| Is Part of |
Open readings 2023: 66th international conference for students of physics and natural sciences, April 18-21, 2023, Vilnius, Lithuania: annual abstract book / editors: M. Keršys, Š. Mickus.. Vilnius : Vilnius University press, 2023. p. 101.. ISBN 9786090708835 |
| Abstract [eng] |
With the consumption of traditional fossil energy and worsening of the environment, the development and utilization of renewable energy become extremely urgent contemporary [1]. Due to their unstable output of energy, electrochemical energy storage devices are key technologies to adjust and accelerate the effective application of green energy [2]. Supercapacitors, as necessary energy storage devices, have gained progressively more attention due to their excellent properties, such as high power density, long cycle life, fast charge-discharge process, and environmental friendliness [3]. One of the most difficult challenges is the development of thin films based on an inexpensive and simple process using materials of high abundance. It is very important to find cheap, environmentally friendly products that have the possibility of deposition in a large area and that adhere well to the substrate method. The aim of the work was to form environmentally friendly thin tin sulfide films by applying the safety and inexpensive SILAR method and using "green" precursors, aqueous solutions, low deposition temperature, and environmental safety reducing agent. The use of Lascorbic acid for chemical synthesis is relatively new and less explored. Fluorine-doped Tin Oxide (FTO) glass slides were used as a substrate for the deposition of thin films of SnS. Two high abundance precursor solutions were used for the deposition: tin(II) chloride and sodium disulfide. The reaction between tin ions complexed by ascorbic acid and sulfide ions resulted in the formation of tin sulfide film. Thin films of tin sulfide had a blackish brown color. The deposited films were uniform, without any slots, pinholes. Thin films adhere to the substrate by Van der Waals forces and based on these forces crystals possess unique physical and chemical properties. These properties,including a large surface area to volume ratio, high tensile strength, and novel electronic band structures that do not have counterparts in traditional systems, have been widely researched. The composition, optical and electrochemical properties of the deposited films were characterized. Scanning electron microscopy images allowed us to examine the microstructure of the samples. Tin sulfide is formed of irregular morphology nanoparticle clusters, which are densely packed. X-ray diffraction (XRD) patterns show the formation of orthorhombic phases, mainly SnS. The peaks of SnO2 which are on the top of the substrate were also indicated. To summarize the acquired results, more intensive SnS peaks are observed when using 30 SILAR cycles, and their prolongation is clearly seen with an increase in the amount of L-ascorbic acid. Tin sulfide films deposited on FTO glass slides were found to consist of an average crystallite size of 9 to 10 nm and 11 to 15 nm for films obtained using 20 and 30 SILAR deposition cycles, respectively. The Raman study together with the X-ray diffraction confirms the growth of single-phase SnS films. The band gap of the samples was in the range of 1.1-1.4 eV, and the value clearly depends on the deposition conditions. Electrochemical measurements showed meaningful results. It appears that both the number of cycles and the quantity of ascorbic acid have a certain influence on the performance of films in this potential range. Generally, the higher number of SILAR deposition cycles increases the mass of films and, therefore, the current density is enhanced by the reactions occurring in the deeper layers of the active substance. Taking into account the impact of ascorbic acid, a higher amount has a positive effect when using 20 SILAR cycles. Presumably, this may be due to the higher probability of intercalation of ions and organic fragments between layers during the SILAR synthesis. When 0.8 g of ascorbic acid was used, a significant increase in specific capacity and specific energy was observed due to an increase in the number of SILAR cycles. The tin sulfide film prepared using the lowest amount of ascorbic acid is able to generate the specific capacitance of 6.35 F·g-1 with the best specific energy value of 3.53 Wh·kg-1. These results confirmed that obtained tin sulfide films on FTO glass are a promising material to be used as a supercapacitor. In this paper, we describe a simple, eco-friendly method for the synthesis of tin sulfide nanoparticles stabilized with L-ascorbic acid. The results obtained showed that SnS thin films demonstrate the possibility of using them in electrochemical capacitors. |
