www.advmatinterfaces.de FULL PAPER 1701492 (1 of 8) © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim A Combined Experimental and Computational Study of Gas Sensing by Cu 3 SnS 4 Nanoparticulate Film: High Selectivity, Stability, and Reversibility for Room Temperature H 2 S Sensing Thripuranthaka M, Neha Sharma, Tilak Das, Swapnil Varhade, Satish S. Badadhe, Musthafa Ottakam Thotiyl, Mukul Kabir,* and Satishchandra Ogale* DOI: 10.1002/admi.201701492 very important parameters in their perfor- mance evaluation. Hydrogen sulfide H 2 S is a toxic gas that has hazardous effects on the respira- tory system leading to neurological disor- ders as well. [1] H 2 S, also called sewer gas, is released during the decay of organic materials, septic systems during bacterial breakdown, and petroleum drilling and refining. Hence, the demand to investigate new functional materials for the detection of traces of H 2 S is quite relevant. Gas sensors have been fabricated using metal oxides, [6] polymers, [7,8] and organic– inorganic hybrid materials [9–11] for the sensing of a particular analyte. Metal oxide based sensors, for example, SnO 2 , [2,12,13] TiO 2 , [14] and CuO/ZnO [15] are the most investigated since they exhibit high sen- sitivity, fast response, and recovery. How- ever, they lack selectivity and possess safety and stability issues due to their high-temperature operation, [16,13] and the signal drift [17,18] with time hinders the integration and miniaturization of the devices. As possible alternatives to metal oxides, nanostructured metal sulfides (i.e., SnS 2 and Cu x S) [4,19–21] and 2D layered transi- tion metal dichalcogenides such as MoS 2 , [22] WS 2 , [23,24] and MoSe 2 [25,26] have been recently explored for NO 2 , NH 3 , and VOC sensing due to their tunable structural, electronic, and optical properties. Unfortunately, these materials are limited by their long response and recovery times and stability issues under ambient conditions. It has been reported that the decora- tion of noble metal nanoparticles (NPs) (Au, Ag, Pt) on metal oxides and metal sulfides enhances the performance of sensing materials in terms of their selectivity, stability, and recovery. [27] Nevertheless, this increases the cost and complexity of the syn- thesis and device fabrication. On the other hand, studies on the physical and chemical properties of metal chalcogenides have shown the competence of these materials to operate as sensors at low powers leading to conservation of energy and also from the safety point of view as they could be operated at low temperatures. [18] The relatively lower band gap of metal chalcogenides is an added advantage for application as compared to wide band gap of semiconduc- tors. This motivates one to explore metal sulfides for sensing applications. [18] Several binary sulfides are used for sensing of gases such as NH 3 , NO 2 , and H 2 , but not for H 2 S, especially at room temperature, because of the relative inactivity of metal sulfide surface bonds for this gas. The situation can be entirely different in the ternary case, however, due to the possible synergy of interactions involving dual cation surface chemistry. This is borne out by the present work wherein the Cu 3 SnS 4 material, the Cu-rich ternary sulfide used for the first time in the gas sensing context, not only senses H 2 S at room temperature but also remarkably does so with high selectivity and stability. Thus, a combined experimental and computer modeling study on the use of nanocrystalline orthorhombic Cu 3 SnS 4 phase is reported for H 2 S sensing. The material shows sensitivity for a wide range of H 2 S concentrations (from 10 to 2000 ppm). The performance of the sensing device fabricated on Kapton substrate remains intact even after several days and multiple bending cycles. Importantly, these experimental findings are consistent with the results of density functional theory calculations for binding energies for different gases, namely, H 2 S, NO 2 , NH 3 , and CO, on Cu 3 SnS 4 surface. T. M, Dr. T. Das, Dr. S. S Badadhe, Prof. M. Kabir, Prof. S. Ogale Department of Physics and Centre for Energy Science Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India E-mail: mukul.kabir@iiserpune.ac.in; satishogale@iiserpune.ac.in N. Sharma, S. Varhade, Prof. M. O. Thotiyl Department of Chemistry and Centre for Energy Science Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India Gas Sensors 1. Introduction Gas sensors play a vital role in the detection and control of ana- lytes in several sectors such as environmental pollution, food quality control, safety, medical diagnostics, and many other situ- ations/conditions faced in our daily life. [1] Of particular interest are sensors for the detection of toxic gases such as CO, NH 3 , NO x , H 2 S, and volatile organic compounds (VOCs). [2–5] Impor- tantly, such sensors are required to be highly selective, robust, reversible, stable, and low cost. With the growing emphasis of the modern world on wearable devices, there is an increasing demand for flexible sensors as well. In addition to the sensi- tivity, the response and recovery times of the sensors are also Adv. Mater. Interfaces 2018, 1701492