Variation Of Doping Concentration Research Articles

[formula omitted] leaves mediated combustion synthesis of Tb[formula omitted] doped Zn2V2O7 nanoparticles: Color tunable photoluminescence and electrochemical studies for display and supercapacitor applications

A new series of Tb3+ doped Zn2V2O7 (ZV) nanoparticles (NPs) at different concentration from 1 to 9 mol% was synthesized by Menthaspicata leaves extract mediated solution combustion method. On Tb3+ doping, the diffraction pattern matches well with the monoclinic crystal structure with the C2/c(2/m) space group of ZV host matrix. The surface morphology tuned from irregular shaped NPs to hexagonal shaped NPs with variation in dopant concentration. The crystallite size estimated from Scherrer’s method matches well with the transmission electron microscopy analysis. The optical band gap determined from Tauc’s plot utilizing UV–Visible absorption was tuned from 3.061 to 3.035 eV with increase in dopant concentration. Under 266 nm excitation, the emission of Tb3+ ions from Tb3+-doped ZV NPs is observed, with the intensity of emission showing sensitivity to the concentration of Tb3+ ions. The optimal doping content is determined to be 7 mol %. The CIE coordinates clearly indicates the tuning of the emission color from green to blue region with increase in dopant concentration. The average color coordinated temperature was found to be 7895 K showing the cooler appearance. Further, cyclic voltammetry analysis offers valuable insights into redox reactions, electrode kinetics, and overall electrochemical behavior, while Electrochemical Impedance Spectroscopy (EIS) provides information on ion transport kinetics. Galvanostatic Charge–Discharge (GCD) analysis revealed supercapacitance values ranging from 79.43 to 133.26 F/g at 10 mV/s with increasing dopant concentration. These findings underscore the potential of this material for use in energy storage and display technology applications.

An investigation on the impact of temperature variation over the performance of formamidinium tin iodide perovskite solar cell using SCAPS simulation

The primary goals of this project are to analyze the structure and assess the photovoltaic performance of n-i-p structured formamidinium tin iodide (FASnI3) perovskite solar cells at different operating temperatures to inspect the impact of operating temperature on device performance using a Solar Cell Capacitance Simulator (SCAPS). The simulated device structure is Au/spiro-OMeTAD/P3HT/FASnI3/PCBM/TiO2/FTO, whereas spiro-OMeTAD and TiO2 serve as the hole transport layer and electron transport layer, respectively. SCAPS simulation has been performed at 200, 300, 400, 500, and 600 K operating temperatures, and corresponding current density vs voltage (J–V) characteristics have been studied in addition to the photovoltaic metrics, such as open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), and power conversion efficiency (PCE). The thickness fluctuation and doping concentration variation of the absorber layer and the electron affinity variation and thickness variation of the Hole Transport Layer (HTL) and Electron Transport Layer (ETL) under temperature variation were also examined analytically. It has been found that there is an inverse relationship between temperature and power conversion efficiency (PCE). The extended thickness of the absorber layer enhances the PCE and JSC. Temperature variations in the thickness of the ETL and HTL have a minimal effect on the PCE and JSC of the device. At standard room temperature (300 K operating temperature), the solar cell parameters are found to be a short-circuit current density (JSC) of 17.93 mA/cm2, open-circuit voltage (VOC) of 1.06 V, fill factor (FF) of 67.46% and power conversion efficiency (PCE) of 17.93%.

Temperature and humidity effects on the acetone gas sensing of pristine and Pd-doped WO3 clusters: A transition state theory study.

The performance of pristine and Pd-doped WO3 acetone gas sensors is calculated theoretically and compared with available experimental results. Temperature, humidity, and acetone concentration variation are considered in the present work. Transition state theory calculates Gibbs free energy of transition, including its components enthalpy and entropy of transition or activation. The variation of Pd doping concentration is used to obtain the maximum response and lowest response time for the optimum performance of the gas sensor. The present theory considers the reduction of acetone gas concentration as acetone reaches its autoignition temperature. Acceptable agreement between theory and experiment is obtained. The acceptance includes the decrease of Gibbs free energy with doping percentage, variation of temperature exponent to the power twelve in the considered reactions, and reduction of response time with the increase of temperature. Density functional theory at the B3LYP level is used. 6-311G** basis set (for O atoms) and SDD (for heavy Pd and W atoms) are used to optimize the structures examined in the present work. The Gaussian 09 program and accompanying software were used to perform the current tasks.

Enhanced efficiency of bifacial perovskite solar cells using computational study

The most rapidly expanding type of solar cells are the Perovskite Solar Cells (PSCs), because of its high device performance, ease of synthesis, high open-circuit voltage, and affordability. Despite these advantages, the development of perovskite-based solar cells continues to be impeded by the issues with perovskite stability and the utilization of the hazardous heavy element lead (Pb). The study emphasizes on the bifacial structure that maintains the conventional absorber layer and electron transport layer (ETL) in the optimized PSC structure. This study employs SCAPS software for device simulation to comprehensively analyze how various parameters affect the performance of solar cells. Additionally, doping concentration variation in both ETL and HTL are explored. The simulation reveals that changing device structure from monofacial to bifacial significantly influences PSC performance, demonstrating that optimizing individual layers effectively enhances overall solar cell performance. The optimized structure achieves impressive PSC performance metrics through parametric analysis, such as voltage (VOC) of 1.18 V, fill factor (FF) of 82.24%, current density (JSC) of 27.12 mA/cm2, power conversion efficiency (PCE) of 27.90% for an incident solar spectrum from the ETL side, and power conversion efficiency (PCE) of 19.86% for an incident solar spectrum from the HTL side, the calculated bifaciality factor (BF) for this structure is 71.18%.

Effect of TCS gas flow and pre-etching on homopitaxial growth of 4H-SiC.

In this study, the epitaxial growth of 6-inch n-type 4° off-axis Si-face substrates using a horizontal hot-wall LPCVD system was investigated. The study explored the epitaxial growth under different source gas flow rates, growth pressures, and pre-etching times, with particular emphasis on their effects on epitaxial growth rate, epitaxial layer thickness uniformity, doping concentration and uniformity, and epitaxial layer surface roughness. The observation was made that the increase in source gas flow rate led to variations in dopant concentration due to different transport models between nitrogen gas and source gas. Additionally, with the increase in etching time, overetching phenomena occurred, resulting in changes in both dopant concentration and uniformity. Furthermore, the relationships between these three factors and their corresponding indicators were explained by combining the CVD growth process with the laminar flow model. These observed patterns are beneficial for further optimizing growth conditions in industrial settings, ultimately enhancing the quality of the growth process.

Effect of Co/Nd co-doping on the structural, optical, and morphological properties of ZnO nanorods grown on silicon substrate Si (100) by hydrothermal method

In this study, single-doped (cobalt (Co), neodymium (Nd)), and co-doped (Co/Nd) ZnO thin films were fabricated through the hydrothermal method on a silicon substrate (100) and investigated structural, morphological, and optical characteristics. In this work, tunable bandgap engineering of single-phase Co/Nd co-doped ZnO nanorods was reported to be controlled through variation of dopant concentrations. The concentration of neodymium varies as 4, 8, and 12 % by weight, while cobalt is fixed up to 4 %. XRD confirms the phase purity and high crystalline nature of the prepared nanorods. The physical structural parameters such as-fabricated nanorods were investigated in detail. Furthermore, Scherrer, Williamson-Hall (W–H), and size-strain plot (SSP) methods were used to investigate the crystallite size and lattice strain. The optical parameters like absorbance (A), transmittance (%T), energy bandgap (Eg), skin depth (δ), optical density (Dopt), optical conductivity (σopt), Urbach energy (Eu), and extinction coefficient (k), were investigated by UV–vis spectra. This study shows that grown films are suitable for modern optoelectronic applications.

Photoluminescence property, energy transfer mechanism, and optical thermometric behavior of bismuth-europium codoped disordered melilite-type phosphor

In the pursuit of optical thermometers, the fluorescence intensity ratio technique has aroused much interest because of the urgent need for noncontact thermometers driven by technological development. Here, an optical thermometer BaLaGa3O7:Bi3+,Eu3+ based on different thermal responses of Eu3+ and Bi3+ emissions had been reported. The structure, morphology, luminescence properties, and optical thermometric behavior were investigated by experimental data comprising X-ray diffraction patterns, microscopy, and luminescence spectroscopy. The dopants with eight oxygen ligands in the melilite-type host form emission centers. The Bi3+ singly doped, and Eu3+ singly doped phosphors can have intense blue and red emissions due to the 3P1-1S0 and 5D0-7FJ(0−4) electron transitions, respectively. In the Bi3+-Eu3+ codoped phosphors, tunable emission colors were obtained owing to Bi3+→Eu3+ energy transfer and doping concentration variation. Moreover, the intensity ratio of Bi3+ and Eu3+ emissions varied with the temperature in the range of 298 − 523 K. The relative and absolute sensitivities of the as-prepared phosphor were determined to be 0.29%K−1 and 0.20%K−1, respectively, manifesting that the prepared BaLaGa3O7:Bi3+,Eu3+ has the potential to serve as phosphors for optical thermometers.

A Simulation Study on the Performance of Double Gate Junctionless Field Effect Transistor for Doping Concentration Variation

A Simulation Study on the Performance of Double Gate Junctionless Field Effect Transistor for Doping Concentration Variation

Photometry, Centroid and Point-spread Function Measurements in the LSST Camera Focal Plane Using Artificial Stars

The Vera C. Rubin Observatory’s LSST Camera (LSSTCam) pixel response has been characterized using laboratory measurements with a grid of artificial stars. We quantify the contributions to photometry, centroid, point-spread function size, and shape measurement errors due to small anomalies in the LSSTCam CCDs. The main sources of those anomalies are quantum efficiency variations and pixel area variations induced by the amplifier segmentation boundaries and “tree-rings”—circular variations in silicon doping concentration. This laboratory study using artificial stars projected on the sensors shows overall small effects. The residual effects on point-spread function (PSF) size and shape are below 0.1%, meeting the ten-year LSST survey science requirements. However, the CCD mid-line presents distortions that can have a moderate impact on PSF measurements. This feature can be avoided by masking the affected regions. Effects of tree-rings are observed on centroids and PSFs of the artificial stars and the nature of the effect is confirmed by a study of the flat-field response. Nevertheless, further studies of the full-focal plane with stellar data should more completely probe variations and might reveal new features, e.g., wavelength-dependent effects. The results of this study can be used as a guide for the on-sky operation of LSSTCam.

Synthesis of Mg-doped TiO2 Using a Hydrothermal Method as Photoanode on Bixin-Sensitized Solar Cell

Titanium dioxide (TiO2) with magnesium (Mg) doping for dye-sensitized solar cell (DSSC) photoanode application has been synthesized. DSSC components used in this study were photosensitizer (bixin), electrolyte (), cathode (platinum), and photoanode (Mg-TiO2). This research aims to determine the characteristics of Mg-doped TiO2 photoanode with variations in dopant concentration based on the results of XRD and DR/UV-Vis analysis, as well as to determine the maximum efficiency conversion energy of DSSC using Mg-doped TiO2 and undoped TiO2 as photoanodes. The synthesis of TiO2 and Mg-TiO2 was carried out using the hydrothermal method with variations in the concentration of Mg dopant of 0, 0.5, 1, and 2% based on the molar ratio. The presenceof 2% of Mg in anatase TiO2 paste decreased the TiO2 band gap from 3.15 to 2.60 eV. Analysis results show that adding Mg dopant decreased the crystal size. Mg dopants on TiO2 could also form new energy levels, which reduced the band gap energy of TiO2. In addition, the increased concentration of Mg dopants also shifted the absorption capacity of TiO2 from the ultra-violet (UV) wavelengths region to the visible light area. The maximum energy conversion efficiency of the DSSCs with Mg-doped TiO2 photoanode of 0.5, 1, and 2% are 0.045; 0.070, and 0.172%, respectively, where these three efficiency values are higher than undoped TiO2 (0.017%). The results proved that the presence of Mg dopants on the TiO2 photoanode can increase the efficiency of DSSC.

Dynamic photoluminescent and photochromic properties of CaAl12O19:Eu, Tb: A novel phosphor for advanced dual-modal multicolor anticounterfeiting

The integration of dynamic photoluminescence and photochromism to achieve dual-modal characteristics can substantially elevate the security of anticounterfeiting measures. In this study, a novel bifunctional phosphor, namely CaAl12O19:Eu, Tb possessing dynamic photoluminescence and photochromism, is developed by the sol-gel combustion method. As the duration of exposure to 254 nm ultraviolet radiation increases, the CaAl12O19:Eu, Tb phosphors exhibit exceptional dynamic luminescent characteristics and pronounced color changes. Furthermore, this exposure results in a photochromic phenomenon on the surface of the samples, causing a shift from white to light brown. With an increase in Tb doping concentration, distinct and diverse chromatic variations easily discernible are observed by the naked eye. In addition, the mechanisms underlying the dynamic photoluminescent and photochromic characteristics are analyzed herein. Furthermore, the application of the bifunctional phosphor CaAl12O19:Eu, Tb for advanced dual-modal multicolor anticounterfeiting is explored, offering enhanced security against duplication attempts.

Enhanced luminescence and electrical conductivity of polymer ultrathin films doped with TiO2 nanoparticles

The chemical polymerization method was used to prepare nanocomposite materials of polyaniline (PANi) and Titanium dioxide (TiO2) nanoparticles. Ultrathin films were deposited by using the Langmuir Blodgett (LB) Technique. Surface Pressure vs mean molecular area isotherms of nanocomposite materials showed an increase in maximum attained surface pressure with variation in nanoparticle doping concentration. Photoluminescence (PL) spectra were taken for LB multilayers deposited on a quartz substrate, an increase in the intensity of PL peaks with increasing doping concentration of TiO2 nanoparticles. The topography of LB monolayer film under atomic force microscopy (AFM) revealed that films were uniformly and densely deposited on the substrate. Phase imaging ensured the presence of nanoparticles in the polymer matrix. Conductive atomic force microscopy (C-AFM) was used to investigate the local electrical properties of nanocomposite LB films. Current-voltage characteristics showed variation in current with changing doping concentrations of TiO2 nanocomposite in PANi matrix. The work presents new insights in analyzing uniformly deposited ultrathin films of the composites which can be probed by C-AFM to reveal local electric properties by understanding topography-current correlation at the nanoscale. The conductive data analysis could be useful for understanding the current flow through the nanostructure surface.

Influence of aluminium doping on structural and optical properties of tin oxide nanoparticles

The major mechanism for activating and regulating optical characteristics, particularly band gap, in semiconducting oxides has been theorised to be variations in dopant concentration. Nanoparticles of Sn1-xAlxO2 (x = 0.0, 0.01, 0.02, 0.03, 0.04) have been synthesized by the sol-gel method and characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), FESEM, DRS, photoluminescence (PL), Raman spectroscopy. XRD measurements revealed that all the samples crystalize in tetragonal structure which was further supported by Raman spectroscopy. As the Al content grew from 0% to 4%, it was seen that the size of the crystallites varied from 8.89 nm to 4.01 nm. Using the Tauc relation, the optical band gap was computed, and it was discovered that it decreases from 3.44 eV to 3.05 eV as the Al concentration rose. Photoluminance measurements (PL) revealed that all the samples show violet emissions. Also, it was found that 3% doped sample shows lowest PL intensity which implies that the material has profound applications in photocatalysis, lithium-ion batteries and so on. Further, it was also observed that 3% aluminium doping is the optimum concentration for tin oxide sample to be used in photocatalytic applications.

SYNTHESIS AND CHARACTERIZATION NOVEL EMERALDINE-SALT@PORANGCOMPOSITES THIN FILM:CONDUCTIVITY STUDIES

A synthesis of the emeraldine salt@porangcomposite was synthesized using the in situ chemical polymerization method to form the ES@Porang composite. Polymerization using ammonium peroxodisulphate as an initiator in the aniline oxidative polymerization process and using H2SO4 doping. The composite films were prepared with variations in dopant concentration and variations in the amount of glucomannan. Characterization of the ES@Porang composite using FTIR and conductivity testing using an LCR-meter. The optimum conductivity values ​​of the ES@Porangcomposite thin film with variations in dopant concentration and amount of glucomannan were 24.3 x 10-3, 58.2 x 10-3, and 84,3 x 10-3 S/cm respectively.

Polymorphism of garnet solid electrolytes and its implications for grain-level chemo-mechanics.

Understanding and mitigating filament formation, short-circuit and solid electrolyte fracture is necessary for advanced all-solid-state batteries. Here, we employ a coupled far-field high-energy diffraction microscopy and tomography approach for assessing the chemo-mechanical behaviour for dense, polycrystalline garnet (Li7La3Zr2O12) solid electrolytes with grain-level resolution. In situ monitoring of grain-level stress responses reveals that the failure mechanism is stochastic and affected by local microstructural heterogeneity. Coupling high-energy X-ray diffraction and far-field high-energy diffraction microscopy measurements reveals the presence of phase heterogeneity that can alter local chemo-mechanics within the bulk solid electrolyte. These local regions are proposed to be regions with the presence of a cubic polymorph of LLZO, potentially arising from local dopant concentration variation. The coupled tomography and FF-HEDM experiments are combined with transport and mechanics modelling to illustrate the degradation of polycrystalline garnet solid electrolytes. The results showcase the pathways for processing high-performing solid-state batteries.

Raman Spectroscopy Investigation on Semi-curve Woven Fabric-graphene Synthesized by the Chemical Vapor Deposition Process

Abstract: Graphene is a single layer of two-dimensional carbon atoms bound in a hexagonal lattice structure with zero band gap semiconductor. Chemical vapor deposition (CVD) is one of the most promising, inexpensive and readily ways for synthesizing monolayer pristine graphene. We have synthesized monolayer graphene shaped in semi-curve woven frabic-graphene (SWF-G) on SiO2/Si substrate. Using Raman spectroscopy, we studied the central suspended portion (i.e., 1-6) of it exerting compression (stress) to the graphene supported on the substrate. The concentration of hole impurities on either side of the central position of semi-curve woven fabric-graphene (SWF-G) is more than on its central position. The variation of such hole doping concentration results in an upshift of 2D peak position (pos(2D)) which is opposite for high electron doping even if there is no intentional control of doping. The synthesized graphene is a single-layer high-quality new structure graphene. Keywords: Semi-curve woven fabric-graphene, Raman spectroscopy, Charge impurities, Compression, Doping.

Comparative study of optical properties of ZnO Zinc Blend and Rock Salt structures, TB- mBJ and GGA approximations

Currently, the most used transparent conductive oxide (TCO) is the indium tin oxide (ITO). The need for a material that can replace this TCO comes in many studies. Among these materials, we have discussed zinc oxide (ZnO). This work is carried out using full-potential linear augmented plane wave (FP-LAPW) and implemented in the Wien2k. Since the ZnO alloy has different structures, this study aims to discuss the optoelectronic behavior of the F doped ZnO with its different phases and the doping concentration variation where the amount of F is 3.125%, 6.25% and 12.5%. in the visible light range. The comparison between the Rock Salt and Zinc Blend structures gives a starting point to be compared with the third structure which is Wurtzite. TB-mBJ was applied to compare the promising results found by the GGA approximation. Its optoelectronic properties make fluorine-doped ZnO a promising candidate for optoelectronic applications.

Tensile behavior of tetragonal zirconia micro/nano‐fibers and beams in situ tested by push‐to‐pull devices

AbstractThe tensile mechanical behavior of tetragonal zirconia micro/nano‐fibers and beams was studied with push‐to‐pull (PTP) devices equipped in an in situ nanoindenter. The small‐volume ceramics generally experienced linear elastic deformation before fracture. Polycrystalline and oligocrystalline micro/nano‐fibers exhibit a tensile strength of ∼0.9–1.4 GPa, while single‐crystal beams exhibit a much higher tensile strength (∼2.1–3.2 GPa). The tensile strength of the small‐volume zirconia is found comparable to the corresponding compressive strength, which indicates the large discrepancy between the tensile and compressive strength observed in bulk zirconia becomes insignificant at micro/nano‐scales. No martensitic transformation induced shape memory strain was detected in the zirconia fibers and beams. Further variation in dopant concentration and crystal orientation was explored for single‐crystal beams and their significance in controlling the tensile strength was discussed. Our work offers a new insight into the mechanical behavior of tetragonal zirconia‐based ceramics at small scales.

Study of variability induced by random dopant fluctuation in Fe DS-SBTFET

This paper explores the affectability of random dopant fluctuation (RDF) on the performance of Ferroelectric Dopant Segregated Schottky Barrier (Fe DS-SB) TFET by utilizing 3-D TCAD simulation. The simulation technique involves the device bifurcation into rectangular coordinates where the doping charges are placed randomly as individual and discrete dopants. Threshold voltage varies significantly due to variation in source-channel dopant concentration. The dependency of threshold voltage standard deviation on various source doping concentration has been studied. Doping variability within the channel and drain regions mainly leads to alteration in ON state current. Moreover, the impact of temperature (300 K–500 K) on switching characteristics of the proposed device has been investigated.

Green synthesis of novel lanthanum doped copper oxide nanoparticles for photocatalytic application: Correlation between experiment and COMSOL simulation

Treatment of waste water via photocatalysis is one of the most effective, economical and environment friendly process. In this study, green method (leaf extract of Citrus Medica Linn.) is used to synthesize pure and lanthanum (La)-(1,2 & 3 wt%) doped copper oxide nanoparticles (CuO-NPs). Different characterization techniques such as XRD, SEM, EDS, UV/VIS, PL and FTIR are utilized to investigate their physical, chemical, optical and structural properties. The synthesized material is used as photocatalyst for degradation of methylene blue (MB) dye. Interestingly, the La doped CuO-NPs have exhibited unique results. Variation in dopant concentration reduces the particle size (40.82 ± 0.04 nm to 31.89 ± 0.02 nm) and band gap of material shifts towards visible region (3.03 eV–2.71 eV). During photocatalysis, doping reduces the electron-hole pair recombination rate which makes it a potential photocatalyst. Maximum degradation efficiency of 84% is observed in 150 min for 2% La doped CuO-NPs which reveals that 2% La doping is optimal. Further increase in dopant concentration increases band gap, therefore, degradation efficiency drops to 75%. Simulation of this work is carried out using COMSOL Multiphysics 5.3a Licensed version. A 2D model is constructed and CuO-NPs is considered as photocatalyst in order to correlate simulated and experimental photocatalytic degradation of MB and rhodamine B (RhB) dye. Comparative analysis of rate constants revealed that the trend given by simulation is very close to the experimental observations.