Cadmium Doped Zinc Oxide Research Articles

Synthesis and characterization of Cadmium doped zinc oxide nanocomposites

Synthesis and characterization of Cadmium doped zinc oxide nanocomposites

Synthesis of cadmium-doped zinc oxide nanoparticles via sol–gel method for ethanol gas sensing application

Synthesis of cadmium-doped zinc oxide nanoparticles via sol–gel method for ethanol gas sensing application

Synthesis and Characterization of Cadmium Doped Zinc Oxide Nanoparticles for Visible Light Driven Catalytic Removal of MB and RhB Dye: Experimental and Computational Analysis

Synthesis and Characterization of Cadmium Doped Zinc Oxide Nanoparticles for Visible Light Driven Catalytic Removal of MB and RhB Dye: Experimental and Computational Analysis

Integration of Decay Time Analysis and Radiation Measurement for Quantum-Dot-Based Scintillator’s Characterization

In this study, we demonstrated the process of an integrated apparatus for decay time analysis and gamma radiation measurement with a liquid-scintillator-based cadmium-doped zinc oxide (CZO) nanomaterial. Generally, time-resolved photon counting is an essential analysis method in the field of precision measurement in the quantum domain. Such photon counting equipment requires a pulse laser that can be repeated quickly while having a sharp pulse width of picoseconds or femtoseconds as a light source. Time-correlated single photon counting (TCSPC) equipment, which is currently a commercial product, is inconvenient for recent development research because the scintillator size and shape are limited. Here, neodymium-doped yttrium aluminum garnet (Nd/YAG) laser TCSPC equipment was constructed to analyze the fluorescence characteristics of scintillators having various sizes and shapes. Then, a liquid scintillator added with CZO nanomaterial was prepared and the Nd/YAG laser TCSPC equipment test was performed. As a result of measuring the scintillator using the manufactured Nd/YAG laser TCSPC equipment, the non-CZO liquid scintillator was analyzed at 2.30 ns and the liquid scintillator equipped with CZO-loaded nanomaterial was analyzed at 11.95 ns. It showed an error within 5% when compared with the result of commercial TCSPC equipment. In addition, it was verified that the Nd/YAG laser TCSPC system can sufficiently measure the decay time in nanoseconds (ns). Moreover, it was presented that the Compton edge energy of Cs−137 is 477.3 keV, which hardly generates a photoelectric effect, and Compton scattering mainly occurs.

Performance improvement of UV photodetectors using Cd-doped ZnO nanostructures

The present research performed thermal decomposition to synthesize pure zinc oxide (ZnO) and cadmium-doped ZnO (ZnO:Cd) nanorods with ZnO-to-Cd weight ratios of 93:7, 95:5, and 97:3. Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy were performed, and current/voltage and current/time were measured to determine the optical, structural, and morphological characteristics of ZnO and ZnO:Cd. The XRD results suggested the hexagonal wurtzite structure of all the samples and the successful incorporation of Cd into the ZnO structures. This incorporation caused a spherical to rod-like change in the shape of the nanostructures. An intense and sharp peak was observed at 380 nm (3.26 eV) in the UV region of the PL spectra of all the samples. A UV photodetector fabricated on the basis of ZnO and ZnO:Cd nanorods with a metal–semiconductor–metal configuration showed the significant photocurrent and photosensitivity of the ZnO:Cd samples in the UV photodetection application. The sensitivity of the fabricated ZnO photodetectors with Cd percentages of 0, 3, 5, and 7% was, respectively, obtained as 110.62, 463.28, 762.40, and 920.30. The fastest photoresponse, with the rise and decay times of 2.5 and 4 s, respectively, was associated with the sample doped with 5% Cd.

Influence of isovalent Cd doping concentration and temperature on electric and dielectric properties of ZnO films

In this study, pure zinc oxide and lightly cadmium doped zinc oxide (Zn1-xCdxO; x = 0.01, 0.03, 0.05 and 0.07) films were synthesized by chemical bath deposition to mainly investigate the possible impact of isovalent (in particular Cd) doping ratio and temperature on their electric and dielectric features. X-ray diffraction patterns revealed that all produced films have a dominance of ZnO hexagonal wurtzite structure with the emergence of a minor CdO cubic phase at x ≥ 0.03, and predicted the decrease in average crystallite sizes with Cd doping. Cd content in the films was verified by energy dispersive X-ray analysis. Images of scanning electron microscopy revealed the formation of nanorods and spheres on the surface of pure ZnO film which changed to porous/agglomerative spheres with Cd doping. Then a comprehensive electric and dielectric analysis was carried out as a function of frequency in a wide temperature range (300–700 K) using two separate experimental data sets, (Z, θ) and (C, G). The results demonstrated the critical effect of temperature and Cd doping ratio on the electrical and dielectric properties of ZnO films. Among the investigated films, Zn0·97Cd0·03O film recorded highest conductivity and enhanced dielectric properties which was attributed to the equal activation of grains and grain boundaries in the film structure verified by the estimation of activation energies from impedance spectrum. However, the effect of Cd doping on electric and dielectric properties was prominent only below 500 K, beyond which the doping effect became negligible which might be correlated with the effective dominance of grain boundaries at high temperatures as was witnessed by modulus spectrum.

Effect of synthetic route on morphology of zinc oxide and cadmium doped zinc oxide nanomaterials

In the current research, zinc oxide (ZnO) and cadmium doped ZnO nanoparticles (Cd-ZnO) were synthesized by hydrothermal and ultrasonication method utilising CTAB (cetyltrimethyl ammonium bromide), a cationic surfactant. The morphology and nature of crystal lattice of synthesized ZnO and Cd-ZnO nanoparticles were screened by SEM and XRD analysis. Effect of method of synthesis and dopant on the surface morphology of ZnO nanoparticles was studied. SEM studies showed the formation of ZnO nanorods (∼30–57 nm) through hydrothermal method, and nanograins (∼37–53 nm) via ultrasonication. For Cd-ZnO a vast difference was observed in the surface topography. Among the two mentioned methods Cd-ZnO nanoflakes were obtained by ultrasonication (∼100 nm) whereas hydrothermally derived Cd-ZnO was resulted as agglomerated nanorods of about 50 to 100 nm. XRD analysis also supported the results. Hence, it was shown that both the mode of synthesis has a significant effect and process of doping has a remarkable effect on the surface morphology of the ZnO nanoparticles.

Low-temperature synthesis of cadmium-doped zinc oxide nanosheets for enhanced sensing and environmental remediation applications

In the present study, we report the effect of Cd doping on the photocatalytic and photoluminescence properties of ZnO nanoparticles. Large scale synthesis of pure and Cd-doped zinc oxide (ZnO) nanoparticles was carried out by using the facile solution route at low temperature (60 °C). The synthesized products were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) attached with energy dispersive spectroscopy (EDS), UV–visible and photoluminescence spectroscopy. The detailed analysis revealed that the synthesized nanostructures were pure and well crystalline in nature and possessed wurtzite hexagonal crystal phase. Further photocatalytic results revealed that almost complete degradation of Rhodamine B (RhB) dye (10 ppm) occurred by 0.05 g of the 10% Cd-doped ZnO nanostructure within 110 min of UV exposure. In contrast, for pure ZnO, only 50% degradation of dye occured under the same set of conditions. Moreover, the photocatalytic degradation efficiency was increased with increase in the concentration of Cd2+ ions as a dopant. The better photodegradation efficiency of samples with an increase in dopant concentration was attributed to increase in the defects and reduction in bandgap width of ZnO nanoparticles. As-synthesized material was also explored as an efficient chemical sensor for the detection of hydrazine. A comparative study revealed a sharp decrease in the limit of detection for hydrazine sensing with the increased concentration of Cd2+ ions as a dopant. The Cd-doped ZnO nanomaterial also showed enhanced magnetism as compared to pure ZnO nanoparticles.

Study the photovoltaic performance of pure and Cd-doped ZnO nanoparticles prepared by reflux method

Abstract In the present work, cadmium doped zinc oxide (Cd-ZnO) nanocrystals have been prepared by the reflux method. The effect of Cd doping on the structural, morphological, optical and photovoltaic properties has been investigated. Structural characterization by X-ray diffraction reveals that polycrystalline nature increases with increasing cadmium incorporation. The particle size shows an increasing trend with increasing cadmium impurification. The average particle size for pure ZnO is 32·19 nm and it augments to 57.94 nm for 10% Cd:ZnO. The strong preferred c-axis orientation is found due to cadmium doping and degree of polycrystallinity of the crystallites also increases with increasing Cd incorporation. Integration of cadmium was confirmed from elemental analysis using EDX. SEM technique proved that the successfully coated the surfaces of the nanostructures. The optical bandgap of the films decreases with increasing Cd dopant. The value of fundamental absorption edge is 3·24 eV for pure ZnO and it decreases to 3·18 eV for 10% Cd:ZnO. The photovoltaic performance was simultaneously enhanced with Cd doing significantly. The results showed that the described synthetic method is appropriate for the preparation of doped nanostructures with high photovoltaic results.

Temperature-dependent dielectric properties of metal-doped ZnO nanofiller reinforced PVDF nanocomposites

Here, we report on the successful fabrication of organic-inorganic composite films with poly (vinylidene fluoride) (PVDF) polymer and calcium doped zinc oxide (CaZ) and cadmium doped zinc oxide (CdZ) as two different nanofillers. The incorporation of these nanofillers resulted in increased crystalline and piezoelectric β-phase content of PVDF composites. The comparison of temperature-dependent dielectric studies showed enhanced dielectric properties of CaZ-loaded PVDF composites compared to CdZ-based PVDF composites. At 1 kHz, a maximum dielectric permittivity of 26.13 with a dielectric loss of 0.477 was obtained for 10 wt% CaZ-loaded PVDF composite film (10 CaZ-P) at 100 °C. The relaxation time of as-prepared composites showed Arrhenius behavior and lower activation energy for 10 CaZ-P composites (66.24 kJ/mol). For the 10 CaZ-P composite films, the AFM topography analysis showed higher roughness value (16.54 nm) and confirmed the lower activation energy of the same.

Solution-processible Cd-doped ZnO nanoparticles as an electron transport layer to achieve high performance polymer solar cells through improve conductivity and light transmittance

In this work, electron transport layers (ETLs) with high charge transfer ability were prepared by doping ZnO nanoparticles with different concentrations of cadmium(Cd). The inverted polymer solar cell based on PTB7-Th: PC71BM as active layer and various concentrations Cd-doped ZnO (CZO) as ETLs were fabricated. The PCE of the device with optimized Cd content in the ZnO film was about 14.7% larger than that of the pure ZnO-based cells. The cadmium-doped ZnO(CZO) is a good candidate to be used as a high-quality transparent electrode in solar cell applications.

Evolution of symmetry forbidden and silent Raman modes of cadmium doped zinc oxide films activated by swift heavy ion irradiation

Origin of evolution of Raman modes from cadmium doped zinc oxide thin films is reported under swift heavy ion irradiation by performing the systematic micro-Raman investigations at various ion fluences and energy deposited into the lattices. Films were also well characterized for their structural and morphological properties. It is reported that Raman spectra of silver irradiated films show that the E2(high) peak intensity reduces with peak broadening upon increase in ion fluences, but not completely disappeared like in case of undoped zinc oxide films. Evolution of intense A1(LO) peak was also observed along with significant softening and understood by phonon localization due to high density of defects induced by irradiation. On the other hand irradiation by oxygen ions induces relatively strong A1(TO) and B1(low) modes including the non-appearance of A1(LO) mode, which were supposed to be symmetry forbidden in back-scattering and silent modes, respectively. Thus, present study provides better experimental insights about the Raman modes for their possible implications in optoelectronic devices.

A comparative study on the electrical and dielectric properties of Al/Cd-doped ZnO/p-Si structures

We have reported on the electrical and dielectric properties of Al/CdxZn1-xO/p-Si structures. The cadmium-doped zinc oxide (CdxZn1−xO) thin films with various Cd dopants (x = 0.10, 0.20 and 0.30) were deposited on p-Si wafers via sol–gel spin coating method. The admittance (Y = Gm + iωCm) measurements were performed at 1 MHz. The C−2–V plots were used to extract the main electrical parameters such as the diffusion potential (VD), the concentration of acceptor atoms (NA), depletion region width (WD) and barrier height (ΦB). The experimental results reveal that the capacitance increases with higher Cd dopant concentration due to the presence of interfacial charges while an opposite behaviour is observed in conductance. The lower values of conductance in the sample with high Cd content can be attributed to increase in series resistance. The dielectric measurements also confirm the effect of Cd substitution in ZnO on the device performance.

Synergistic effect of ozone on cadmium doped zinc oxide nanocatalyst for the degradation of textile dyeing wastewater

Degradation of textile dyeing wastewater by nano Photocatalytic Ozonation and the synergistic effect of ozone on nanocatalyst is reported in the present study. Cadmium doped Zinc oxide (Cd–ZnO) nanocatalyst was synthesized by wet chemical method and used for the photocatalytic ozonation (PCO) process. Prepared catalyst was characterized by x-ray Diffraction (XRD), Field Emission Scanning Microscopy (FESEM) and Energy dispersive x-ray (EDAX). Degradation studies were performed in an annular photoreactor after optimizing the reaction influencing factors such as Ozone dose, pH and Cd–ZnO dosage. COD removal was 83% with 0.2 mg l−1 of the Cd–ZnO, 0.48 g h−1 of ozone at pH 7. Synergistic effect of ozone on Cd–ZnO was proved from the study of kinetics of integrated and individual processes. Integrated process (Cd–ZnO/UV/O3) showed 4.2 and 3.5 times increased rate compared to Cd–ZnO/UV and O3. Biodegradability of the treated wastewater was found to increase from 0.08 to 0.42 after nano PCO. Results support the integration of nano PCO with biological treatment for the degradation of textile dyeing wastewater as a cost effective route.

Application of cadmium-doped ZnO for the solar photocatalytic degradation of phenol

In this study, photocatalysis of phenol was studied using Cd-ZnO nanorods, which were synthesized by a hydrothermal method. The Cd-ZnO photocatalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and Fourier transform infrared (FT-IR) and UV-Vis spectroscopy. XRD patterns exhibit diffraction peaks indexed to the hexagonal wurtzite structures with the P63mc space group. SEM images showed that the average size of the Cd-ZnO nanorods was about 90 nm. Moreover, the nanorods were not agglomerated and were well-dispersed in the aqueous medium. FT-IR analysis confirmed that a surface modifier (n-butylamine) did not add any functional groups onto the Cd-ZnO nanorods. The dopant used in this study showed reduction of the bandgap energy between valence and conduction of the photocatalyst. In addition, effect of various operational parameters including type of photocatalyst, pH, initial concentration of phenol, amount of photocatalyst, and irradiation time on the photocatalytic degradation of phenol has been investigated. The highest phenol removal was achieved using 1% Cd-ZnO for 20 mg/l phenol at pH 7, 3 g/l photocatalyst, 120 min contact time, and 0.01 mole H2O2.

Impact of rGO on photocatalytic performance of Cd-doped ZnO nanostructures synthesized via a simple aqueous co-precipitation route

Zinc oxide (ZnO), cadmium-doped zinc oxide (CZO), zinc oxide/reduced graphene oxide (ZnO-rGO) and cadmium-doped zinc oxide/reduced graphene oxide (CZO-rGO) nanostructures were synthesized successfully using a simple and rapid aqueous co-precipitation method at room temperature. The structure, morphologies, composition and optical properties of these samples were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), Raman and UV–vis spectroscopy, respectively. In order to achieve a synergic effect, both Cd concentration, and impact of rGO on photocatalytic performance of Cd-doped ZnO nanostructures were investigated. The photocatalytic activities of the samples were investigated with the degradation of methylene blue (MB) under sunlight and showed excellent photocatalytic degradation performance for CZO-rGO (5% Cd) compared to the other samples. Facile and low-temperature synthesis process with the excellent degradation performance demonstrates that the CZO-rGO nanocomposites have a great potential for wastewater treatment applications.

Effect of Solvents on Cadmium-Doped Zinc Oxide Nanoparticles Synthesised by Sol-Gel Technique

In this study, a comparative investigation of the effect of two solvents on cadmium-doped zincoxide (Cd-ZnO) nanoparticles synthesized via the sol-gel method is presented and discussed. Zinc acetate was used as the precursor with ethanol and methanol as solvents, and cadmium nitrate tetrahydrate was used as the cadmium dopant source. The properties of the synthesized ZnO nanoparticles were examined by XRD, SEM, TEM,TG-DTA and UV-vis spectroscopy (UV-vis). It was found that the crystallite sizes of the ZnO nanoparticles ranged from 35 to 50nm and had spherical shapes, and that the particle size decreased with Cd doping. Consequently, absorbance spectra showed that the Cd-doped ZnO nanoparticles extended the light absorption properties of the material into the visible region. Furthermore, the ZnO nanoparticles synthesized with ethanol had a relatively smaller sizethan methanol which resulted in higher absorbance of ZnO synthesized with ethanol than methanol.

Study of Cadmium-Doped Zinc Oxide Nanocrystals with Composition and Size Dependent Band Gaps

Cadmium-doped zinc oxide nanocrystals in the quantum confinement region have been firstly synthesized by a fast and facile sonochemical method. The alloyed structure of the nanocrystals is confirmed by X-ray diffraction, transmission electron microscopy, and infrared analysis. With the increase of cadmium to zinc molar ratio from 0 to 2.0, the crystallite sizes of the samples decrease from 5.1 nm to 2.6 nm, and the band gaps of the samples show a red shift then a blue shift, and a red shift again. The variations of band gaps of the samples can be interpreted by the crystallite size and the composition. It is found that both the non-thermal equilibrium environment established in the sonochemical reaction and the coordination ability of triethylene glycol solvent play crucial roles in the current preparation.

Self-assembled flower-like microstructure in Zn 1-x Cd x O nanoparticles

The structural and optical characterization of cadmium-doped zinc oxide nanoparticles synthesized by precipitation method was studied. X-ray diffraction study confirmed the substitution of cadmium dopant without disturbing the basic wurtzite structure of zinc oxide. The average crystalline size, lattice constants and unit cell volume also increased up to 4% of cadmium doping. Energy gaps of the samples were determined from the ultraviolet-visible absorption spectrum as well as Tauc's plot which infers that the energy gap decreases with the increase of cadmium content. Fourier transformation infrared spectrum confirms the cadmium dopant through peak shifting from 485 to 563 cm−1. Photoluminescence spectrum also defines the cadmium dopant by intensity increase. The broad Raman peak at 437 cm−1 indicates that the wurtzite structure of zinc oxide is weakened by 5% cadmium doping. Field emission scanning electron microscope study also confirms the existence of particles in nanometer size and it indentifies the microstructure transformation from nanoparticles to jasmine flower-like structure on 5% cadmium doping.

Developing nanostructured, cadmium doped zinc oxide methanol sensor

Cadmium doped zinc oxide nanoparticles have been synthesized by chemical combustion of acetates of metals, nitric acid and di/triethanolamine. Thick film screen-printed sensors have been fabricated using the nano-powders. The sensor exhibits fastest response time for detection of methanol in comparison to reported metal oxide alcohol sensors when doped with 2 atomic percent Cadmium at 3000C. The Doped ZnO phases were characterized by XRD, FESEM and EDS. It was found to exist as a hexagonal system in a primitive lattice with average crystallite size of around 25 nm, bandgap of 2.7 eV and grain size less than 100 nm. The sensors were found to be selectively sensitive to 20-300ppm of methanol vapours with a response and recovery times of 4- 9 seconds and 5-10 seconds respectively.