Sensors, Vol. 19, Pages 4104: Novel Operation Strategy to Obtain a Fast Gas Sensor for Continuous ppb-Level NO2 Detection at Room Temperature Using ZnO —A Concept Study with Experimental Proof

Sensors, Vol. 19, Pages 4104: Novel Operation Strategy to Obtain a Fast Gas Sensor for Continuous ppb-Level NO2 Detection at Room Temperature Using ZnO—A Concept Study with Experimental Proof Sensors doi: 10.3390/s19194104 Authors: Ricarda Wagner Daniela Schönauer-Kamin Ralf Moos A novel sensor operation concept for detecting ppb-level NO2 concentrations at room temperature is introduced. Today’s research efforts are directed to make the sensors as fast as possible (low response and recovery times). Nevertheless, hourly mean values can hardly be precisely calculated, as the sensors are still too slow and show baseline drifts. Therefore, the integration error becomes too large. The suggested concept follows exactly the opposite path. The sensors should be made as slow as possible and operated as resistive gas dosimeters. The adsorption/desorption equilibrium should be completely shifted to the adsorption side during a sorption phase. The gas-sensitive material adsorbs each NO2 molecule (dose) impinging and the sensor signal increases linearly with the NO2 dose. The actual concentration value results from the time derivative, which makes the response very fast. When the NO2 adsorption capacity of the sensor material is exhausted, it is regenerated with ultraviolet (UV) light and the baseline is reached again. Since the baseline is newly redefined after each regeneration step, no baseline drift occurs. Because each NO2 molecule that reaches the senso...
Source: Sensors - Category: Biotechnology Authors: Tags: Article Source Type: research