Morphology Of CdS Nanoparticles Research Articles

Structure and Morphology of Cds Nanoparticles

The structure and morphology of CdS nanoparticles obtained by the hydrothermal synthesis are studied at temperatures of 80 °С, 100 °С, 120 °С, and 140 °С. The analysis is performed by calculating X-ray diffraction patterns by the Debye formula followed by the optimization of model parameters of nanocrystals. It is shown that with increasing temperature the CdS structure gradually transforms from a very defective sphalerite-like structure to very defective wurtzite-like one. At all temperatures the particles are ellipsoids stretched along the perpendicular to packing defects. An increase in the temperature causes a gradual enlargement of nanoparticles.

Amino acids (l-arginine and l-alanine) passivated CdS nanoparticles: Synthesis of spherical hierarchical structure and nonlinear optical properties

CdS nanoparticles (NPs) passivated with amino acids (l-alanine and l-arginine) having spherical hierarchical morphology were synthesized by room temperature wet chemical method. Synthesized NPs were characterized by ultraviolet–visible (UV–vis) spectroscopy to study the variation of band gaps with concentration of surface modifying agents. Increase in band gap has been observed with the increase in concentration of surface modifying agents and was found more prominent for CdS NPs passivated with l-alanine. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis were carried out for the study of crystal structure and morphology of CdS NPs. The average particle size of CdS NPs calculated from Debye-Scherer formula was found to less than 5 nm and agrees well with those determined from UV–vis spectra and TEM data. Fourier transform infrared (FT-IR) spectroscopy was performed to know the functional groups of the grown NPs. Peaks in FT-IR spectra indicate the formation of CdS NPs and capping with l-alanine and l-arginine. Photoluminescence spectra of these NPs were also studied. Finally, colloidal solution of CdS-PVAc was subjected to Z-scan experiment under low power cw laser illumination to characterize them for third order nonlinear optical properties. CdS-PVAc colloidal solution shows enhanced nonlinear absorption due to RSA and weak FCA on account of two photon absorption processes triggered by thermal effect.

Self-Assembled Organic–Inorganic Hybrid Nanocomposite of a Porphyrin Derivative and CdS

A porphyrin derivative, 5-(4-carboxylphenyl)-10,15,20-tris(4-chlorophenyl) porphyrin (PorCOOH), was synthesized and self-assembled as a monolayer thin solid film on the modified surface of a quartz substrate by an ester bond between –COOH groups of PorCOOH molecules and –OH groups of the hydrophilic pretreated SiO2 surface. An analysis of the spectral change revealed the J-aggregate nature of PorCOOH molecules in the obtained thin solid film. With this thin solid film of PorCOOH as a template, CdS nanoparticles were deposited on it in situ, which were further characterized by electronic absorption, fluorescence, and energy-dispersive X-ray spectroscopy. The morphology of CdS nanoparticles is disklike, and the diameter is ca. 40–60 nm, determined by scanning electronic microscopy. Furthermore, electron transfer between the organic layer and CdS nanoparticles was deduced through fluorescence quenching and theoretical analysis.

Power conversion efficiency enhancement of various size CdS quantum dots and dye co-sensitized solar cells

Various size CdS nanoparticles have been synthesized on the TiO2 nanorod arrays by chemical bath deposition method with annealing treatment at different temperatures. The size and morphology of CdS nanoparticles can be observed from scan electron microscope and transmission electron microscopy images. Based on UV–vis absorption measurement and photocurrent density-voltage characterization, the results display that compared with the device with the uniform size particles, the device with various size CdS nanoparticles shows the better performance with higher short-circuit current density, open-circuit voltage, and power conversion efficiency (PCE). Furthermore, the device sensitized by quantum dot-dye bilayer is fabricated and the PCE of the device enhances up to 2.81%, which is 1.6 times higher than that of the device sensitized by quantum dots.

Effect of pyridine as a ligand in precursor on morphology of CdS nanoparticles

[Cd(thqdtc)2], [Cd(thqdtc)2(py)] and [Cd(thqdtc)2(2,2′-bipy)] (where thqdtc=1,2,3,4-tetrahydroquinolinecarbodithioate; py=pyridine; 2,2′-bipy=2,2′-bipyridine) have been found to be effective single source precursors for the preparation of diethylenetriamine capped CdS nanoparticles via solvothermal method. Flower-like and rod-like CdS nanoparticles were prepared at a relatively low temperature by thermolysis of the precursors using chelating solvent diethylenetriamine. Use of [Cd(thqdtc)2] and [Cd(thqdtc)2(2,2′-bipy)] afforded rod-shaped nanoparticles and flower-like nanoparticles obtained from [Cd(thqdtc)2(py)]. UV–Visible spectroscopy established pronounced quantum confinement effect. X-ray diffraction (XRD) analysis revealed hexagonal crystal phase for so obtained CdS nanoparticles. The nanoparticles were also characterized by transmission electron microscopy (TEM) and fluorescence spectroscopy.

Protein‐semiconductor quantum dot hybrids for biomedical applications

AbstractThe present work reports the bioconjugation of CdS quantum dots (QDs) with protein by means of an aqueous route at room temperature, applying colloidal chemistry methods. Essentially, the bioconjugates were developed based on albumin (BSA) used as capping ligands for the stabilization of CdS QDs produced using cadmium perchlorate and thioacetamide precursors. CdS QDs were directly capped with BSA or BSA bioconjugated to polyvinyl alcohol (PVA) polymer. UV‐visible spectroscopy (UV‐vis), TEM and photoluminescence spectroscopy (PL) were used to characterize the stability and morphology of CdS nanoparticles. The CdS nanocrystals were produced with estimated average particle size smaller than 4.0 nm, indicating that they were within the so‐called “quantum‐size confinement range”. The results have clearly shown that both routes (BSA and BSA conjugates) were effective on stabilizing fluorescent QDs in aqueous dispersions to be potentially used in biomedical applications (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Photocatalytic activity of CdS nanoparticles synthesized by a facile composite molten salt method

Single-crystalline CdS nanoparticles were synthesized for the first time by the composite-molten-salt (CMS) method, with advantages of one-step, ambient pressure, low temperature, template-free and low cost. The influence of temperature, growth time and amount of salts on the morphology of CdS nanoparticles was systematically investigated. It shows that a smaller size of CdS nanoparticles can be obtained under lower temperature, less growth time and more composite salts. UV–vis reflection spectrum of the nanoparticles reveals that the nanoparticles have a bandgap of 2.34eV. Photoluminescence spectrum was also carried out to explore its optical property. Photocatalytic degradation of rhodamine B (RhB) and methylene blue (MB) in presence of the CdS nanoparticles was compared with that in presence of the commercial TiO2 nanoparticles under the simulated sunlight.

Organic/Inorganic Self-Assembled Film Based on a Perylenetetracarboxylic Diimide Derivative/CdS

A perylenetetracarboxylic diimide derivative, N,N,N′,N′-tetra(hydroxyethyl)-1,7-di (4-tert-butylphenol)perylene-3,4:9,10-tetracarboxylic diimide(THPDI), was synthesized and covalently self-assembled as a monolayer on the modified a quartz surface. UV-vis absorption and IR spectra revealed the H-aggregate nature of THPDI molecules in the obtained thin solid film. With this thin solid film as a template, CdS nanoparticles were deposited on it in situ, which were characterized by electronic absorption, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The morphology of CdS nanoparticles is disklike, and the diameter is ca. 150 nm as determined by AFM. The present result provides an effective and new method toward directed growth of specific morphologies of the nanoparticles. It is believed helpful for designing and preparing molecular-based nano-electronic and nano-optoelectronic devices with good performance.

Self-Assembled Organic−Inorganic Hybrid Nanocomposite of a Perylenetetracarboxylic Diimide Derivative and CdS

A perylenetetracarboxylic diimide derivative, N-n-hexyl-N'-(2-hydroxyethyl)-1,7-di(4'-t-butyl)phenoxy-perylene-3,4:9,10-tetracarboxylic diimide (HO-PDI), was synthesized and self-assembled as a monolayer thin solid film on the modified surface of a quartz substrate by an ester bond between -OH groups of HO-PDI molecules and -COOH groups of p-phthalic acid grafted onto the hydrophilic pretreated SiO(2) surface. An analysis of the spectral change revealed the J-aggregate nature of HO-PDI molecules in the obtained thin solid film. With this thin solid film of HO-PDI as a template, CdS nanoparticles were deposited on it in situ, which were further characterized by electronic absorption, fluorescence, and energy-dispersive X-ray spectroscopy (EDS). The morphology of CdS nanoparticles is disklike, and the diameter is ca. 140 nm as determined by atomic force microscopy (AFM). Furthermore, electron transfer between the organic layer and CdS nanoparticles was deduced through fluorescence quenching and theoretical analysis.

The Effect of Precursor Concentration, Temperature and Capping Group on the Morphology of CdS Nanoparticles

A novel ligand to the synthesis of nanoparticles has been employed in this study. A Tetramethylthiuram disulphide cadmium complex (abundant in sulphur atoms) was used as a single-source precursor for the synthesis of CdS nanoparticles. The CdS nanoparticles were synthesized under various conditions and were characterized using UV/Vis, PL, XRD and TEM. The influence of the precursor concentration, temperature and capping environment as factors affecting the morphology and size of the nanoparticles was investigated. We observed that with an increase in precursor concentration, there was an increase in particle sizes and the morphology evolved from spherical to rod-shaped nanoparticles. An increase in temperature showed only evidence of increasing the particle sizes whilst the capping environment had a profound influence on the morphology of the nanoparticles. The work reported in this paper demonstrate that factors such as temperature, concentration and the capping group affects the growth of nanoparticles either in size and/or shape.

Synthesis and characterization of CdS/multiwalled carbon nanotube heterojunctions

CdS nanoparticles were successfully immobilized on multiwalled carbon nanotubes (MWNTs)via a simple solvothermal approach using dimethyl sulfoxide (DMSO) both as medium and sulfursource. The dependences of size and morphology of CdS nanoparticles on the reaction duration,Cd2+ concentration, and medium were investigated. IR, thermogravimetry–differential scanningcalorimetry (TG–DSC), and UV–vis spectrometry were performed to understand theinteraction between CdS nanoparticles and MWNTs.

Fabrication of Organic/Inorganic Hybrid Nanocomposite of 1,8-Naphthalimide and CdS in Self-Assembly Film

A derivative of naphthalimide compounds (NAP) is synthesized in our laboratory, and a self-assembly film is fabricated through an ester bond between the −OH groups in NAP molecules and −COOH groups on modified mica. Then this film is used as a template, and CdS nanoparticles are deposited on it in situ. The morphology of CdS nanoparticles is disk-like, and the diameter is ca. 4 nm by atomic force microscopic (AFM) study. Further, electron transfer between organic films and CdS is deduced through the phenomenon of fluorescence quenching and theoretical analysis.