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Effect of Annealing Temperature on Structural, Morphological, Optical and Electrical Properties of Spray Deposited V2O5 Thin Films
摘要： Nanostructured vanadium pentoxide (V2O5) thin films have been deposited by a simple and cost-effective spray pyrolysis technique (SPT) at substrate temperature 300 °C and post annealed at atmospheric conditions in the temperature range from 300 °C to 500 °C at a constant rate of heating. The influence of post annealing heat treatment on the crystallization of V2O5 has been investigated. Films were characterized structurally by X-ray diffraction, morphologically by Scanning electron microscopy, optically using UV-Vis spectrophotometer, electrical characterization using Hall probe and Raman spectroscopy has been carried out for phase confirmation. X-ray diffraction analysis (XRD) revealed that, as deposited films were orthorhombic structures with a preferential orientation along (0 0 1) direction. Moreover, it was observed that crystallite size increases from 22 nm to 56 nm with increase in annealing temperature. Optical properties of these samples were studied in the wavelength range 300 – 1000 nm. Raman spectrum confirms the layered structure of V2O5 thin films. Hall Effect measurements indicate that the change in carrier concentration with increase in annealing temperature.
关键词： Raman spectroscopy,carrier density,annealing temperature,V2O5
更新于2025-11-21 11:18:25
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[Methods in Molecular Biology] BCL-2 Family Proteins Volume 1877 (Methods and Protocols) || Quantification of the Interactions Between BCL-2 Proteins by Fluorescence Correlation Spectroscopy
摘要： The proteins of the Bcl-2 family regulate apoptosis by forming a complex interaction network whose output determines whether mitochondrial outer membrane permeabilization is executed. Quanti?cation of complex formation between Bcl-2 proteins in solution and in membranes is therefore key to understand how the hierarchy of interactions controls cell death induction. Fluorescence correlation spectroscopy (FCS) is a noninvasive, nondestructive method to investigate the mobility and the association of ?uorescently labeled biomolecules that has provided useful insight into the binding af?nity of the Bcl-2 interactome. FCS is based on the detection of ?uorescence ?uctuations caused by the diffusion of individual molecules through a very tiny observation volume of the detection system. Scanning FCS (SFCS) solves some of the practical challenges of acquiring FCS in membranes and expands the application scope of the method. In this chapter, we explain the principle of FCS and describe protocols how it can be used to quantify interactions between Bcl-2 proteins in solution and in model membrane systems.
关键词： FCCS,Scanning FCCS,Bcl-xL,cBid,Bcl-2,Fluorescence correlation spectroscopy,FCS,Bax
更新于2025-11-21 11:08:18
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Superior light harnessing and charge injection kinetics utilizing mirror-like nano cuboidal ceria coupled with reduced graphene oxide in zinc oxide nanoparticle based photovoltaics
摘要： Efficiency in nanoparticle based photovoltaics is limited by optical transparency, light absorption as well as detrimental back transfer of electron at the hetero-interfaces. Three dimensional (3D) micro/nanostructures with excellent light scattering properties play pivotal role in light harvesting efficiency in DSSCs. Present study deals with the design and development of ternary hybrid photoanode utilizing high quality mirror like nano-cuboidal ceria (CeO2 NC) and 2D- reduced graphene oxide (RGO) sheets in conjunction with ZnO nanoparticle. A ～6% power conversion efficiency has been achieved for photoanode with optimized CeO2 NC loaded with 1 wt% RGO into ZnO NP. CeO2 NC owing to its size and high quality mirror like facets provides a better light harvesting by multiple interactions of incident photon with the absorber as revealed by UV–Vis diffused reflectance and IPCE analysis. 2D- RGO is proposed to act as an electron sink and provides faster electron transport pathway. Inclusion of 2D- RGO sheets yields a better charge injection kinetics (keinj ～ 2.3 × 108 s?1 for ternary, 1.1 × 108 s?1 for reference device) and collection at FTO as well as elevated recombination resistance (Rrec) and photo-induced electron life time (τe), unveiled by Electrochemical Impedance Spectroscopic (EIS) analysis corroborates a reduced reverse tunneling of photo-injected electron at ZnO/sensitizer/redox couple interface.
关键词： Diffusion,Mirror-like,Light scattering material,Reduced graphene oxide,Electrochemical impedance spectroscopy,Nano cuboidal
更新于2025-11-21 11:01:37
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AIP Conference Proceedings [Author(s) CURRENT TRENDS IN RENEWABLE AND ALTERNATE ENERGY - Guwahati, India (4–6 December 2018)] - Study of laser induced micro-structural changes in reduced graphene oxide
摘要： Graphene is a promising 2D material for solar cell and energy storage applications. Graphene based materials such as Graphene oxide (GO) are proposed as anode materials for Lithium ion batteries, transparent conducting films, electrodes in polymer based solar cells and many other applications. The present paper discusses laser induced micro structural changes in reduced GO (r-GO) thin films. GO was prepared by Modified Hummers Method, which is easy and low cost method for its large-scale production. The samples were thermally annealed at 400°C to obtain r-GO. To study the influence of laser exposure on micro structure of r-GO, the Raman spectra was recorded after exposure to different time 2, 4, 6 and 8 minutes. Two different laser intensities (95 and 159 KW/cm2) were used to do the same. A blue shift in peak positions and change in ratio of intensity were observed in D and G peaks of Raman spectra after exposure. A total Raman blue shift of about 5 cm-1 is noted in each case, which is due to increased compressive stress between the carbon-carbon bonds. The Raman data was used for calculations of residual stress, grain size and defect density, which changes in gradual pattern with increase in power density and time of exposure. From these observations, it can be concluded that r-GO thin film undergoes micro-structural changes at exposed portion, without affecting rest of the film.
关键词： Graphene,Raman Spectroscopy,Reduced Graphene Oxide,Laser Induced Changes,Graphene Oxide
更新于2025-11-21 11:01:37
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Effect of electron beam irradiation on structure, morphology, and optical properties of PVDF-HFP/PEO blend polymer electrolyte films
摘要： The effect of 8 MeV energy electron beam (EB) on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/poly-ethylene oxide (PEO) (@ w/w 90:10, PHP10) polymer blend films have been prepared and studied. The change in structure, morphology, and optical properties at 40, 80, and 120 kGy EB doses were investigated. The effect of the radiation process may responsible to occurs the degradation (chain scission) and chain link (cross linking) which are confirmed by the FT-IR analysis. The band at 1401 cm?1 corresponding to the –CH2– bending or scission mode have shifted to 1397 cm?1 after 120 kGy EB dose is due to the intermolecular interaction and the changes of the macromolecular chain by breaking of bonds with increased EB dose was observed. The XRD pattern shows decreased in the crystallinity from 60.03 to 23.42% and increased amorphousity for 120 kGy EB dose the and the surface morphology was drastically changed by decreasing the size of spherulites upon increased EB dose. The increase in optical absorption and the shifting of wavelength toward a higher end (red shift) was observed after the irradiation. The energy band gaps (Eg), and Urbach energy were estimated and they are found to be decreased, but the number of carbon atoms in a cluster of was increased with increased EB dose. The obtained results notice that the physical properties of polymer blend electrolytes can be improved by EB irradiation to use in different potential applications.
关键词： Polymer electrolyte,FESEM,UV–visible spectroscopy,Structural analysis,Electron beam irradiation
更新于2025-11-21 11:01:37
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Introducing Manganese-Doped Lead Halide Perovskite Quantum Dots: A Simple Synthesis Illustrating Optoelectronic Properties of Semiconductors
摘要： Quantum dots (QDs) are considered useful for demonstrating quantum phenomena in undergraduate laboratories due to their monodisperse size and excellent optical properties. Although doping has an increasingly important role in QD fabrication in the semiconductor field, it has rarely been discussed in the context of the undergraduate laboratory. In this work, a simple synthesis and characterization method for Mn-doped CsPbCl3 QDs for an upper-level undergraduate inorganic chemistry laboratory is reported. The Mn-doped CsPbCl3 system benefits from a simplified synthesis and straightforward characterization. This experiment introduces QD research to students and offers opportunities for instructors to discuss many important concepts in inorganic chemistry, such as energy band theory, particle-in-a-box model, electron paramagnetic resonance, ligand field theory, and nanochemistry.
关键词： Inorganic Chemistry,Crystal Field/Ligand Field Theory,EPR/ESR Spectroscopy,Upper-Division Undergraduate,Hands-On Learning/Manipulatives,Laboratory Instruction,Nanotechnology
更新于2025-11-20 15:33:11
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Photophysical features and semiconducting properties of propeller-shaped oligo(styryl)benzenes
摘要： Electronic, optical, and semiconducting properties of a series of propeller-shaped oligo(styryl)benzenes have been systematically investigated to monitor the effect of the number of styryl branches (three, four, and six) around a central benzene core. In order to clarify the relationships between their structures and properties, Density Functional Theory calculations were carried out at several levels of theory considering solvents with different polarity. Absorption and vibrational Raman spectroscopies showed that cruciform, four-branched derivatives present the most effective π-conjugation in agreement with the lowest calculated bond length alternation and bandgap. Deviations from the mirror image symmetry between absorption and fluorescence spectra were related to changes in the molecular conformation upon electronic excitation. Furthermore, in order to investigate the semiconducting behavior of oligo(styryl)benzenes, molecular structure changes and different electronic properties related to ionization processes were calculated and analyzed. Hole and electron reorganization energies were also computed to provide a first approximation on the n- or p-type character of these compounds. In some cases, electron reorganization energies comparable to common n-type semiconductors were found.
关键词： photophysical properties,Density Functional Theory,charge transport,Raman spectroscopy,oligo(styryl)benzenes,semiconducting properties
更新于2025-11-20 15:33:11
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Monitoring of polycyclic aromatic hydrocarbon contamination at four oil spill sites using fluorescence spectroscopy coupled with parallel factor-principal component analysis
摘要： Fluorescence spectroscopy analysis of oil and environmental samples collected from four oil spill incidents in Canada—a 2016 pipeline spill into the North Saskatchewan River (NSR), Saskatchewan; a 2015 train derailment in Gogama, Ontario; the 1970 sinking of the SS Arrow ship in Chedabucto Bay, Nova Scotia; and the 1970 sinking of the Irving Whale barge in the Gulf of St. Lawrence—permitted assessment of the PAH content of environmentally weathered samples. A recently developed fluorescence fingerprinting model based on excitation–emission matrix-parallel factor analysis-principal component analysis (EEM-PARAFAC-PCA) was applied to (i) evaluate the intensity of the abundant PAH groups in the samples, (ii) investigate changes in the PAH composition of environmental samples over time due to weathering, and (iii) classify the original spilled oil and environmental samples within the already established classes of the fingerprinting PCA model. The environmental sediment samples collected from the Husky Energy spill site show loss of PAHs occurring over the course of 15 months post-spill. However, the extent of weathering depends on several environmental factors rather than solely the time of weathering, the PAH loss was maximum at 15 months. There was a decrease in the PAH content of the environmental samples of Gogama spill collected 20 months post-spill. Almost all of Gogama environmental sediment samples underwent substantial weathering, making PCA classification impractical. The SS Arrow and Irving Whale samples fell within adjacent PCA groups, as they both had a similar type of spilled oil (Bunker C) with similarity in chemical composition.
关键词： EEM-PARAFAC-PCA,fluorescence spectroscopy,environmental monitoring,oil spill,PAH contamination
更新于2025-11-19 16:56:42
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Diffusion Behavior of Differently Charged Molecules in Self-Assembled Organic Nanotubes Studied Using Imaging Fluorescence Correlation Spectroscopy
摘要： The diffusion behavior of fluorescent molecules within bolaamphiphile-based organic nanotubes (ONTs) was systematically investigated using imaging fluorescence correlation spectroscopy (imaging FCS). Anionic sulforhodamine B (SRB), zwitterionic/cationic rhodamine B (RB) or cationic rhodamine 123 (R123) was loaded into ONTs having cylindrical hollow structures (ca. 10 nm in inner diameter) with amine and glucose groups on the inner and outer surfaces, respectively. Wide-field fluorescence video microscopy was used to acquire imaging FCS data for dye-doped ONTs in aqueous solutions of different ionic strengths (1 – 500 mM) at different pH (3.4 – 8.4). The diffusion behavior of these dyes was discussed on the basis of their apparent diffusion coefficients (D) that were determined by autocorrelating the time transient of fluorescence intensity at each pixel on an ONT. Molecular diffusion in the ONTs was significantly slowed by molecule-nanotube interactions, as shown by the very small D (10-1 – 10-2 μm2/s). The pH-dependence of D revealed that dye diffusion was basically controlled by electrostatic interactions associated with the protonation of the amine groups on the ONT inner surface. The pH-dependent change in D was observed over a wide pH range, possibly due to electrostatically induced variations in the pKa of the densely packed ammonium ions on the ONT inner surface. On the other hand, the influence of ionic strength on D was relatively unclear, suggesting the involvement of non-coulombic interactions with the ONTs in molecular diffusion. Importantly, individual ONTs of different lengths (1 – 5 μm) afforded similar diffusion coefficients for each type of dye at each solution condition, implying that the properties of ONTs were uniform in terms of solute loading and release. These results highlight the characteristics of molecular diffusion behavior within the ONTs, and will help in the design of organic nanotubes better suited for use as drug vehicles and contaminant adsorbents.
关键词： Electrostatic Interactions,Diffusion Behavior,Ionic Strength,pH-dependence,Imaging Fluorescence Correlation Spectroscopy,Organic Nanotubes
更新于2025-11-19 16:56:42
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A Spectroscopic Study of Tautomeric Equilibrium of Salicylideneaniline in ZSM-5 Zeolites
摘要： Salicylideneaniline (SA) sorbed in cation-exchanged M-ZSM-5 (M = H+, Li+, Na+, K+, Rb+, Cs+ and Zn2+) zeolites was studied by spectroscopic techniques assisted by quantum-chemical calculations. The nature of extra-framework cations present in the zeolite void was found to affect the spectral signature of the sorbed SA molecule that points to the shift of tautomeric equilibrium between the enol and keto forms. Small size cations, such as H+ and Li+, stabilize a cis-keto SA tautomer along with a enol one in the zeolite structure. The calculations indicate that the sorbed cis-keto tautomer may have the dipole large enough to be considered as a zwitterion. New features appearing in the spectra with the increase of the cation size were attributed to the presence of trans-keto SA tautomer, which up to now has been observed only in time-resolved spectroscopic experiments. A strong interaction of the molecule with cations in Zn-ZSM-5 zeolite results in the chelation of enol SA with the divalent Zn2+ ions. The results of the study suggest that the tautomeric equilibrium of molecules belonging to the Schiff base family can be tuned by the con?nement in the nanoporous materials via a choice of topology of zeolite framework and the nature of extra-framework cations.
关键词： spectroscopy,tautomer,DFT calculations,ZSM-5,equilibrium,salicylideneaniline,zeolite
更新于2025-11-19 16:56:35