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Micro-structural, optical and vibrational spectra analysis of Lead sulphide, Cadmium doped PbS and Strontium doped PbS nano-structured thin films synthesized through Successive Ionic Layer Adsorption and Reaction technique for solar cell and infrared detector sensor applications
摘要： Nanostructured skinny or thin films have captivated or fascinated the research network all over the entire world. Successive Ionic Layer Adsorption and Reaction technique is well suited for producing large area deposition and multilayer thin films especially for solar cell like Dipping time, precursor concentration and number of process cycle. In the present investigation lead Sulphide (PbS), cadmium and strontium doped PbS thin films are deposited on a glass substrate by SILAR process at room temperature to study the various morphological, structural and optical properties of them.
关键词： Cadmium doped PbS,SILAR technique,Lead sulphide,Strontium doped PbS thin films,Energy gap
更新于2025-09-11 14:15:04
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An efficient cadmium free inverted red quantum dot light emitting diodes
摘要： Here, we report an efficient inverted red indium phosphide (InP) comprised QD (InP/ZnSe/ZnS, core/shell structure) light-emitting diode (QLED) by modulating an interfacial contact between the electron transport layer and emissive InP-QDs and applying self-aging approach. The red InP-QLED with optimized interfacial contact exhibits a significant improvement in maximum external quantum efficiency and current efficiency from 4.42% to 10.2% and 4.70 cd/A to 10.8 cd/A, respectively, after 69 days of self-aging, which is an almost 2.3-fold improvement compared with the fresh device. The analysis indicates the consecutive reduction in electron injection and accumulation in the emissive QD due to changes in the conduction band minimum of ZnMgO (0.1 eV after 10 days of storage times) through a downward vacuum level shift according to the aging times. During the device aging periods, the oxygen vacancies of ZnMgO reduces, which leads to lower the conductivity of ZnMgO. As a result, the improvement of charge balance in the device with the suppression of exciton quenching at the interface of ZnMgO and InP-QD.
关键词： Cadmium-free quantum dots,charge balance,charge carrier injection layers,inverted structure,light emitting diode
更新于2025-09-11 14:15:04
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Influence of cadmium precursor concentrations on the structural, optical and electrochemical impedance properties of CdZnS thin films
摘要： Thin films of cadmium zinc sulfide (CdZnS) were deposited on microscopic glass substrates using the chemical bath deposition method and the effects of the Cd precursor concentrations on the morphological, structural and optical properties of the films were studied. The surface morphology as revealed by scanning electron microscope showed closely packed nano particles randomly spread on the surface of the glass substrates. The x-ray diffraction studies showed that the thin films were polycrystalline and the crystallite size decreased with increase in the concentration of the Cd precursor. While the optical absorbance decreased, the bandgap energy increased as the concentration of the cadmium source increased. Electrochemical studies were performed by cyclic voltammetry analysis and impedance measurements at low frequency ranges. Simulation model on the impedance model was carried out to obtain a more quantitative analysis of the data. The ternary CdZnS thin film developed in this work could be useful as window layer in solar cell fabrication.
关键词： electrochemical impedance properties,optical properties,chemical bath deposition,structural properties,CdZnS thin films,cadmium precursor concentrations
更新于2025-09-11 14:15:04
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Synthesis and characterization of Polymer/Silica/QDs fluorescent nanocomposites with potential application as printing toner
摘要： In this work cadmium telluride quantum dots (CdTeQDs) were prepared via one-pot synthesis microwave assisted. Afterwards, CdTeQDs/silica (SiO2)/nigrosine (nigro)/poly (styrene co-methyl methacrylate) (PSCMM) fluorescent nanocomposite (CSNP) powders were prepared via ultrasonic treatment and post drying at 60 ℃. The samples were characterized by UV-vis absorbance, X-Ray diffraction (XRD) and transmission electron microscopy (TEM). Finally, successful printing tests were performed on security paper at 130 ℃. These results show the potential of this nanocomposite to be used as security toner.
关键词： Cadmium Telluride,Security Toner,Nanocomposite,Quantum Dots
更新于2025-09-10 09:29:36
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Investigation of structural, optical and electrical properties of transition metal oxide semiconductor CdO ZnO nanocomposite and its effective role in the removal of water contaminants
摘要： In this technological era as the usage and development of technology is on the rise we encounter serious repercussions of pollutions in both drinking and daily usage of water. Nanocomposite of Cadmium Oxide and Zinc Oxide (CdO-ZnO) has the property of alienating the pollutants from the water. A conventional hydrothermal method was adapted for the preparation of nanocomposite of CdO-ZnO from their respective metal acetate dihydrates and NaOH. Structural and morphological analysis by electron beam diffraction technique reveals the formation of unique nanorod with spherical morphology of the synthesized particle. Williamson-Hall method was used to find the crystallite size and the lattice strain. Fourier transforms infrared (FTIR) spectroscopy further confirmed the stretching and vibration of chemical bonds of the materials. The study of electronic transitions within the material was portrayed with UV-Vis absorption spectrum and the obtained energy gap is 3.99 eV. A thorough investigation of temperature dependent electrical properties of CdO-ZnO nanocomposite was carried out in the frequency range from 50 Hz to 5 MHz. Studies revealed that the composite material is responsible for higher photocatalytic performance under the irradiation of UV photon. The high photocatalytic activity was originated from superoxide O2? radicals due to the efficient trapping of photogenerated electrons in CdO by ZnO.
关键词： Zinc Oxide,Williamson-Hall method,Photocatalytic Activity,Cadmium Oxide,Electron Beam Diffraction
更新于2025-09-10 09:29:36
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Comparative activity of aqueous dispersions of CdS nanocrystals stabilized by cationic and anionic polyelectrolytes in photocatalytic hydrogen production from water
摘要： The results of a study on the photocatalytic activity of aqueous dispersions of Ni-doped CdS nanocrystals (NCs) covered with an amphiphilic polyelectrolyte (PE) shell, i.e., a polycation (NC-PC) or polyanion (NC-PA), are presented for the first time. The H2 evolution rate measured under identical conditions served as a measure of activity. The NC-PC and NC-PA samples were characterized by similar PE content (~40%) and monomodal size distribution. According to our calculations based on the NC dimensions and lattice parameters, about one macromolecule of the PE is required to stabilize one NC. The average hydrodynamic diameter of the NC-PC was found to be 1.5 times larger than that of the NC-PA due to the difference between their chemical structures and different abilities of ionogenic groups to dissociate. The photocatalytic activity of the PE-stabilized CdS nanocrystals was significantly influenced by the type of the PE, while the H2 evolution rate depended on the reducing medium used during the process. When the medium contained Na2S or when the PE-stabilized NCs were pre-treated with Na2S, the effect of the shell type was more pronounced and the activity of NC-PA was 2 to 14 times higher than that of NC-PC.
关键词： polyelectrolytes,nanocrystals,photocatalysis,cadmium sulfide,hydrogen evolution reactions,nickel
更新于2025-09-10 09:29:36
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Two new luminescent ternary Cd(II)-MOFs by regulation of aromatic dicarboxylate ligands used as efficient dual-responsive sensors for toxic metal ions in water
摘要： Two new Cd(II) metal-organic frameworks (MOFs) formulated as [Cd(L)(atpa)]n (1) and [Cd(L)(tbta)(H2O)]n (2) [H2atpa = 2-aminoterephthalic acid, H2tbta = tetrabromoterephthalic acid, L = 1,4-bis(benzimidazol-1-yl)-2-butene] were hydrothermally synthesized. 1-2 were characterized by IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. 1 displays a 3D framework with five-fold interpenetrating dia topology. 2 holds a 2D corrugated sql layer. Both MOFs were confirmed to be dual-responsive luminescent sensors (Cu2+ and Cr2O7 2- for 1, Hg2+ and Cr2O7 2- for 2) in water through the luminescence quenching experiments. The detection limits for these species were 1.2 μM (Cu2+) and 0.29 μM (Cr2O7 2-) of 1, 0.043 μM (Hg2+) and 0.13 μM (Cr2O7 2-) of 2, respectively. The luminescence quenching mechanism was investigated.
关键词： Hydrothermal synthesis,Luminescence quenching,Semi-rigidity bis(benzimidazole),Crystal structure,Cadmium(II) MOF
更新于2025-09-10 09:29:36
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Differential Fresnel-reflection-based fiber biochemical sensor with temperature self-compensation for high-resolution measurement of Cd2+ concentration in solution
摘要： A fiber biochemical sensor system was developed to measure cadmium (Cd2+) solution based on differential temperature self-compensation, which exhibits high sensitivity in detecting Cd2+. The device only consists of a light source, three couplers, two photodetectors, and two fiber sensing ends. Utilizing the efficient adsorption of cadmium ion by allylthiourea, the sensing head was prepared. The estimated concentration resolution of 4.9 × 10?7 mol/L and the standard deviation of concentration of 4.6 × 10?6 mol/L in large temperature range are achieved. The measured data is fitted to a second-order polynomial equation with good agreement. Moreover, the differential technique of the sensor can effectively eliminate concentration errors resulting from temperature fluctuations and environment effects, and thus real-time monitoring can be obtained.
关键词： Fiber biochemical sensor,Cadmium concentration measurement,Differential temperature self-compensation
更新于2025-09-10 09:29:36
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Epitaxial processing optimization and photoluminescence spectra of CdTe thin films grown on highly dissimilar SrTiO3 (001) by molecular beam epitaxy
摘要： Single crystalline CdTe epitaxial layers (CTELs) are grown on a highly dissimilar (001) SrTiO3 (STO) by molecular beam epitaxy. The optimized growth temperature is determined to be in the range of 210 °C–270 °C. The crystalline structures of the CTELs are characterized by X-ray di?raction (XRD). The lattice parameters of the CTELs are revealed by the in-plane and out-of-plane reciprocal space mapping, electron microscopy and electron di?raction, and the epitaxial relationships between ?lm and substrate are further summarized as: (111)CdTe || (001)STO, [1?10]CdTe || [010]STO and [11?2]CdTe || [100]STO. The optimized full width at half maximum is yielded to be ~108 arcsec. The high crystalline quality and sharp interface are highlighted by the appearance of well-de?ned fringes of the XRD patterns, electron microscopy and photoluminescence spectra. Finally, the possible growth mechanisms are discussed and compliant epitaxial mechanism can well account for the epitaxial growth of the CdTe(111)/STO(001) epitaxial system. The achievement of the epitaxial growth of the CTELs on (001) STO with atomic ?atness and high-crystalline quality will avail to the potential application in photo-electric devices and the further epitaxy of the Hg1-xCdxTe-based infrared detector materials.
关键词： Photoluminescence,Cadmium telluride,Strontium titanate,Epitaxial layers,Molecular beam epitaxy,Perovskite substrate
更新于2025-09-10 09:29:36
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Pure and M-doped (M=Zn, Cu, Ni, Co) cadmium oxide nanosheets, novel adsorbents for the adsorption of ethyl benzene and ortho, meta, para xylene: a theoretical study
摘要： The electronic and structural properties investigation of pure and zinc, copper, nickel, cobalt doped cadmium oxide nanosheets (CdONS) and the adsorption of ethyl benzene (EB) and ortho- meta- para xylene (OX, MX, PX) on these nanosheets were studied by density functional theory calculations. The adsorption energy, charge transfer, energy gap, spatial distribution of HOMO and LUMO orbitals and electron density scheme of ethyl benzene and ortho, meta, para xylene molecules on pure and doped CdONS are calculated. The obtained results show that the adsorption energy value increases after doping Zn, Cu, Ni and Co atoms in oxygen substituted state, especially in NiOCdONS and CoOCdONS. The adsorption energy of EB, OX, MX and PX on NiOCdONS and CoOCdONS is about ? 260?kJ/mol whereas its value on pure CdONS is approximately ? 100?kJ/mol. In comparison with pure CdONS, the adsorption energy of the molecules on MCdCdONS, decreases except in NiCdCdONS. The adsorption energy of OX, MX and PX on NiCdCdONS is ? 263.12, ? 150.94 and ? 151.85?kJ/mol, respectively. Also, the results show that the value of energy gap increases after the adsorption of EB, OX, MX and PX on CoOCdONS, therefore, CoOCdONS can be proposed as proper adsorbent and sensor for these molecules.
关键词： Adsorption,Ethyl benzene,Xylene,Cadmium oxide nanosheet,Density functional theory
更新于2025-09-10 09:29:36