Preparation Of CdS Quantum Dots Research Articles

A Novel Method for the Preparation of CdS Quantum Dots Sensitized Solar Cells Based on Free-Standing and Through-Hole TiO2 Nanotube Arrays.

The crystallized free-standing through-hole TiO2 nanotube arrays (TNAs) membranes were fabricated by a facile method. CdS quantum dots (QDs) are assembled onto free-standing through-hole NTAs films using successive ionic layer adsorption and reaction (SILAR) process. The CdS/TNAs were easily transferred to the fluorine-doped tin oxide glass to form photoanodes after they were sensitized by modifying the traditional procedure. The morphology and crystalline phase of the TiO2 nanotubes were studied by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The cells with 5 SILAR cycles show photovoltaic conversion efficiency as high as 3.34% under simulated sunlight (AM 1.5, 100 mW x cm(-2)). Obviously, the new approach promotes the uniform distribution of CdS on the densely aligned TNAs and prevents the clogging of CdS quantum dots (QDs) at the TiO2 nanotube mouth. Such enhanced properties may be ascribed to the strong combination between CdS and TiO2, favorable for charge separation of TNAs.

Study on Preparation of CdS Quantum Dots for Dye Sensitized Solar Cells

Quantum dot sensitized solar cell (QDSSC) has a potential high efficiency as the third generation solar cell, on account of the excellent performance of quantum dots. CdS is one of the most widely used quantum dot of QDSSCs, hence the optimization of its preparation process is extremely important. CdS quantum dots prepared in aqueous or alcohol on TiO2 film by successive ionic layer adsorption and reaction (SILAR) method are investigated and alcohol is found to be better than water as the precursor solvent.

Research on the Depositon of CdS Quantum Dots on TiO<sub>2</sub> Inverse Opal

As the third generation solar cells, quantum dot sensitized solar cells (QDSSC) has received wide attention from researchers because of its high theoretical energy conversion efficiency and low production costs. The preparation of CdS quantum dots for TiO2 inverse opal based QDSSC by successive ionic layer absorption and reaction (SILAR) was investigated. The optimized number of SILAR cycle and ionic reaction time was obtained by the analysis of absorption spectra.

Hydrogel templated CdS quantum dots synthesis and their characterization

This work reports a facile method for preparation of CdS quantum dots (Q-dots), using a crosslinked hydrophilic p(AMPS) hydrogel network by absorption of Cd(II) ions and sequential precipitation with aqueous Na 2S within the network at room temperature. The TEM images revealed that prepared CdS Q-dots were distributed throughout the p(AMPS) hydrogel network and their sizes were about 5 nm. The amount of inorganic material inside p(AMPS) hydrogel was determined by TGA measurements to be 16.9% by weight. Additionally, the Cd and S amounts inside the p(AMPS) network were determined by dissolution of particles with HCl (three treatments with 3 M HCl) and by using ICP-AES (for Cd) and an elemental analyzer (for S). From UV–visible absorbance measurements, optical energy gap values of 5.1 ± 0.1 eV for p(AMPS) and 2.4 ± 0.05 eV for p(AMPS)–CdS were determined. From the fluorescence spectrum of the p(AMPS)–CdS hydrogel, the peak energy was observed at 2.30 eV. The in situ prepared Q-dots were recovered from hydrogel matrices by placing the p(AMPS)–CdS composite in purified water.

Facile preparation of cds quantum dots using hyperbranched poly(amidoamine)s with hydrophobic end-groups as nanoreactors

Hyperbranched poly(amidoamine)s with methyl ester terminals (HPAMAM) were synthesized by one-pot approach and subsequently used as nanoreactors to prepare CdS quantum dots (QDs). HPAMAM could bind Cd2+ through their internal amines, while the external methyl ester groups prevented the aggregation of polymers. After reaction with S2−, CdS QDs sequestered within individual hyperbranched polymers were obtained. The resulting CdS/HPAMAM nanocomposites were characterized by dynamic light scattering, transmission electron microscopy, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, and Fourier transform infrared spectroscopy, confirming the formation of CdS QDs with small particle size and narrow size-distribution. Furthermore, the effects of Cd2+/S2− ratio and aging time on the photoluminescence of CdS QDs were also investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Large-scale preparation of CdS quantum dots by direct thermolysis of a single-sourceprecursor

CdS quantum dots (QDs) have been synthesized on a large scale,based on the direct thermolysis of one single-source precursor,(Me4N)4[S4Cd10(SPh)16], in hexadecylamine (HDA). Transmission electron microscopy (TEM) observations showthat the CdS QDs are well-defined, nearly spherical particles. The clear lattice fringes inhigh-resolution TEM (HRTEM) images confirm the crystalline nature of the QDs. Thebroad diffraction in the x-ray diffraction (XRD) pattern and diffuse diffraction rings of theselected-area electron diffraction (SAED) pattern are typical of nanomeric-size particlesand indicative of the hexagonal phase of CdS QDs. The absorption spectra confirmquantum confinement of CdS QDs. The synthesis process for CdS QDs was investigated byultraviolet–visible (UV–vis) absorption spectroscopy. The results demonstrate that thenucleation and growth stages were separated automatically in a homogeneoussystem.