Designing SnO₂ Nanostructure-Based Sensors with Tailored Selectivity toward Propanol and Ethanol Vapors

Abstract

The application of metal oxide-based sensors for the detection of volatile organic compounds is restricted because of their high operating temperatures and poor gas sensing selectivity. Driven by this fact, we report the low operating temperature and high performance of C 3 H 7 OH and C 2 H 5 OH sensors. The sensors comprising SnO 2 hollow spheres, nanoparticles, nanorods, and fishbones with tunable morphologies were synthesized with a simple hydrothermal one-pot method. The SnO 2 hollow spheres demonstrated the highest sensing response (resistance ratio of 20) toward C 3 H 7 OH at low operating temperatures (75 °C) compared to other tested interference vapors and gases, such as C 3 H 5 O, C 2 H 5 OH, CO, NH 3 , CH 4 , and NO 2 . This improved response can be associated with the higher surface area and intrinsic point defects. At a higher operating temperature of 150 °C, a response of 28 was witnessed for SnO 2 nanorods. A response of 59 was observed for SnO 2 nanoparticle-based sensor toward C 2 H 5 OH at 150 °C. This variation in the optimal temperature with respect to variations in the sensor morphology implies that the vapor selectivity and sensitivity are morphology-dependent. The relation between the intrinsic sensing performance and vapor selectivity originated from the nonstoichiometry of SnO 2 , which resulted in excess oxygen vacancies (V O ) and higher surface areas. This characteristic played a vital role in the enhancement of the target gas absorptivity and the charge transfer capability of SnO 2 hollow sphere-based sensor.

Low-temperature solution-processed SnO2 electron transport layer modified by oxygen plasma for planar perovskite solar cells

“…Both LT- and LTP-SnO 2 films exhibited two peaks at binding energies of 487.3 and 495.7 eV corresponding to Sn 3d 5/2 and Sn 3d 3/2 , as previously reported. 31 The single peak at 487.3 eV is assigned to the Sn 4+ oxidation state of SnO 2 . However, there is no visible peak at the binding energy of 485.8 eV that corresponds to the Sn 2+ oxidation state which indicates the formation of SnO.…”

Using the electron spin resonance to detect the functional centers in materials for sensor devices

“…• defects is morphology-dependent and supporting the idea to exploit the controlled generation of these defects not only for boosting the electrical response but also the selectivity of the sensors [44].…”

Role of topological surface states and mirror symmetry in topological crystalline insulator SnTe as an efficient electrocatalyst

“…45 It has also been reported that the Sn 4+ and Sn 2+ peaks have symmetric shapes. [51][52][53][54] In the top graph of Fig. 6b, the raw data of the Sn 3d 5/2 peak with background subtracted are shown together with two symmetric fitted curves of Sn 4+ and Sn 2+ ; however, the overall fitted curve in red does not fit the raw data well.…”