Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

Abstract

We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C) via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.g., 100 °C) together with pulsed UV light irradiation employing a commercially available, 325 nm UV diode (square, 1 min period, 15 mA drive current signal), results in an up to 80-fold enhancement in sensitivity to nitrogen dioxide. Furthermore, this combined operation method allows for making savings in power consumption that range from 35% to over 80%. These results are achieved by exploiting the dynamics of sensor response under pulsed UV light, which convey important information for the quantitative analysis of nitrogen dioxide.

Data_Sheet_1.PDF

“…The measured response times are comparable to the ones from commercially available gas sensors based on metal oxides (Hsu et al, 2007), and lower or similar than other In 2 O 3 octahedrabased gas sensors found in literature (Gonzalez et al, 2016). When RH was added as background gas, the resistance baseline and the response toward all the studied concentrations of EtOH decreased.…”

Using the Transient Response of WO3 Nanoneedles under Pulsed UV Light in the Detection of NH3 and NO2

“…This is reflected in Figure 1 . This ripple is considered a transient signal in sensor response and the rate of resistance change both when the UV is ON or OFF have been found to give useful information for determining gas concentration [ 29 ]. Especially the fact that the rate of resistance changes when the light is OFF will be explored here, since it can be assumed to be closely dependent on the adsorption and reaction processes taking place on the gas-sensitive surface.…”

“…UV promotes desorption of NO 2 and helps in regaining the sensor baseline. Recently, we introduced the use of pulsed UV light combined with thermal activation for measuring NO 2 using In 2 O 3 gas sensors [ 28 , 29 ]. Some preliminary results about the use of this technique in the measurement of NO 2 employing WO 3 sensors were presented in [ 30 ].…”

Light Activation of Nanocrystalline Metal Oxides for Gas Sensing: Principles, Achievements, Challenges

“…The widespread use of low-power UV LEDs to activate the sensor sensitivity of semiconductor oxides has led to increased publication activity in this area since the 2010s. To date, numerous studies have been published on the effect of UV radiation on the activation of the sensor sensitivity of semiconductor oxides, such as SnO 2 [ 35 , 36 ], In 2 O 3 [ 37 , 38 , 39 , 40 , 41 , 42 , 43 ], ZnO [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ], WO 3 [ 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ], and TiO 2 [ 60 , 61 , 62 , 63 , 64 ], of various morphologies. Despite the fact that in some cases the obtained materials demonstrated high sensor sensitivity, many authors noted the low selectivity of materials based on individual binary metal oxides.…”