Tin (IV) Sulfide chemoresistivity: A possible new gas sensing material

Abstract

In the last years, the research in the gas sensor field had a significant upward thrust. Regarding the chemoresistive gas sensors, this has produced a remarkable study of metal oxides semiconductors which, however, have shown different limits. In particular their low selectivity and lack of stability take them to an unreliable responses over time. For this reason, in this work it was decided to study the chemoresistive behavior of a non metal oxide semiconductor as Tin (IV) S ulfide (S nS 2 ). S nS 2 nanoparticles was synthetized by precipitation reaction in aqueous solution. Then, structural chemical and morphological characterizations were carried out by means of X-Ray Diffraction and S EM techniques. Furthermore, the thermal stability of the powder was studied with thermogravimetric analysis. The sensitive films were obtained by preparing a screenprinting paste and then depositing it on alumina substrates by means of screen-printing technique. The sensing properties of the obtained devices were tested with several gases at different working temperatures. At the best working temperature, a high selectivity to ketones and aldehydes, with respect to different types of molecules, was observed.

Impact of deposition temperature on the properties of SnS thin films grown over silicon substrate—comparative study of structural and optical properties with films grown on glass substrates

“…The obtained results show also that the optical properties of SnS films is better when films were deposited onto glass substrates. However, the high crystalline defaults observed for films deposited onto silicon substrate as well as the porosity nature of the films, suggest their potential application as gas sensors [40][41][42].…”

Metal Sulfides as Sensing Materials for Chemoresistive Gas Sensors

“…Electrical characterization covered a broad selection of gaseous compounds. CdS-based sensors were selective to alcoholic groups ( Figure 6 a), as reported in [ 42 ], whereas SnS 2 layers were capable of discriminating between the carbonyl groups of aldehydes and ketones, as reported in [ 40 , 41 ], as well as the hydroxyl group of the alcohols ( Figure 6 b). The response time as well as the recovery time was in the order of a few minutes for both sensing materials, similar to those of traditional metal oxides [ 54 ].…”

“…The additional characterizations, as reported in [ 40 , 41 ], allowed obtaining a very high chemical purity of SnS 2 . The clusters observed in SEM images are composed by structures with nanorod-like morphology.…”

“…In the study here presented, which is an extension of preliminary works on the sensing properties of metal sulfides [ 40 , 41 , 42 ], CdS and SnS 2 were tested with 13 gases, which belong to different chemical classes, in thermo-activation mode. The behavior was investigated in dry and humidity conditions.…”

“…The performance of the sensing films was investigated at operating temperatures ranging between 150 °C and 300 °C for SnS 2 -based sensors, and between 150 °C and 350 °C for CdS-based sensors. Higher temperatures must be avoided with these materials because they oxidize at temperatures of 400 °C and 500 °C for SnS 2 and CdS, respectively [ 40 , 41 , 42 ]. For this reason, we decided to test these sensors at temperature fairly lower than their critical temperature.…”