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Effect of incorporation of sulphur on the structural, morphological and optical studies of CdSe thin films deposited by solution processed spin coating technique
摘要： Ternary compound semiconductor CdSexS1-x (x = 1, 0.8, 0.6, 0.4, 0.2 and 0) thin films were prepared on glass substrates by using simple solution processed spin coating technique. Cadmium acetate, sodium selenosulfate and thiourea were used as source materials for Cd2+, Se2? and S2? ions, while triethanolamine was used as a capping agent. The 25% concentred NH4OH solution was used as a complex reagent and also used to adjust the pH of the final solution ~ 11. The deposition conditions (rotation speed 2000 rpm for 30 s and substrate dried in the air at 120 °C for 2 min) were remain same for all the samples. The as-deposited thin films on glass substrate were annealed at 350 °C for 30 min. The X-ray diffraction pattern shows that all the samples were polycrystalline in the nature with hexagonal structure. The most of prepared thin films were highly textured along (002) plane and peak position for plane (002) is shifted with change in composition ‘x’. The average crystallite size in CdSexS1-x thin films were found between 62.6 nm to 93.4 nm. Scanning electron microscopy images showed uniform deposition morphology with spherical shaped grains distributed over entire glass substrate. Samples CdSe0.8S0.2 and CdSe0.6S0.4 thin films indicated interesting morphological features with the combination of spherical shaped nanoparticles and interconnected nanofibers which form hierarchical flowerlike micro-structure. Energy dispersive X-Ray studies confirmed that thin films were having approximately same stoichiometry of atomic ratio of elements Cd, Se and S as present in volumetric ratio of the reactants in chemical solution. Fourier transform infrared studies confirmed the formation of the Cd(Se,S) bonding in materials. The optical band gap of CdSexS1-x thin films were found as direct band gap in the range of 1.82 eV to 2.32 eV. As the incorporation of sulphur element increases, the band gap of CdSexS1-x thin film also increases. The CdSexS1-x thin films can be used as absorption layer in solar photovoltaic cell which is due to wide and fine tenability of the energy band gap.
关键词： Nanofibers,Spin coating,Absorption layer,cadmium sulfide,Cadmium selenide,Hierarchical flowerlike microstructure,Ternary compound semiconductor
更新于2025-11-21 11:18:25
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Morphology Tuning of ZnO/P3HT/P3HT-b-PEO Hybrid Films Deposited via Spray or Spin Coating
摘要： Hybrid films of zinc oxide (ZnO) and poly(3-hexylthiophen-2,5-diyl) (P3HT) show promising characteristics for application in hybrid bulk heterojunction solar cells (HBSCs). However, the incompatibility of ZnO and P3HT may lead to a reduced interface area, thus reducing the probability of exciton separation and consequently lowering solar cells efficiencies. Here, a diblock copolymer P3HT-b-poly(ethylene oxide) (PEO) is introduced to improve the interface between ZnO and P3HT. ZnO is synthesized via a block copolymer assisted sol-gel approach and the used zinc precursor is directly incorporated into the PEO blocks. Thus, the possibility of aggregation is reduced for both, the inorganic and the organic components and a good intermixing is ascertained. Two deposition methods, namely spray and spin coating are compared with respect to the resulting film structure, which is investigated with scanning electron microscopy (SEM) and time-of-flight grazing-incidence small-angle neutron scattering (TOF-GISANS) measurements. Both, the surface and inner morphologies reveal that the spin coated samples possess smaller and less diverse domain sizes than the sprayed films. Due to the advantage of spray coating in large-scale production, the morphology of the sprayed samples is tailored more meticulous by changing the weight fraction of ZnO in the films. The sprayed hybrid films show smaller domains and less aggregation with decreasing amount of ZnO. This reveals that both, the deposition method and composition of the ZnO/P3HT/P3HT-b-PEO hybrid films play an important role for the film morphology and thus for improving the performance of HBSCs in future application.
关键词： spray coating,morphology,spin coating,ZnO/P3HT/P3HT-b-PEO,TOF-GISANS
更新于2025-11-14 15:19:41
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Effects of the Electrode Modification Conditions on the Performance of Three-state Electrochromic Devices via Spin- coating
摘要： Electrodeposition-based electrochromic devices capture numerous attentions due to their simple sandwich-type structure, facile and low-cost fabrication, and promising application. Herein, titanium dioxide (TiO2) nanoparticles were modified onto fluorine doped tin oxide (FTO) electrode via spin-coating technique with different rotation speed and precursor solution concentration, followed by sandwiching a suitable amount of gel electrolyte between the modified FTO electrode and a flat FTO electrode to fabricate the electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror and black). A systematic study of correlation between electrode modification condition and morphological features of TiO2 thin films, as well as the performance of electrochromic devices, i.e. optical contrast, switching time, and cycling stability, were investigated. Optimized performances of three-stated electrochromic device could be obtained by properly manipulating the electrode modification conditions. The results in this study will provide valuable guidance for rational design of electrochromic device with satisfactory performance.
关键词： Morphological Features,Rotation Speed,Electrochromic Properties,Precursor Solution Concentration,Spin-coating,Electrochromic
更新于2025-09-23 15:23:52
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Influence of the precursor concentration on the morphological and structural properties of zinc oxide (ZnO)
摘要： Three precursor concentrations were used for synthesizing zinc oxide nanoparticules by sol-gel via spin-coating method. The final products were synthesized at calcination temperatures of 550 °C during 2 hours. X-ray diffraction (XRD) analysis showed that ZnO thin films were preferentially oriented along the (002) c-axis direction perpendicular to the substrate surface and had crystalline structure with a hexagonal wurtzite phase. EDX microanalysis and morphological investigations using SEM indicated respectively that the products consist of zinc (Zn) and oxygen (O) elements and the stoichiometric atomic ratio of Zn:O ? 1:1, and surface of nanoparticles is homogeneous. Comparing the XRD report of three samples, it has been concluded that samples prepared at 0.75M condition give high intensity of fine peaks and better improved properties with potential applications as transparent electrodes in optoelectronic devices such as solar cells. Therefore, this deposition condition can be used for further deposition condition for reproductivity in other research laboratories.
关键词： Spin-coating,properties,ZnO,influence of concentration
更新于2025-09-23 15:23:52
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On the anomaly in the electrical characteristics of thin film transistors with multi-layered sol-gel processed ZnO
摘要： A set of bottom-gate Zinc Oxide (ZnO) thin film transistors (TFTs) with active layers containing 1, 4 and 8 layers of spin-coated ZnO were fabricated and their electrical characteristics such as transistor transfer and capacitance-voltage characteristics were analyzed. The transconductance of the single-layered ZnO transistor shows a single peak. On the other hand, multiple peaks and humps were observed in the transconductance and capacitance-voltage characteristics of multi-layered ZnO transistors. The multi-layers were grown by reiteration of the spin-coating process, producing ZnO-ZnO interlayer-interfaces. The surface of the ZnO layer in contact with the ambient contains active sites, resulting in chemisorption of ambient gases such as oxygen prior to the deposition of subsequent layers. The chemisorbed species become negatively-charged and form charge sheets, depleting the surface/interface region. It was proposed that the formation of depletion layers at ZnO-ZnO interlayer-interfaces is the main cause for the observed anomaly.
关键词： Sol-gel,Zinc oxide,Spin-coating,Thin-film transistors,Electrical Properties,Interface Defects
更新于2025-09-23 15:22:29
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Synthesis and characterization of spin-coated clay/PVDF thin films
摘要： This paper reports the fabrication of Cloisite-15A (C-15A)-dispersed polyvinylidene fluoride (PVDF) nanocomposite thin films by spin coating and their characterization for sensor applications. The effects of nanoclay, duration of ultrasonication and spinning speed on the morphology and properties of thin films were studied. The influence of these parameters on the amount of β-phase was analysed using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) techniques. The influence of C-15A on the morphology and surface quality of thin films was analysed by scanning electron microscopy (SEM). Piezoelectric coefficient was measured at 110 Hz and 0.25 N. Contact angle was measured to assess the hydrophobicity of thin films. The β-phase of 82.97% was obtained in the specimens with 5 wt% C-15A, processed at 500 rpm and spun for 35 min. The piezoelectricity of the specimens increased from ?18 to ?25 pC N?1. Experiments were conducted as per L16 orthogonal array.
关键词： spin coating,Cloisite-15A,β-crystals,PVDF/clay thin films,piezoelectricity
更新于2025-09-23 15:22:29
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Setup to Study the in Situ Evolution of Both Photoluminescence and Absorption during the Processing of Organic or Hybrid Semiconductors
摘要： In situ measurement techniques, applied during the solution processing of novel semiconductors such as organic semiconductors or hybrid perovskites, have become more and more important to understand their film formation. In that context, it is crucial to determine how the optical properties, namely photoluminescence (PL) and absorption, evolve during processing. However, until now PL and absorption have mostly been investigated independently, significantly reducing the potential insights into film formation dynamics. To tackle this issue we present the development of a detection system that allows simultaneous measurement of full absorption and PL spectra during solution processing of the investigated film. We also present a spin-coater system attachable to the detection system, where the temperature of the substrate on which the film is processed can be changed. We performed test measurements by spin coating the well-known conjugated polymer P3HT demonstrating the potential of this technique. By considering absorption and corresponding PL, we extract the PL quantum yield (PLQY) during processing, which decreases with substrate temperature. Furthermore, we identify a significant red shift of the PL just prior to the onset of the aggregation process, indicating the importance of chain planarization prior to solid film formation.
关键词： photoluminescence,in situ measurement,organic semiconductors,hybrid perovskites,spin-coating,film formation,absorption,P3HT
更新于2025-09-23 15:21:21
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Thin Film Processes - Artifacts on Surface Phenomena and Technological Facets || Modified Spin Coating Method for Coating and Fabricating Ferroelectric Thin Films as Sensors and Solar Cells
摘要： Spin coating process with a modified spin coater is performed well, especially the second generation of modified spin coater, which has a maximum value of 18,000 rpm, is able for manufacturing/coating photonic crystal‐based ferroelectric thin films that require a high angular velocity (rpm). Ferroelectric thin films that use both 3000 and 6000 rpm have given good results in energy gap, electrical conductivity, etc. In addition, the modified spin coater has also produced several applications such as sensors in the device of blood sugar level noninvasively, sensors in the automatic drying system, sensors in the robotic system, and photovoltaic cells in the system of solar cells/panels which are being developed at present. These applications used ferroelectric material such as barium strontium titanate (BST), lithium niobate (LiNbO3), cuprous oxide (CuO), and lithium tantalate (LiTaO3).
关键词： ferroelectric thin films,solar cells,modified spin coating,sensors
更新于2025-09-23 15:21:21
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A novel CdTe ink-assisted direct synthesis of CdTe thin films for the solution-processed CdTe solar cells
摘要： The CdTe ink in thiol-amine cosolvents from CdTe powder has been successfully prepared via Triton X-100 surfactant at 50 °C. The CdTe thin films have been synthesized and characterized from the prepared CdTe ink using spin coating method. The SEM micrographs reveal that synthesized films are uniform, smooth and homogeneous with less cracks, voids and pinholes compared to the films deposited from the inks without surfactant. The XRD spectra confirm the mixed hexagonal and cubic structure of the deposited films. The Raman peaks at 142 and 122 cm-1 indicate the CdTe and the pure Te phase, respectively. The FTIR peaks at 1638 and 1384 cm-1 due to C=O and COO- groups originated for the stretching vibration of the ligands of the thiol-capped CdTe, and the absence of vibrational peaks of S–H in the range of 2550–2650 cm-1 confirms the thiol-capped CdTe, respectively. The EDX results reveal the existence of Cd and Te elements in CdTe films. The deposited films exhibit the highest absorbance (*85%) with a band gap of 1.5 eV. Hall studies and electrical analysis indicate the high quality of the CdTe films. Therefore, it can be concluded that the developed surfactant-mediated CdTe ink is highly promising for solution-processed CdTe-based photovoltaics.
关键词： spin coating,Triton X-100 surfactant,thiol-amine cosolvents,CdTe ink,CdTe thin films,photovoltaics
更新于2025-09-23 15:21:01
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[IEEE 2019 International Energy and Sustainability Conference (IESC) - Farmingdale, NY, USA (2019.10.17-2019.10.18)] 2019 International Energy and Sustainability Conference (IESC) - Metal oxide-based heterojunction thin films for solar cell applications
摘要： The interest and development in a fully green future towards sustainable technology and environmental preservation has spurred exponentially for the past few years. The adoption in clean energy is underway with solar photovoltaic (PV) technology leading the race. To keep PV sector competitive with current conventionally generated electricity, an alternative economic PV module using cheap materials with low-cost deposition method is needed. Among the candidate, metal oxides (MO) semiconductors are great potential materials to achieve this goal due to its massive availability, non-toxicity, chemically stable, and can be deposited using low-cost techniques at ambient condition. In this report, the p-n junction solar cell was fabricated using layer by layer deposition of n-type and p-type metal oxide semiconductors. Co3O4 and CuO were used as absorbing layers and ZnO as a window layer in contact with each other using simple spin coating deposition method. Photocurrent density (JSC), photo voltage (VOC) and the crystallinity of materials were investigated to characterize their optoelectronic properties. It is observed that Co3O4 shows larger crystallite size compared to CuO at 26.66 nm and 24.86 nm, respectively. Samples consisting of Co3O4 and CuO p-n junction solar cell exhibits high absorbance in the visible spectral region of 350 nm to 750 nm. J-V measurement of FTO/ZnO/Co3O4/In heterojunction films exhibits short-circuit current density of 0.391 mA/cm-1 and open-circuit voltage of 0.476 V under the illumination of AM1.5 solar simulation (100mW/cm2). Meanwhile, FTO/ZnO/CuO/In shows short-circuit current density of 0.429 mA/cm-1 and open-circuit voltage of 0.048 V. Thus, it shows that green materials without any environmental issue has high potential in solar cells application.
关键词： CuO,Co3O4,Sol-Gel,Solar Cell,Spin Coating,Heterojunction
更新于2025-09-23 15:21:01