Nanocrystalline CdS Research Articles

Synthesis of Nanocrystalline CdS:Sn Film and Study on Its Optical, Structural, and Electrical Characteristics

Synthesis of Nanocrystalline CdS:Sn Film and Study on Its Optical, Structural, and Electrical Characteristics

Effect of Multilayers CdS Nanocrystalline Thin Films on the Performance of Dye-Sensitized Solar Cells

Due to relatively low price and nontoxicity of photovoltaic (PV) systems, dye-sensitized solar cells (DSSCs) recently gained a lot of attention in terms of improving their performance and longevity. Because most of the major elements are impacted by their separate production and layering procedures, the substances in DSSCs are critical to achieving these goals. Methylene blue dye sensitizer-based solar cells were effectively constructed in this work, and DSSC performance was assessed. The morphologies of nanocrystalline CdS thin films were investigated by the FE-SEM machine, and then XRD patterns of 1 layer, 2 layers, and 3 layers of nanocrystalline CdS thin films were analyzed. The thicknesses of the prepared samples were about 391 nm, 457 nm, and 912 nm for 1, 2, and 3 layers of nanocrystalline CdS thin film, respectively. J-V characteristics of the multilayer CdS thin films have been studied under a 100 mW/cm2 sunlight source. The experimental results revealed that the highest power conversion efficiency of a 3 layer porous-nanowall CdS/MB device was about 0.47%.

Nanocrystalline CdS thin films deposited by sol-gel spin coating method: Effect of aging and doping on structural, optical, and electrical properties

This work deals with the synthesization of pristine and Fe-doped CdS nanocrystalline thin films by the sol-gel spin coating method with the freshly prepared solution (Set-A) and 24 h aged solution (Set-B). The XRD patterns of pristine and Fe-doped nanocrystalline CdS thin films (Set-A) reveal hexagonal structure and the other films of set-B exhibit cubic structure. The average crystallite size of all pristine and Fe-doped nanocrystalline CdS thin films (Set-A and Set-B) was found to be lying in the range of 4.997–17.142 nm. The particle size calculated from TEM studies was found to be 11.14 nm, 10.74 nm and 8.74 nm for pristine, 2 ml Fe doped, and 5 ml Fe doped CdS thin films. The average surface roughness of the films was found to be 0.1518 nm, 4.2216 nm, and 0.1471 nm for Fe_00, Fe_01, and Fe_05 samples of Set-A, while it was found to be 0.2055 nm, 4.839 nm and 0.1803 nm for Fe_00, Fe_01 and Fe_05 samples of Set-B respectively. PL spectra reveal the occurrence of cyan emission for both sets of samples. The band gap values for the nanocrystalline thin films (Set-A) were 2.46–2.71 eV and for Set-B were in the range of 2.47–2.75 eV, which is higher than that of bulk CdS (2.42 eV). The low-temperature resistivity of the deposited films of both sets was obtained in the range of 105 to 103 Ω cm, and also found to decrease with increasing Fe concentration in CdS.

Spectroscopic Studies of CdS Nanocrystalline Thin Films Synthesized by Sol–Gel Spin Coating Technique for Optoelectronic Application: Influence of Co-Doping

Spectroscopic Studies of CdS Nanocrystalline Thin Films Synthesized by Sol–Gel Spin Coating Technique for Optoelectronic Application: Influence of Co-Doping

Application of Synchrotron Radiation-Based Micro-Analysis on Cadmium Yellows in Pablo Picasso's Femme.

The cultural heritage community is increasingly exploring synchrotron radiation (SR) based techniques for the study of art and archaeological objects. When considering heterogeneous and complex micro-samples, such as those from paintings, the combination of different SR X-ray techniques is often exploited to overcome the intrinsic limitations and sensitivity of the single technique. Less frequently, SR X-ray analyses are combined with SR micro-photoluminescence or micro-Fourier Transform Infrared spectroscopy, which provide complementary information on the molecular composition, offering a unique integrated analysis approach. Although the spatial correlation between the maps obtained with different techniques is not straightforward due to the different volumes probed by each method, the combination of the information provides a greater understanding and insight into the paint chemistry. In this work, we discuss the advantages and disadvantages of the combination of X-ray techniques and SR-based photoluminescence through the study of two paint micro-samples taken from Pablo Picasso's Femme (1907). The painting contains two cadmium yellow paints (based on CdS): one relatively intact and one visibly degraded. SR micro-analyses demonstrated that the two Cd-yellow paints differ in terms of structure, chemical composition, and photoluminescence properties. In particular, on the basis of the combination of different SR measurements, we hypothesize that the degraded yellow is based on nanocrystalline CdS with high presence of Cd(OH)Cl. These two characteristics have enhanced the reactivity of the paint and strongly influenced its stability.

Preparation and Characterization of CdS and PbS Chalcogenides Compounds and n-CdS/p-PbS photodiode

In this study, a chemical bath deposition method (CBD) is used to synthesize CdS nanocrystalline thin films onto FTO substrate using two temperatures of 70 and 80 ºC for 1h of preparation time. PbS nanocrystalline thin films are also prepared using CBD using temperature of 35 ºC for 2h. XRD measurements confirmed that the prepared CdS and PbS thin films are polycrystalline with hexagonal phase for CdS and cubic for PbS. Scanning Electron Microscope images show increasing particles size of CdS thin films with increasing temperature of preparation and the films became more adherent on the substrates without pinholes or vacancies. Optical properties are investigated through UV-Visible Spectroscopy and found decreasing in the transmittance of prepared thin films with increasing temperature. Energy band gap calculated for CdS and PbS nanocrystalline thin films found with values higher than bulk value indicating to due to the quantum confinement effect. Photoluminescence spectra of prepared CdS nanocrystalline thin films appeared sharp emission beak at around 550 nm for all samples indicating high crystallinity. Photoresponse measurements of the fabricated photodetector showed a significant sensitivity to visible light at zero applied voltage, indicating that the fabricated device is a self-powered photodetector. The device was highly photosensitive of 16833, responsivity of 1.44 mAW−1, and a low rise/fall time of 0.284/0.298 s.

A comprehensive study of structural, optical and electrical properties of Cu doped CdS nanocrystalline thin films: for optoelectronic applications

A comprehensive study of structural, optical and electrical properties of Cu doped CdS nanocrystalline thin films: for optoelectronic applications

Improving oxygen evolution activity by constructing a perylene imide based Z-scheme heterojunction

A Z-scheme charge transfer pathway was realized at the interface of CdS/PDI heterojunction by in situ growth of nanocrystalline CdS on the surface of perylene diimide (PDI), resulting in increased photocatalytic O2 evolution activity.

Optimizing ZnO/CdS Nano Composite Controlled by Fe Doping Towards Efficiency in Water Treatment and Antimicrobial Activity

Nanocrystalline composite zinc oxide (ZnO) and CdS with Fe doping thin films grown on glass substrate by chemical method. The parameters like temperature of the solution, UV exposure, pH of solution, immersion time, immersion cycles, have been controlled and standardized for nanocrystalline film. The synthesis NPs were analyzed by X-ray diffraction (XRD). Rietveld method shows that Fe-doped composite ZnO/CdS is a single pure phase and wurtzite structure. Samples were analyzed by sophisticated various instrument like XRD, UV- Visible spectrometer, HRTEM, HRSEM and composition was analyzed by EDX attached with HRTEM. The band gap was calculated by absorption spectroscopy and found that absorption was blue-shifted. The electron structure shows that doping changes the crystal structure and transition level create better efficiency and creates octahedral symmetry. The antibacterial studies showed that the 5.0 wt% Fe-doped exhibited maximum antibacterial effect.

A systematic investigation on structural and optical properties of sol–gel spin coating fabricated CdS nanocrystalline thin films: effect of Ni doping

In the present work, we have successfully fabricated undoped and Ni-doped nanocrystalline CdS thin film on an ultrasonically cleaned glass substrate employing the sol–gel spin coating technique. The structural and spectroscopic properties of the films were investigated using XRD spectra, UV–Vis spectroscopy and photoluminescence spectra, respectively. The X-ray diffraction spectra revealed the polycrystalline nature of films with cubic structure and (111) as preferred orientation. The average crystallite size evaluated by the Debye–Scherrer formula lying in the range of 6–12 nm for the deposited films. According to UV–VIS Spectroscopy, the average transmittance of films in the visible region varies between 70–90%. The optical band gap of CdS thin film was evaluated from absorption spectra. The bandgap of the deposited films is in the range of 2.48–2.70 eV which is higher than that of bulk CdS (2.42 eV). This verifies the blue shifting in band edge of CdS nanocrystalline thin films due to the quantum confinement effect. Photoluminescence spectra of the thin film showed that the fundamental band edge emission peak centred at 485 nm also called blue band emission. It is observed that the low temperature resistivity of the films was in the range of 107–103 Ω cm and also found to decrease with increasing Ni concentration, as a result from dc two probe measurements.

Effect of Al-doping on the efficiency of chemically-deposited CdS/PbS thin film solar cells

Using chemical bath deposition in an ammonia-free system, CdS/PbS solar cells have been synthesized with different Al content in their composition and varying its absorber layer thickness. Nanocrystalline CdS thin-films with an average thickness of 140 nm were prepared and, subsequently, PbS thin-films with two different thicknesses (330 and 790 nm) were grown on the CdS. X-ray diffraction studies shows that CdS and PbS thin films have a hexagonal and cubic structure, respectively. The illuminated current/voltage characteristic curves of these p-n junctions were measured using a 300 W solar simulator at air mass 1.5, and a frequency of 50-60 Hz. It was found that Al doping decreases the conversion efficiency of the solar cells with the thinnest absorber layer, from 0.19 % to 0.05 %, and for those with thicker layers, from 0.19 % to 0.03 %.

Investigation of structural, spectral, optical and nonlinear optical properties of nanocrystal CdS: Electrodeposition and quantum mechanical studies

Nanocrystalline CdS semiconductor was synthesized by electrodeposition technique, and characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), and FTIR spectroscopic methods. XRD analysis result showed that it is a hexagonal crystal structure. SEM micrographs showed that the CdS nanocrystal is homogeneously distributed on the surface. The roughness of the CdS thin films was measured by AFM. The presence of band in the FTIR spectrum at 558 cm−1 corresponds to the stretching of CdS. CdS nanocrystals were modeled separately and calculated in the Gaussian program. Structural, spectroscopic, and nonlinear optical (NLO) properties were investigated using the DFT/Lanl2dz and semi-empirical/pm6 level. Besides, by making energy calculations, Homo, Lumo, band gap, and total state density (TDOS) were calculated. The experimental band gap was measured at 2.40 eV, while this calculated for hexagonal and cubic structure as 2.21 and 2.01 eV with semiemprical/pm6 model, 2.44 and 2.25 eV with DFT/lanl2dz level.These results support that CdS nanostructures are crystallized in hexagonal structure. With this study, the obtaining of nano structured CdS films by electrodeposition method, their structural, optical and surface properties were experimentally examined, supported by theoretical calculations, and additionally NLO properties were investigated. It has been determined that the nanocrystals obtained are suitable material for optoelectronic applications.

Modification of the junction parameters via Al doping in Ag/CdS:Al thin-film Schottky diodes for microwave sensors

In this article, it is investigated the effect of Al doping in the junction parameters of Ag/CdS:Al thin-film Schottky diodes and their electrical response to microwave irradiation. Nanocrystalline CdS:Al thin-films with thicknesses between 109 and 173 nm were prepared by chemical bath deposition and, subsequently, Ag thin-films with an average thickness of 102 nm were grown on the CdS:Al using dc sputtering. The structural, chemical, morphological and optical properties of CdS:Al and Ag films were characterized by x-ray diffraction (XRD), scanning electron microscope, atomic force microscope, energy-dispersive x-ray spectroscopy and UV-Vis spectrophotometer, respectively. Current-voltage (I − V) characteristics of Ag/CdS:Al diodes, with different Al content, were obtained at room temperature in dark conditions. XRD studies shows that CdS:Al and Ag thin-films have an hexagonal and cubic structure, respectively. Crystallite sizes decreases with Al content for CdS:Al films and were found to be in the 15–40 nm range. A decrease in the intensity of the XRD main peak of CdS:Al films is observed, caused by the inclusion of amorphous Al2O3 on the CdS film. It was found that band gap of CdS:Al films increases with increasing Al content, from 2.28 eV to 2.40 eV. Based on the I − V characteristics of the diodes, their barrier height ϕ 0, ideality factor n, and series resistance R s were calculated, and it was found that these values are modified by increasing Al content in CdS films, in the ranges: ϕ 0: 0.7037–0.8426 eV; n: 3.485–4.213; R s : 0.54–9.86 MΩ. Besides, it was stated that Al doping changes the average surface roughness and the energies of the charge neutrality levels of CdS:Al films. The effects of physical properties of the films on the junction parameters of the diodes were also discussed. Finally, I − V characteristics of the Ag/CdS:Al diodes were studied under X-band microwave irradiation at room temperature in dark conditions. For a specific Al doping value, the current density across the diode during irradiation was found to be lower (0.87–11.6 mA cm−2) than unirradiated diode (1.14–15.6 mA cm−2), when the bias voltage was higher than certain value (3 V), due to an increasing temperature of the diode and the presence of Al2O3 on the CdS:Al film. This last result could be useful in a potential X-band thin-film microwave sensor.

Optical and structural of Nanocrystalline CdS

Nanocrystalline CdS thin films have been deposited using precursors with different thiourea concentration onto glass substrates by sol-gel spin coating method. The crystalline nature of the films has been observed to be strongly dependent on thiourea concentration and annealing temperature. The CdS films are found to be nanocrystalline in nature with hexagonal structure. The grain size is found to be in the range of 7.6 to11.5 nm depending on the thiourea concentration and annealing temperature. The high-resolution transmission electron microscopy (HRTEM) results of the CdS films prepared using cadmium to thiourea molar ratio of 0.3:0.3 indicate the formation of nanocrystalline CdS with grain size of 5 nm. Fourier transform infrared (FTIR) analysis shows the absorption bands corresponding to Cd and S. The optical study carried out to determine the band gap of the nanostructured CdS thin films shows a strong blue shift. The band gap energy has been observed to lie in the range of 3.97 to 3.62 eV following closely the quantum confinement dependence of energy on crystallite radius. The dependence of band gap of the CdS films on the annealing temperature and thiourea concentration has also been studied. The photoluminescence (PL) spectra display two main emission peaks corresponding to the blue and green emissions of CdS.

Bandgap engineering of low-temperature CdS nanocrystalline prepared on Si(1 1 1) without post-thermal annealing

This article reports a new attempt for the bandgap formation of cadmium sulfide nanocrystals (CdS NCs) synthesized on Si(1 1 1) substrates at low temperatures: 50 and 150 °C. The influence of energy gap alteration on the optoelectronic properties was extensively considered with the aid of various tools. A wurtzite-–hexagonal structure in both CdS/Si NCs samples was confirmed by X-ray diffraction measurements. For a crystallite size around 7 nm, wider energy gaps (2.94–2.98 eV) were revealed by photoluminescence spectra. These values are in good conformity with the precise energy gaps, 2.95 eV and 3.04 eV which were estimated using a reflection-electron energy loss spectroscopy. Consequently, such expansion in the energy bandgap indicates the occurrence of a blue shift compared to the bulk CdS. Moreover, the Raman spectra show three peaks referring to the first-, second-, and third-order scattering of the longitudinal optical phonon modes. The findings demonstrate the improved crystalline quality of the sample prepared at 150 °C with no need for further thermal annealing. It is thus inferred that quantum confinement is possible in the CdS NCs prepared at low temperatures using a pulsed-laser deposition technique; thereby, they are useful for optoelectronic applications.

Enhancement in Visible Light Photoresponse of CdS Thin Films by Nitrocellulose Surface Passivation

Herein, we demonstrated a surface-passivated Ag/CdS/Ag photodetector device fabricated using nanocrystalline CdS thin films deposited via the spray pyrolysis method. Surface passivation with nitroc...

Vital role of Ar ambient pressure in controlled properties of nanocrystalline CdS thin films

A report on the manipulation of structural, optical, and electrical properties of nanocrystalline CdS (ncCdS) thin films in the framework of varying Ar ambient pressure in pulsed laser deposition (PLD) is presented here. Increase in Ar ambient pressure results in reduction of crystallite size which in turns increases the structural imperfections and structural phase transformation of ncCdS thin films. The most significant observation here is the bleaching of multiphonon Raman modes (MRMs) particularly LO + 2E2, 2LO + 2E2, etc. in ncCdS thin films. An acute investigation on the reason of bleaching of LO + 2E2, 2LO + 2E2, etc. modes is carried out here and concluded that it is due to the fading of E2 mode with increasing Ar pressure as confirmed by low-frequency micro-Raman measurements. UV–visible absorption and photoluminescence spectroscopies are used to examine the optical properties like bandgap and possible electronic transitions in ncCdS thin films. Further, transport properties of ncCdS thin films are investigated using Hall measurement and I–V characteristics.

In situ self-assembly of 3D hierarchical 2D/2D CdS/g-C3N4 hereojunction with excellent photocatalytic performance

A novel hierarchical 2D/2D CdS/g-C3N4 hybridarchitecture was synthesized via a hydrothermal method and then characterized by XRD, FTIR, SEM, EDS, UV–vis DRS, PL, BET, and EIS. The results showed the combination of CdS and g-C3N4 changed the growth orientation of dendritic CdS nanocrystallines and promoted the high degree of exfoliation of g-C3N4, which provided the close nanosheet/nanosheet 2D/2D contact interface and large specific surface area, resulting in the effective separation of the photo-generated carrier pairs. The photocatalytic activity of CdS/g-C3N4 was 6.93 and 3.64 times higher than that of the pure g-C3N4 and CdS samples, respectively, in the degradation of RhB under visible light irradiation. The CdS/g-C3N4 showed no obvious loss of the photocatalytic activity and little change of structure after three repeated runs, which is vital in the application of photocatalyst. This could be contributed to the reinforced hierarchical 3D architecture constructed through the dendritic CdS nanosheet penetrating into g-C3N4 interlayers. The possible mechanism for formation and photocatatlytic activity of the CdS/g-C3N4 architecture was proposed.

The First Recyclable, Nanocrystalline CdS Thin Film Mediated Eco‐benign Synthesis Of Hantzsch 1, 4 Dihyropyridines, 1, 8‐Dioxodecahydroacridine and Polyhydroquinolines derivatives

In the present study, we report a recyclable, nanocrystalline CdS thin film mediated efficient one‐pot, three component synthesis of Hantzsch 1, 4 Dihydropyridine in good yields. The catalyst is also effective for the efficient synthesis of Polyhydroquinoline and 1, 8‐dioxodecahydroacridine derivatives in good to excellent yields. The CdS thin film catalyst was prepared by chemical bath deposition (CBD) technique. The cadmium sulphide thin film was characterized by powder XRD and FT‐IR studies. The average crystallite size (D) was calculated from powder XRD by using Scherrer formula and SEM analysis. The elemental composition of the CdS thin film was established by EDS analysis. The effect of temperature, substituent's, catalyst loading and mole ratio on the reaction was also studied. All the products were thoroughly characterized by 1H‐NMR, 13C‐NMR, FT‐IR, Mass spectral and CHN analysis. A plausible mechanism for the CdS thin film catalyzed synthesis of 1, 4 DHP's is proposed. The heterogeneous catalyst could be easily recovered from the reaction mixture and successively reused at least five times without loss of activity.

Photocatalytic Activity of Pure and Nickel Doped Cadmium Sulphide Nanoparticles Synthesized via Co-Precipitation Method

Cadmium sulfide is an important group of II-VI semiconducting nanomaterials with excellent physical properties and wide bandgap energy, are successful in the utilization of photocatalytic application. Photo technology is one of important technology to solve environmental and energy issues. Incorporating a transition metal ion dopant into CdS nanocrystalline is a convenient way to tailor its physical properties. In this present work, we have synthesized transition metal ion - nickel doped CdS nanocrystals via co-precipitation method. The objective of this research is to investigate the photocatalytic activity of pure and nickel doped CdS nanocrystals for the degradation of methylene blue and to provide an experimental base for further study and practical application in textile effluent and wastewater treatment processes. Many factors can influence the performance of photocatalytic activity such as phase composition, crystallite size, morphology, and energy gap. The structural and optical properties of as-synthesized materials were studied by XRD, EDAX, SEM, UV, PL, and FTIR. Photocatalytic degradation of methylene blue was performed by using nickel doped CdS nanoparticles in a photoreactor vessel irradiated by visible light from the tungsten lamp (λmax=400 nm).