy to boost the less concerned transducing stage for a further improvement in NO 2 sensing performance. The SnO 2 nanoflowers/reduced graphene oxide‐based chemiresistor achieves a response of 10.5 toward 10 ppt NO 2 , with a record‐breaking limit of detection of 0.73 ppt at room temperature as well as fast response and recovery times of 59 and 9 s at 10 ppt. Surprisingly, the sensor exhibits good robustness, including higher selectivity, long‐term stability, and process stability. A comprehensive analysis of the electrical properties and energy band of inorganic materials reveals that the ultrahigh sensitivity and faster response/recovery are primarily related to the efficient transducing ability arising from the rapid electron transport and signal‐amplifying effect contributed by micro‐Schottky junctions. The concept of affiliating the sensing material modulation to the recepting and transducing stages and considering comprehensively provides a novel insight into the enhancement of gas sensing performance.