Phosphors, Up Conversion Nano Particles, Quantum Dots and Their Applications

2017 ◽  
Keyword(s):  
Quantum Dots ◽  
Nano Particles

Investigation of Factors Induced the Non-Intrinsic Optical Properties for Water-Soluble CdSe Semiconductor Quantum Dots

2010 ◽  
Vol 663-665 ◽  
pp. 437-440
Author(s):  
Heng Kang Qiu ◽  
Yue Shen ◽  
Lin Jun Wang ◽  
Jian Cheng Zhang ◽  
Kai Feng Qin
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Semiconductor Quantum Dots ◽  
Water Soluble ◽  
Nano Particles ◽  
Crystal Nucleation ◽  
Band Edge ◽  
Molar Ratio ◽  
X Ray

For the purpose of investigating the factors induced the non-band-edge excitation optical properties of water-soluble CdSe semiconductor quantum dots (QDs), the initial molar ratio of Cd and Se(or Cd/Se), the temperature of crystal nucleation and growing, the time of the growth etc. are systematically studied in the fabricated process. The properties of the as-prepared nano-particles (NPs) have been characterized by ultraviolet-visible absorption spectra (UV-Vis), photoluminescence (PL) spectroscopy, X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The measured results show that it is possible to exist surface trapping, impurities and other defect energy states in the products with the non-band-edge excitation PL properties, and all the characteristics are involved with the different synthetic routes and prepared techniques.

Water photoreduction with Cu2O quantum dots on TiO2 nano-particles

2005 ◽  
Vol 171 (3) ◽  
pp. 257-259 ◽  
Author(s):  
M.K.I. Senevirathna ◽  
P.K.D.D.P. Pitigala ◽  
K. Tennakone
Keyword(s):  
Quantum Dots ◽  
Nano Particles

Biocompatible Polymeric Nanoparticles and Films Containing Hydrophobic Quantum Dots

2006 ◽  
Vol 950 ◽  
Author(s):  
Jisook Lee ◽  
Ick Chan Kwon ◽  
Kyoungja Woo ◽  
Hesson Chung
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Tumor Cells ◽  
Polymeric Nanoparticles ◽  
Aqueous Media ◽  
Nano Particles ◽  
Film Casting ◽  
Biological Applications ◽  
Stable Particles ◽  
Nih 3T3

ABSTRACTMicro- or nano-particles encapsulating hydrophobic quantum dots were prepared by the emulsion technique. Films containing quantum dots were also prepared by film casting methods. Quantum dots without hydrophilic coating were directly mixed with polymer solution to prepared extremely stable films or particles that do not phase-separate with time. The surface of the particles or films could be modified to have different hydrophilicity and/or functional groups. Particles with 1.5 ± 0.16 μm and 320 ± 26 nm in diameters and films of 300 μm in thickness were prepared. NIH 3T3 and EMT-6 were culture on the films containing quantum dots for 8 – 20 h. Compared to the control, quantum dot were delivered directly and efficiently into the cells without toxicity. When implanted near tumor cells in Balb/C mice, quantum dots migrated from the films into the tumor cells for at least 3 days. Considering that the quantum dot dispersion in aqueous media is relatively unstable and difficult to handle, our stable particles or films containing hydrophobic quantum dots can become versatile probes for biological applications.

CHARACTERIZATION OF SEMICONDUCTOR QUANTUM DOTS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4363-4372 ◽  
Author(s):  
J. N. WANG ◽  
C. L. YANG ◽  
S. H. WANG ◽  
L. GUO ◽  
S. H. YANG ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Emission Band ◽  
Green Emission ◽  
Semiconductor Quantum Dots ◽  
Nano Particles ◽  
Time Resolved ◽  
Pl Spectra ◽  
Green Emission Band ◽  
Uv Emission ◽  
Zno Qds

The applications of various optical and electrical characterization techniques to the study of semiconductor quantum dots (QDs) are summarized. Photoconductivity enhancement effect in CdS-PVK nanocomposite is studied by optical absorption, photoluminescence (PL), photoconductivity spectroscopy, and time-resolved PL. It is found that the photoconductivity of the composite is greatly enhanced in comparison with that of a simple mixture of CdS nano-particles and PVK. PL spectra have shown that luminescence from PVK is dramatically quenched by the incorporation of a low density of CdS particles. Time-resolved spectra reveal that the decay of the PL from the dots of the composite in much longer than that in the simple mixture. These have been attributed to a fast carrier transfer mechanism between CdS QDs and PVK matrix. In addition, optical properties of PVP-capped ZnO QDs are investigated in details. Typical PL spectra of PVP-capped ZnO QDs consist of a sharp UV peak located at about 3.45 eV and a broad green emission band centered at 2.34 eV. At certain Zn 2+/ PVP ratios the green emission band is quenched and only strong UV emission remains. This effect is attributed to the surface modification of ZnO quantum dots with PVP. We are able to associate the UV emission from ZnO QDs to localized states by applying temperature and excitation power dependent PL. Finally, the electronic level of molecular beam epitaxy grown self-organized ZnSe QDs embedded in ZnS is determined by applying PL, capacitance-voltage measurement, and deep level transient spectroscopy.

scholarly journals Gold Nanowires: Their Synthesis and Surface Plasmon Resonances

2009 ◽  
Vol 8 (2 and 3) ◽  
Author(s):  
Ali Faghih ◽  
Edo Waks
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Indium Arsenide ◽  
Plasmon Resonance ◽  
Nano Particles ◽  
Gold Nanowires ◽  
Plasmon Resonances ◽  
Growth Method ◽  
Nano Rods ◽  
Nano Wires

The objective of the project was to fabricate gold nano-rods and study the optical properties of gold nano-particles when coupled to Indium Arsenide quantum dots. The gold nano-rods were synthesized by a seed-mediated growth method using CTAB and BDAC as the surfactants, and the feasibility of changing the aspect ratio of the rods and their Plasmon resonance frequency was studied by varying the concentrations of these two surfactants. Finally, gold nano-rods with longitudinal Plasmon resonance of 940 nm were synthesized. Next, we studied the feasibility of coupling gold nano-wires to indium arsenide quantum dots for investigating their optical properties and studying the spontaneous emission enhancement of InAs QDs in the presence of the plasmon resonances of gold nano-wires. The sample containing nano-wires coupled to quantum dots was excited by red laser, and the emission was passed through a spectrometer and the spectrum was obtained.

scholarly journals Quantum dot solar cells for future electric prospects - A small Review

2021 ◽  
pp. 494-498
Author(s):  
Kapivardhan Y ◽  
Ramaiah V ◽  
Srinivas K
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Quantum Dot ◽  
Low Cost ◽  
Cadmium Sulphide ◽  
Nano Particles ◽  
Metallic Oxide ◽  
Quantum Dot Solar Cells ◽  
Electro Optic ◽  
Conversion Efficiencies

Owing to their versatile electro-optic properties semiconductor quantum dots (QDs) are gaining greater attention towards photovoltaic applications. Although hybrid solar cells, which are obtained by the blend of carbon-based and inorganic resources have the probable to attain higher energy conversion efficiencies, the current efficiencies are stumpy. Strategy aspects especially the electronic structure of the inanimate materials which are used as the electronic acceptors in mixture solar cells plays an important role in providing good performance. Among the four major inorganic material types which were scrutinized namely cadmium mixtures, silicon, metallic oxide nano particles besides short band gap nanoparticles, Cadmium Sulphide (CdS) quantum dots are having higher (>4%) power conversion efficiencies. As far as the academic and industrial communities are concerned, dye -sensitized solar cell has attained high priority in accordance with its good efficiencies, ease in manufacturing, low cost etc., Despite the above-mentioned advantages or the positive characteristics of vivid solar cells, the heed is towards the solar cells through extremely tinny absorber, solar cells by quantum dots absorber coatings. In accordance with which we have discussed about the quantum dot solar cells keeping electrical parameters as the highest priority. Herein we present some small review on recent studies in QD solar cells considering their electrical and impedance properties, effect of incorporation of nano materials in solar cells.

scholarly journals Nanotechnologies for the Future

2016 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Quantum Dots ◽  
Titanium Dioxide ◽  
New World ◽  
Nano Particles ◽  
Surface Level ◽  
The World ◽  
The Future ◽  
Carbon Nano Tubes ◽  
Redundant Systems

The needs of the world are growing while the sources are decreasing. The existing systems have not been able to cope up this developing situation. It is likely that with the fast increasing population will worsen this situation. All types of sciences, commerce and arts have not been able to provide the solutions to this situation so far. Nanotechnology is the new field which provides us some hope to meet the growing challenges. New wonder nanomaterials like carbon nano-tubes, fullerenes, bucky-balls, dendrimers, quantum dots, nano-crystals, titanium dioxide nano-particles, silver nano-particles, silver nano-wire and other such nano-sized particles have brought a change in the materials at a surface level but need now is changing the redundant systems into new workable nanotechnology systems which could provide worthwhile solutions to the ever growing problems. This concept paper aims at delineating the role of Nanotechnology in the new world.

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