UV-activated gas sensing properties of ZnS nanorods functionalized with Pd

Enhanced NO 2 gas sensing performance of bare and Pd-loaded SnO 2 thick film sensors under UV-light irradiation at room temperature

“…Consequently, the number of electrons transferred to chemisorbed NO2 and the magnitude of the resistance change increases. Moreover, some authors also reported that NO2 is more easily adsorbed on Pd and then is spilled over to the SnO2 surface [19,[40][41][42][43]. Figure 11 shows the recovery times (trec) for some bare and Pd-loaded SnO2 sensors which were synthesized by the assistance of microwave irradiation.…”

“…Without UV-light irradiation, only O2 -can react at temperatures less than 100°C [27][28][29]. However, upon the UV-light irradiation, all oxygen adsorbates may be M a n u s c r i p t 19 accelerated. In addition, electron-hole pairs are generated and separated under the built-in electric field near the surface of SnO2 nanoparticles [29][30][31].…”

“…Moreover, enhanced response to 200 ppm LPG at room temperature for SnO2 thin films with different thickness has been achieved by applying a combined effect of UVlight irradiation and the presence of a Pt catalyst on the SnO2 surface [21]. Until now, many studies have been reported on the NO2 gas sensing properties of single [5,14,22] and composite [1,4,23] metal oxide materials under UV-light irradiation, while few studies have examined functionalized or noble metal-loaded metal oxide materials under the UV-light irradiation [18][19][20].…”

“…Moreover, more recently some researchers have experimentally found that the sensing response of ZnO under the UV-light irradiation at room temperature is not only dependent on the light wavelength and its intensity, but it can also be affected by the kind of target gases, crystal/grain size and photo-generated charge efficiency of the sensing material [15,16]. Recently, Lee et al [18][19][20] studied the gas sensing properties of ZnO and ZnS functionalized with some noble metals to NO2 gas and an enhancement in sensor response for functionalized semiconductors was reported. Moreover, enhanced response to 200 ppm LPG at room temperature for SnO2 thin films with different thickness has been achieved by applying a combined effect of UVlight irradiation and the presence of a Pt catalyst on the SnO2 surface [21].…”

“…There are several reports in the literature [14][15][16][17][18][19][20][21][22][23] on the gas sensing enhancement by UV-light irradiation at room temperature for both reducing and oxidizing gases. Enhancement of the NO2 response was also achieved by the UV-light irradiation on a SnO2 thin film at room temperature [14].…”