Formation Of CdS Nanoparticles Research Articles

ФОРМУВАННЯ ТА ВЛАСТИВОСТІ СТРУКТУРОВАНИХ ПОЛІАКРИЛАМІДНИХ ГІДРОГЕЛІВ З НАНОЧАСТИНКАМИ CdS

The new method of obtaining nanocomposite hydrogels with embedded mineral nanoparticles has been proposed. CdS nanoparticles have been synthesized in situ in hydrogel matrix based on the copolymer of acrylamide and acrylic acid under the conditions of diffusion fluxes of Cd2+ та S2- structure-forming ions. The formation of CdS nanoparticles in polymeric matrix has been approved by the methods of XRD, energy- dispersive analysis, UV-spectroscopy. The influence of the content of polymer matrix onto physico- mechanical properties of hydrogel has been studied.

Synthesis of CdS nanoparticles in water/DMF medium: an investigation on the effect of time and microwave irradiation

Nanostructured semiconductors are a pillar of the newly developed ‘artificial photosynthesis’ field of research. Cadmium sulfide is amongst the most studied semiconductors due to its suitable band structure which can utilize a sizable portion of the visible part of solar irradiation. Additionally, the band energies of this material are perfect for carrying out photochemical reactions in the aqueous medium. A wide variety of methods have been considered with the purpose of morphology engineering for this material. Herein, we report a simple yet rapid method for the synthesis of CdS nanoparticles in the realm of quantum confinement without using additives for particle growth suppression. In-situ UV–Vis spectrophotometry was used to study the formation and growth of CdS nanoparticles over time. Furthermore, the particles were characterized by XRD, XPS, DRS, FESEM, EDS, and TEM and a possible reaction mechanism has been postulated.

Structural and Morphological Characterization of CdS Nanoparticles

Aims: CdS nanoparticles are an attractive material having applications in various fields like pigment in paints, biotag for bioimaging and many more optoelectronic as well as biological applications. The present study aims to synthesize and characterize the CdS nanoparticles to make it applicable in different areas. Objectives: Preparation of CdS nanoparticles by using simple and facile chemical methods and further physical and structural characterization using various physical tools. Methods: In present work, CdS nanoparticles have been synthesized by using a rationally simple chemical precipitation method with some modification on temperature and incubation time in existed methods. Characterizations were done by employing XRD, SEM, TEM and AFM techniques. Results: Simple chemical method produces the CdS nanoparticles with a size of about 100- 200 nm in length and 5-10 nm in diameter. The SEM studies show that the CdS nanoparticles can agglomerate and form a continuous network-like structure. The X-Ray Diffraction (XRD) measurements show the single-phase formation of CdS nanoparticles with the structure of the cubic phase, and the broadening of XRD patterns indicates that the prepared samples are nanostructured. Our analysis of CdS nanoparticles by using a transmission electron microscope and Atomic Force Microscope (AFM) revealed that the nanoparticles form both spherical and nearly rod-shaped with the average size applicable for biotagging. UV-Vis spectroscopic analysis reveals a blue shift in the absorption peak probably caused by quantum confinement. Conclusion: The observed CdS nanoparticles were appeared yellow in color. The XRD pattern of the CdS nanoparticles showed that the materials were of nanometric sized regime with a predominantly cubic phase along with the rod and round morphology. The study and characterization of CdS nanoparticles will bring us a new approach to understand the biological problem by tagging nanoparticles with biomolecules and further suggest that the CdS nanoparticles formulate it more suitable biocompatible nanomaterial for biotagging and bioimaging.

Comparative transcriptome analysis uncovers roles of hydrogen sulfide for alleviating cadmium toxicity in Tetrahymena thermophila

BackgroundCadmium (Cd) is a nonessential heavy metal with potentially deleterious effects on different organisms. The organisms have evolved sophisticated defense system to alleviate heavy metal toxicity. Hydrogen sulfide (H2S) effectively alleviates heavy metal toxicity in plants and reduces oxidative stress in mammals. However, the function of H2S for alleviating heavy metal toxicity in aquatic organisms remains less clear. Tetrahymena thermophila is an important model organism to evaluate toxic contaminants in an aquatic environment. In this study, the molecular roles of exogenously H2S application were explored by RNA sequencing under Cd stress in T. thermophila.ResultsThe exposure of 30 μM Cd resulted in T. thermophila growth inhibition, cell nigrescence, and malondialdehyde (MDA) content considerably increase. However, exogenous NaHS (donor of H2S, 70 μM) significantly alleviated the Cd-induced toxicity by inhibiting Cd absorbtion, promoting CdS nanoparticles formation and improving antioxidant system. Comparative transcriptome analysis showed that the expression levels of 9152 genes changed under Cd stress (4658 upregulated and 4494 downregulated). However, only 1359 genes were differentially expressed with NaHS treatment under Cd stress (1087 upregulated and 272 downregulated). The functional categories of the differentially expressed genes (DEGs) by gene ontology (GO) revealed that the transcripts involved in the oxidation–reduction process, oxidoreductase activity, glutathione peroxidase activity, and cell redox homeostasis were the considerable enrichments between Cd stress and NaHS treatment under Cd stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that the carbon metabolism, glutathione metabolism, metabolism of xenobiotics by cytochrome P450, and ABC transporters were significantly differentially expressed components between Cd stress and NaHS treatment under Cd stress in T. thermophila. The relative expression levels of six DEGs were further confirmed through quantitative real-time polymerase chain reaction (qRT-PCR).ConclusionNaHS alleviated Cd stress mainly through inhibiting Cd absorbtion, promoting CdS nanoparticles formation, increasing oxidation resistance, and regulation of transport in free-living unicellular T. thermophila. These findings will expand our understanding for H2S functions in the freshwater protozoa.

Structural, electrical and magnetic properties of glucose-capped CdS nanoparticles

Abstract CdS nanoparticles are synthesized by a simple chemical coprecipitation technique using glucose as a capping/complexing agent and their structural, morphological, electrical and magnetic properties are studied. X-ray diffraction results reveal the pure phase formation of CdS nanoparticles along with a wurtzite structure. The interaction of the glucose with CdS nanoparticles is evident from the distinct absorption bands and peaks in the Fourier transform infrared spectra. Field effect scanning electron microscope and high resolution transmission electron microscope images depict weakly aggregated spherical nanoparticles of size ~2- 20 nm. The selective area electron diffraction pattern exhibits well-resolved diffraction rings representing the polycrystalline nature of the nanoparticles. The optical band gap has been calculated using Tauc’s plot and found to be 2.58 eV, which is higher than the band gap of the bulk phase wurtzite CdS. The existence of the excitonic peak and the blue-shift in the absorption threshold confirm the quantum confinement in the synthesized nanoparticles. The temperature dependence of d. c. conductivity is studied and observed a linear response through current-voltage characteristics. Weak ferromagnetism is also observed in the synthesized CdS nanoparticles irrespective of the diamagnetic nature of CdS in bulk form. The observation of weak ferromagnetism in the synthesized nanoparticles proposes them as a potential candidate for diluted magnetic semiconductors.

Structural, electrical and magnetic properties of glucose-capped CdS nanoparticles

Abstract CdS nanoparticles are synthesized by a simple chemical coprecipitation technique using glucose as a capping/complexing agent and their structural, morphological, electrical and magnetic properties are studied. X-ray diffraction results reveal the pure phase formation of CdS nanoparticles along with a wurtzite structure. The interaction of the glucose with CdS nanoparticles is evident from the distinct absorption bands and peaks in the Fourier transform infrared spectra. Field effect scanning electron microscope and high resolution transmission electron microscope images depict weakly aggregated spherical nanoparticles of size ~2- 20 nm. The selective area electron diffraction pattern exhibits well-resolved diffraction rings representing the polycrystalline nature of the nanoparticles. The optical band gap has been calculated using Tauc’s plot and found to be 2.58 eV, which is higher than the band gap of the bulk phase wurtzite CdS. The existence of the excitonic peak and the blue-shift in the absorption threshold confirm the quantum confinement in the synthesized nanoparticles. The temperature dependence of d. c. conductivity is studied and observed a linear response through current-voltage characteristics. Weak ferromagnetism is also observed in the synthesized CdS nanoparticles irrespective of the diamagnetic nature of CdS in bulk form. The observation of weak ferromagnetism in the synthesized nanoparticles proposes them as a potential candidate for diluted magnetic semiconductors.

Formation of cadmium sulfide nanoparticles mediates cadmium resistance and light utilization of the deep-sea bacterium Idiomarina sp. OT37-5b.

Heavy metal is one of the major factors threatening the survival of microorganisms. Here, a deep-sea bacterium designated Idiomarina sp. OT37-5b possessing strong cadmium (Cd) tolerance was isolated from a typical hydrothermal vent. Both the Cd-resistance and removal efficiency of Idiomarina sp. OT37-5b were significantly promoted by the supplement of cysteine and meanwhile large amount of CdS nanoparticles were observed. Production of H2 S from cysteine catalysed by methionine gamma-lyase was further demonstrated to contribute to the formation of CdS nanoparticles. Proteomic results showed the addition of cysteine effectively enhanced the efflux of Cd, improved the activities of reactive oxygen species scavenging enzymes, and thereby boosted the nitrogen reduction and energy production of Idiomarina sp. OT37-5b. Notably, the existence of CdS nanoparticles obviously promoted the growth of Idiomarina sp. OT37-5b when exposed to light, indicating this bacterium might grab light energy through CdS nanoparticles. Proteomic analysis revealed the expression levels of essential components for light utilization including electron transport, cytochrome complex and F-type ATPase were significantly up-regulated, which strongly suggested the formation of CdS nanoparticles promoted light utilization and energy production. Our results provide a good model to investigate the uncovered mechanisms of self-photosensitization of nonphotosynthetic bacteria for light-to-chemical production in the deep biosphere.

Bacterially-assisted recovery of cadmium and nickel as their metal sulfide nanoparticles from spent Ni–Cd battery via hydrometallurgical route

Soaring demand for technology metals (e.g., Cd, Ni) and its ever-depleting primary resources ask for alternative recovery from secondary sources. Ni–Cd battery is one such source that can abridge the gap between demand and supply of such metals. Biogenic recovery, being environmentally benign, is explored for Cd and Ni recovery to manage the menace of spent Ni–Cd battery. Studies with 20, 40 and 60 mg/L Cd2+ initial concentrations in batch mode (in triplicates) at pH 7.0 ± 0.2, 30 ± 0.5 °C and 120 rpm were conducted using sulfate-reducing bacteria for 10 days. Analysis of extracellular polymeric substance revealed that protein secretion was enhanced, thereby forming Cd-EPS binding. Biosolids were collected and freeze-dried for morphological analysis viz. FESEM/EDX, PXRD and TEM, which revealed the formation of CdS nanoparticles (JCPDS card #00-042-1411) in range of 2–6 nm. Similarly, combined effect with 5, 10 and 20 mg/L Ni2+ at 20 mg/L Cd2+ were also investigated. Furthermore, to test the efficacy for real field application, spent Ni–Cd battery was dismantled and its powder was characterized, digested with concentrated HCl at 70 °C and was fed in batch mode after cooling, wherein nanoparticles of Ni and Cd sulfides were formed that has potential as semi-conducting material.

Model for UV induced growth of semiconductor nanoparticles in polymer films

A theoretical macrokinetic model for photoinduced growth of semiconductor nanoparticles was developed with allowance for specific features of their optical properties in the near ultraviolet region. In [A. A. Smirnov et al., Optical Materials Express, 8 (2018) 1603–1612] the Polymethylmethacrylate (PMMA) film containing good soluble CdS precursors [Cd(N(SCNEt2)2)2] (TEDBCd) was irradiated by an ultraviolet light emitting diode (UV LED) with a central wavelength of 365 nm at different fixed temperatures and at different fixed intensities. The authors in situ followed the evolution of absorbance at a wavelength of 405 nm where the film is initially transparent. The corresponding photon energy is larger than the bandgap of the bulk CdS crystals. The increase in absorbance of the irradiated film at this wavelength was associated with the CdS nanoparticle growth. The main result is that at a given temperature, the effect of UV radiation on the sample is determined by the exposure (dose) rather than the light intensity and the irradiation time separately. The presented paper aims at constructing a model of the semiconductor particle growth initiated by the light-induced destruction of good soluble precursor molecules and fitting this model to the experimental data, making it possible to estimate the most important parameters of the process. The photoinduced formation of CdS nanoparticles is a complicated process that includes photo-mediated destruction of the precursor molecules followed by diffusion-assisted growth of nanoclusters. The feature of the growing semiconductor nanoparticles is that rather small particles do not absorb radiation at a particular wavelength because of the quantum confinement. The theory also takes into account the finite thickness of the sample and the nonlinear effects of radiation shielding.

Microstructural and Optical properties of Silver doped Cadmium Sulphide Nanoparticles

Abstract The nanoparticles of Ag-doped CdS have been successfully synthesized at room temperature by sol-gel method using cadmium acetate, silver nitrate and sodium sulphide as precursor materials. The structural and morphological analyses have been performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDAX). The results of structural characterizations show the formation of Ag-doped CdS nanoparticles in a single phase without any impurity. The average crystallite size of all nanoparticles was calculated by Debye−Scherrer formula which came out to be 6 nm for pure CdS and increased to 10 nm for Ag-doped CdS nanoparticles. The optical absorption of the prepared Ag-doped CdS samples was determined by UV-visible spectrophotometer in the range of 350 to 800 nm. The band gap energy for pure CdS was estimated by Tauc relationship and found to be 2.7 eV, whereas it decreased to 2.3 eV for the Ag doped CdS.

Cd2+-Doped Amorphous TiO2 Hollow Spheres for Robust and Ultrasensitive Photoelectrochemical Sensing of Hydrogen Sulfide.

Hydrogen sulfide is a highly toxic molecule to human health, but high-performance detection of it remains a challenge. Herein, we report an ultrasensitive photoelectrochemical (PEC) sensor for H2S by modifying indium tin oxide (ITO) electrodes with Cd2+-doped amorphous TiO2 hollow spheres, which are prepared by templating against colloidal silica particles followed by a cadmium-sodium cation exchange reaction. The amorphous TiO2 hollow spheres act as both the probing cation carrier and the photoelectric beacon. Upon exposure to sulfide ions, the photocurrent of the functionalized photoanode proportionately decreases in response to the formation of CdS nanoparticles. The decreased photocurrent could be attributed to the mismatching bandgap between the amorphous TiO2 and CdS nanoparticles: the photoexcited electrons and holes from amorphous TiO2 are transferred to the conduction band and valence band of CdS, respectively, and then recombined. The decrease in photocurrent is linear with the concentration of sulfide ions in the range from 1 to 10 000 pmol L-1 with a detection limit of 0.36 pmol L-1. Enabled by a unique sensitization mechanism, this PEC sensor features excellent performance in a wide linear range, high selectivity and sensitivity, high stability, and low fabrication cost.

Enhanced Photocurrent of Titania Nanotube Photoelectrode Decorated with CdS Nanoparticles

In this work, CdS/TiO2 nanotubes composite nanofilms were successfully synthesized via electrodeposition technique. TiO2 titania nanotube arrays (NTAs) are commonly used in photoelectrochemical cells as the photoelectrode due to their high surface area, excellent charge transfer between interfaces and fewer interfacial grain boundaries. The anodization technique of titanium foil was used to prepare TiO2 NTAs photoelectrode. The concentration of CdCl2 played an important role in the formation of CdS nanoparticles. Field emission scanning electron microscopy (FESEM) shows that the CdS nanoparticles were well deposited onto the outer and inner of nanotube at 40 mM of CdCl2. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analyses were executed for the determination of the composition and crystalline structure of the synthesized samples. Furthermore, the data of EDX confirms the formation of titanium and oxygen for TiO2 nanotubes and cadmium and sulfide for CdS deposits. UV–visible diffuse reflectance spectroscopy (UV-DRS) displayed that CdS nanoparticle which deposited onto TiO2 NTAs causes a red-shift into the visible region. CdS/TiO2 NTAs sample prepared at 40 mM of CdCl2 showed maximum photocurrent of 1.745 mA cm-2 while the bare TiO2 NTAs showed 0.026 mA cm-1.

On the Origin of the Large Stokes-Shift of the Emission of CdS Nanoparticles Embedded in a Phosphate Glass Matrix

XRD and TEM characterisation evidenced the formation of well-dispersed CdS nanoparticles inside a phosphate glass matrix. Optical absorption and time-resolved photoluminescence study were carried out on the prepared glass samples. Optical absorption revealed the fast character of the growth of CdS nanoparticles in this medium. Photoluminescence spectra showed only one large band with a maximum at almost 740 nm, which was associated to transitions between energy levels within the bandgap of the CdS nanoparticles. From the steady state and time-resolved measurements, it was suggested that the emission comes mainly from sulfur vacancies inside the nanocrystals and on its surface, which act as deep traps for the photogenerated electrons. The creation of such vacancies was attributed to the loss of sulfur during the glass preparation as evidenced from a chemical analysis using energy dispersive X-ray spectrometry. These traps may be also induced by the fast growth of CdS nanocrystals in this matrix or laser exposure during PL measurements. These CdS-doped glasses with an intense absorption in the UV–Vis region and a large emission band with long lifetime and a large Stokes-shift are adequate for luminescent solar concentrators, photocatalytic applications and solid-state lasers.

Enhanced Photocurrent of Titania Nanotube Photoelectrode Decorated with CdS Nanoparticles

In this work, CdS/TiO2 nanotubes composite nanofilms were successfully synthesized via electrodeposition technique. TiO2 titania nanotube arrays (NTAs) are commonly used in photoelectrochemical cells as the photoelectrode due to their high surface area, excellent charge transfer between interfaces and fewer interfacial grain boundaries. The anodization technique of titanium foil was used to prepare TiO2 NTAs photoelectrode. The concentration of CdCl2 played an important role in the formation of CdS nanoparticles. Field emission scanning electron microscopy (FESEM) shows that the CdS nanoparticles were well deposited onto the outer and inner of nanotube at 40 mM of CdCl2. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analyses were executed for the determination of the composition and crystalline structure of the synthesized samples. Furthermore, the data of EDX confirms the formation of titanium and oxygen for TiO2 nanotubes and cadmium and sulfide for CdS deposits. UV–visible diffuse reflectance spectroscopy (UV-DRS) displayed that CdS nanoparticle which deposited onto TiO2 NTAs causes a red-shift into the visible region. CdS/TiO2 NTAs sample prepared at 40 mM of CdCl2 showed maximum photocurrent of 1.745 mA cm-2 while the bare TiO2 NTAs showed 0.026 mA cm-1.

Preparation of Cadmium Sulfide/Polystyrene Nanocomposites Films Using Gamma Irradiation

In the present study we have synthesized Cadmium Sulfide/Cetyltrimethylammonium bromide (CdS/CTAB) nanoparticles + by the gamma ray irradiation method and then embedded in polystyrene polymer with different concentration (2, 5 and 10 wt%) forming CdS/PS nanocomposites using solution casting method. The as-prepared CdS/CTAB nanoparticles and CdS/PS nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), Ultraviolet/Visible (UV/Vis) absorption, high resolution scanning electron microscopy (HRSEM) and thermogravimetric analysis (TGA). The XRD results indicated the formation of CdS nanoparticles with hexagonal phase. FTIR data suggesting interaction of the alkyl ammonium head group of CTAB with the CdS nanoparticle surface. UV–Vis spectroscopy revealed that the CdS/PS nanocomposites films showed quantum confinement effect. The TGA results showed incorporation of CdS nanoparticles significantly enhance the thermal properties of PS matrix. The photoluminescence spectra of CdS/PS nanocomposites films show two emission bands arising from the presence of CdS nanoparticles.

Triangular CdS nanostructure: effect of Mn doping on photoluminescence, electron spin resonance, and magneto-optical properties

In this paper, we report synthesis and study of magneto-optic Faraday effect for dilute magnetic semiconductor nanostructure. The colloidal CdS nanocrystals were prepared via hot injection method and successfully doped with Mn2+ cations. The synthesized nanoparticles were characterized by using UV–Vis spectroscopy, X-ray diffraction, photoluminescence spectroscopy, transmission electron microscopy, and electron spin resonance spectroscopy. Systematic studies on effect of Mn2+ doping on photoluminescence, electron spin resonance, and magneto-optical properties are carried out. UV–Vis spectral analysis confirms blue shift in bandgap of CdS nanoparticles due to quantum confinement effect. The X-ray diffraction study confirms hexagonal wurtzite phase formation of CdS nanoparticles without any impurity phases. TEM analysis confirms uniform particle size, having particle size distribution around 5 nm. As-synthesized undoped CdS shows triangular-shaped nanocrystals with hexagonal structure; however, triangular shape of CdS nanoparticles is not conserved after Mn2+ doping. The photoluminescence characteristic spectra of Mn2+-doped CdS nanocrystals showed emission band at 660 nm and its intensity was found to increase with increasing Mn2+ concentration. Electron spin resonance signal, with six-line hyperfine structure splitting, confirmed doping of Mn2+ ions in CdS lattice. Magneto-optic measurements showed linear variation of Faraday rotation with respect to applied magnetic field, indicating paramagnetic behavior of Mn-doped CdS. The highest Verdet constant 24.81 deg/T cm was observed for 2% Mn-doped CdS nanocrystals, which further decreases with increasing Mn2+ concentration.

Synthesis and characterization of CdS nanoparticles decorated TiO2 matrix for an efficient N3 based dye sensitized solar cell (DSSC)

The conventional dye sensitized solar cell (DSSC) comprise of mostly the titania matrix sensitized with absorber dye molecules acting as light energy scavengers. The present investigation deals with formulating CdS–TiO2 conjugate matrix for the DSSC system using N3 dye sensitizer. TiO2 nanoparticles (NPs) were pasted on FTO glass substrate and thin film of CdS was coated on titania matrix by chemical bath deposition technique using precursors cadmium acetate and thiourea. The differential absorbance spectra of the CdS–TiO2 conjugate system shows sharp absorption edges around 345–500 nm, corresponding to band gap energies in the region 3.59 and 2.47 eV respectively, indicative of formation of two distinguishable energy region for the existence of the nano crystallites of both TiO2 and CdS. The shift in Raman bands was also observed with the incorporation of CdS in TiO2 matrix. XRD data confirms the formation of crystalline CdS nanoparticles. The FE–SEM images revealed that the TiO2 particles are spherical and monodispersed having diameter in the range 20–30 nm and embedded with CdSNPs of average particle size 10–15 nm. The performance characteristics of the synthesized films towards photovoltaic behavior were studied with the record of short circuit currents through J–V measurement using N3 absorber dye and the I−/I3 − electrolyte under 30 mW cm−2 light intensity. An effective increase of efficiency is observed with the CdS modified TiO2 matrix compared to the bare TiO2 in the DSSC system and a maximum photo-conversion efficiency of 7.5 % was obtained with the optimized dye loading. Impedance spectroscopic measurements give important information about the interfacial electron injection and recombination dynamics of the device. The incident photon-to-current conversion efficiency measurements show that both the absorbers CdS and N3 dye, contribute to the cell performance.

Influence of functionalities over polymer, trimer, dimer formation and optical properties of cadmium dithiocarbamates

Homoleptic cadmium(II) bis(dithiocarbamate) complexes having polymeric [Cd(L)2]∞ (L=C7H5O2CH2NCS2CH2C6H5 (L1), 1; C6H4NO2CH2NCS2CH2C4H3O (L2), 2; C6H4FCH2NCS2CH2C4H3O (L3), 3), trinuclear [Cd(L4)2]3 (L4=4-ClC6H4CH2NCS2CH2C4H3O, 4) and dinuclear [Cd(L5)2]2, (L5=3-ClC6H4CH2NCS2CH2C6H5, 5) structures have been synthesized and characterized by elemental analyses, spectroscopy (IR, 1H and 13C {1H} NMR and UV–Vis.) and their structures have been revealed by X-ray crystallography. In 1–3 the dithiocarbamate ligands are uniquely bonded to the Cd atoms in a μ2,κ2 S,S-chelating-bridging fashion, portraying 1D coordination polymeric structures in which the cadmium(II) ions adopt six coordinate distorted octahedral structures. In 4 the six dithiocarbamate ligands are spectacularly arranged about the Cd atoms resulting in a centrosymmetric trinuclear complex in which the central metal adopts an octahedral geometry and the terminal Cd atoms are in square pyramidal environments. Complex 5 has the well-established centrosymmetric dimeric structure in which the metal atoms have a five-coordinate trigonal bipyramidal geometry. Complexes 1–4 are rare examples of polymeric and trinuclear cadmium dithiocarbamate complexes. 1–5 show luminescent characteristics in solution and in the solid state arising from the metal perturbed intra-ligand charge transfer (ILCT) states. Their TG analyses show a single step decomposition with the formation of CdS nanoparticles, which have been examined by PXRD and HRTEM.

CdS Nanoparticles Fabricated from the Single-Source Precursor [Cd{Et2NC(S)NP(S)(OiPr)2}2]: In Depth Experimental and Theoretical Studies

Reaction of the diethylammonium salt of N-thiophosphorylated thioureate [Et2NC(S)NP(S)(OiPr)2]− (L–) with CdCl2 in aqueous ethanol leads to the complex [CdL2]. The compound crystallizes in the triclinic space group P1 with Z = 2 and the metal cation is found in a tetrahedral S2S′2 coordination environment formed by the C–S and P–S sulfur atoms. The Hirshfeld surface analysis showed that the structure of [CdL2] is dominated by H···H, S···H, and O···H contacts. According to charge and energy decomposition scheme ETS-NOCV, topological noncovalent index (NCI) and quantum theory of atoms in molecules (QTAIM) calculations, both inter- and intramolecular noncovalent C–H···S and C–H···H–C interactions are the main factors that stabilize [CdL2]. Calculated NMR data, based on the GIAO approach, are in very good agreement with experimental data. The complex [CdL2] is an efficient single-source precursor for the formation of TOPO-capped CdS nanoparticles of about 5 nm diameter with wurtzite structure (TOPO = tri-n-o...

Formation of CdS nanoparticles in the matrix of silicate glass and its optical properties

CdS nanoparticles of an average diameter of ~2.7 nm have been synthesized in silicate glass by two stage heat treatment. As was demonstrated using the methods of spectrophotometry and luminescence in the ultraviolet and visible optical ranges, semiconductor phase nuclei were formed at the first stage of thermal treatment, and they grew at the second stage. The image of the spatial distribution of CdS nanoparticles in the glass network has been obtained by computer simulation. The calculated pair distribution function revealed that the average distance between nanoparticles was ~15 nm, which appears sufficient to isolate them from each other in the dielectric matrix and to ensure reliable confinement of electrons inside each nanoparticle.