Papers by Keyword: SnO₂

Abstract: Advanced research in metal oxide-based nanotechnology has led to its broad applications, which include humidity sensors as well as electronic devices. Meanwhile, zinc oxide (ZnO)/tin oxide (SnO₂) composite nanostructure has established a presence in many electronic devices, and their performance can be further enhanced by electrospraying at high annealing temperatures. This paper explores how annealing temperature influences the structural properties and performance of ZnO/SnO₂ nanostructures in AZO-based humidity sensors. The ZnO/SnO₂ nanostructures were fabricated on AZO glass utilising electrospraying and then subjected to annealing at various temperatures: 100°C, 200°C, 300°C, 400°C as well as 500°C. The structural characteristics of the synthesized films were analysed utilising Field-Emission Scanning Electron Microscopy (FESEM) as well as X-ray Diffraction (XRD). Additionally, the humidity sensing performance of the films was evaluated based on their response time, sensitivity as well as recovery time. Following the results, a higher annealing temperature resulted in smaller crystallites and smaller diameters within the 71.6–91.9 nm range. Besides, the XRD patterns demonstrate a shift in the (002) peaks towards a higher angle value with incremental annealing temperature. In terms of the humidity sensing performance, the sensitivity level increased with increasing annealing temperature, while the recovery period and response time were reduced. In summary, the annealing temperature significantly influenced the performance of the ZnO/SnO₂ composite nanostructures, which recorded the best sensitivity of 173.10, 234 seconds response time, and 80 seconds recovery time after annealing at 500°C.

Abstract: Tin oxide (SnO₂) holds significance as an n-type semiconductor metal oxide, finding diverse applications across various fields. It has optimal properties as a gas sensing material, fuel cells, batteries, and so on. The main objective of this research is to synthesize SnO₂ thin films at a low-cost, easily replicable method and study its crystallographic properties. Here, the thin film was prepared by electrodeposition using tin sulfate, tartaric acid, and potassium nitrate at 2.1 pH followed by annealing the obtained thin film at 773 K. The whole process was conducted at 300 K without any external DC. The synthesized substrate was crystallographic properties were studied using X-ray diffraction. The average crystallite grain size was evaluated to be around 19 nm with degree of crystallinity close to 48.3%. These outcomes show that the method used to create thin films was in an appropriate direction.

Abstract: We report on an approach for the in-situ synthesis (chemical method based) of SnO-SnO₂ nanocomposites followed by characterisation (including morphological, chemical, structural and optical) and investigation of the electrical properties of the nanocomposites with reference to the as-synthesized SnO₂ nanoparticles. Compared to spherical SnO₂ particles, the SnO phase is found existing in the form of sheet like morphology. It has been found that through controlling of the Sn:OH precursor ratio is effective for the achievement of SnO phase. Compared to the pristine SnO₂ nanoparticles, the current-voltage (I-V) characteristics of the nanocomposites show the p-n junction characteristics. The observation of rectification ratio 2.05 indicates the excellent rectifying property of the nanocomposites due to the presence of p-type SnO phase. Further, exploration of the I-V characteristics has revealed the dominance of space-charge limited current transport mechanism for the nanocomposites sample. The lattice defects are discovered to be the cause of the transport mechanism in the nanocomposites sample.

Abstract: Praseodymium (Pr) doped (0.1 to 6 wt. %) nanostructured SnO₂ thin films are prepared via nebulizer assisted spray deposition process at a deposition temperature of 320 °C. The analyses show that the films grow in (110), (301) and (310) preferred orientations. The fabricated sensing films are exposed to LPG at 500 ppm concentration and at different operating temperatures. In 500 ppm of LPG, at an operating temperature of 350 °C, a commendable sensor response of 99 % with fast response time of 9 s and recovery time of 11 s is shown by 1wt.% Pr doped film, which is appreciable compared to pristine SnO₂ film. The sensor response reduces at lower operating temperatures. Microstructural investigations justify the gas sensing performance of 1 wt.% Pr doped SnO₂ thin film. Raman and photoluminescence studies give an insight into oxygen vacancies and trapped states that have a crucial influence on gas sensing.

Abstract: The production of nitrogen-doped carbon quantum dots (N-CDs) from walnut shell waste is crucially important for green chemistry and sustainable development. Herein we fabricate N-CDs by a bottom-up solvothermal method and use the novel N-CDs to modify the electron transport layer (ETL) in perovskite solar cells (PVSCs). The N-CDs can produce 440 nm fluorescence under the excitation of 350 nm light with a quantum yield of 8.75%. Infrared absorption spectra show that N-CDs contain high proportions of nitrogen-containing and oxygen-containing functional groups. , Through the incorporation of N-CDs into SnO2 ETL, the formation of defects is inhibited, and crystallinity is improved. This is because the N-CDs contains a large number of functional groups such as nitrogen and oxygen and these groups would interact with the ETL and perovskite, which reduce the defect/trap centers in PVSCs. Therefore, the N-CDs modified PVSCs show improved power conversion efficiency. This study provides a novel way to use walnut shell waste to synthesize N-CDs and achieve efficient and stable perovskites solar cells.

Abstract: The research on transparent heater (Thf) films rapidly increases due to their unique photoelectric properties, leading to new generation of optoelectronic device. Here, we report a simple method to fabricate transparent heater based on Al-doped SnO₂ (ASO) thin films. ASO films with 5 wt% Al as dopant were synthesized with various deposition times, namely, 5, 10 and 15 minutes using ultrasonic spray pyrolysis method. The correlation of deposition time on their structural characteristic, optical, electrical and thermal properties has been investigated. X-ray diffraction studies found that all samples exhibit tetragonal structure with preferred orientation along (110) plane. Meanwhile, the UV-Vis transmittance indicated that the sample having good optical transparency in visible light spectrum with the average transmittance up to 89.7%. The sheet resistance of ASO thin films was found to decrease as the deposition time increases to 10 minutes. Furthermore, Al-doped SnO₂ based transparent heater prepared with 10 minutes deposition time presents the excellent thermal temperature up to 76.3 °C at the applied voltage of 20 volt. The above findings reveal that Al-doped SnO₂ can be used as an alternative compound to substitute higher cost indium tin oxide as transparent heater. Keywords: aluminium, composite, spray pyrolysis, SnO₂, transparent heater

Abstract: In this study, SnO₂ nanoparticles of wt% 2, 4, 6, and 8 were uniformly composite in Bi₂Te₃ matrix. SnO₂ nanoparticle was synthesized using co-precipitation method. The result shows that based on XRD and EDS analysis the composites do not contain any impurities. The thermoelectric properties of the composites strongly depend on the Seebeck coefficient. The highest value of Seebeck coefficient of -177 µV/K is obtained at around 375 K for the 4% SnO₂/Bi₂Te₃ sample. This yields the highest value of the power factor of 4.0 × 10^-3 Wm^-1K^-1 compared to the pure Bi₂Te₃ synthesized using the same procedure by 14.3%. This result demonstrates that the thermoelectric properties of Bi₂Te₃ can be improved using oxide nanoparticles.

Abstract: Electron transport layer (ETL) plays an important role in improving the performance and stability of perovskite solar cells (PSCs). SnO₂ is a good semiconductor material with high electromigration and wide band gap. TiO₂ has the advantages of superior position of conducting band (CB), long electronic life and low preparation cost, so SnO₂ and TiO₂ are often used in ETL of PSCs. In this paper, the preparation progress of SnO₂, TiO₂ and SnO₂/TiO₂ composite ETL is reviewed.

Abstract: Tin oxide nanotubes (STs) were synthesized by the hydrothermal process using manganese dioxide nanowires (MWs) as a template and followed by oxalic acid treatment. The effect of the stannous chloride concentration on the structure and crystallite size of the product were investigated. The phase composition was determined by XRD. Morphologies were revealed by FESEM and TEM. Firstly, manganese dioxide nanowires were fabricated from KMnO₄. Then_, tin oxide nanoparticles were coated on the wall surfaces of MWs templates. The template was then leached out by oxalic acid treatment. Nanotubular structure of the final product was formed by the agglomeration of the tin oxide nanoparticles coating on the template surfaces. On increasing the stannous chloride amount, crystallite size and the electrochemical properties increased, while the specific surface area decreased.

Abstract: Metal organic chemical vapor deposition (MOCVD) was employed for the preparation of niobium (Nb)-doped SnO₂ films on SiO₂ glass substrates. The structure, optical and electrical properties of the Nb-doped SnO₂ films were systemically studied. The X-ray diffraction results indicated that the polycrystalline rutile SnO₂ films were obtained with a preferred SnO₂ [110] growth direction. Among which, the 5.4 at.% Nb-doped SnO₂ film showed the lowest resistivity of 1.0×10^-3 Ω∙cm and the highest Hall mobility of 74 cm²∙V^-1∙s^-1. The average visible light transmittance of the 5.4 at.% Nb-doped SnO₂ sample was more than 79%. The obtained Nb-doped SnO₂ films exhibited low resistivity, high Hall mobility and good transparency, which might have wide applications in electric and photoelectric devices.