the synthesized CdSe quantum dots showed a blue …
Emerging Focus on Advanced Materials: Synthesis and Properties of CdSe/Cd X Zn 1-X S Quantum Dots
Synthesis of CdSe/ZnS and CdTe/ZnS quantum dots
In this work, a simple, effective and reproducible synthetic route (single pot approach) for the preparation of high quality core–shell CdSe–ZnSe quantum dots (QDs) without the use of any pyrophoric organometallic precursors is presented. Effective surface passivation of stoichiometric, monodispersed, small sized (?5 nm) CdSe nanocrystallites is achieved by overcoating them with a ZnSe shell using zinc acetate as a zinc source by single pot approach. The resulting core–shell nanocrystallites exhibit high quantum yield values (?11·33%), narrow linewidth of the photoluminescence (PL) band, stable surface bonds configuration and superior structural properties at lower Zn content (?10 at-%). With increasing Zn content (?20 at-%), a composition tunable emission across the visible spectrum has been demonstrated by a systematic blue shift in emission wavelength due to the formation of ternary ZnxCd1–xSe QDs with acceptable luminescence properties. Here, contribution to emission process from surface states of nanocrystallites increases with zinc content. The core–shell and ternary QDs formed by different routes are modelled, based on the observations of several complimentary techniques (XPS depth profiling, PL, UV-Vis absorbance and TEM/TED). The improved properties of core–shell CdSe–ZnSe QD with similar zinc content using single pot synthesis approach as compared to the corresponding samples obtained by double pot synthesis are due to better passivation effect rendered by thin ZnSe shell in the former as compared to the latter. Their strong luminescence, narrow emission bands and wide colour tunability make such QD structures attractive for various scientific and commercial applications.
We report a facile and robust synthesis of CdZn1–S graded shells on CdSe nanoparticles that are prepared by interface alloying between CdS and ZnS shells at elevated temperatures. Alloying provides systematic control over the electronic structure and enables switching between Type-I and -Type-II configurations. Good control of particle shape, shell thickness, and composition is achieved by slowly adding zinc oleate and octane thiol via syringe pump to readily prepared CdSe/CdS particles. The resultant quantum dots exhibit PL quantum yields of up to 97% and superior robustness toward environmental influences and quenching agents. Alloying promotes a blue-shift of both the absorption and PL spectra compared to pure CdSe/CdS particles and an increased Stokes shift, opening a new synthetic pathway to stable, green-emitting core/shell/shell quantum dots. High PL quantum yields are correlated to a narrow distribution of single-particle lifetimes and suppressed fluorescence intermittency. We introduce a new method to characterize the PL intermittency of single quantum dots based on the autocorrelation function of their PL time trajectories.
Facile and Green Synthesis of CdSe Quantum Dots in …
73. Gerion D, Pinaud F, Williams SC, Parak WJ, Zanchet D, Weiss S. . Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots. 2001;105:8861-71
54. Dabbousi BO, Rodriguez-Viejo J, Mikulec FV, Heine JR, Mattoussi H, Ober R. . (CdSe)ZnS Core-Shell Quantum Dots: Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites. 1997;101:9463-75
‘Giant’ CdSe/CdS Core/Shell Nanocrystal Quantum Dots …
46. Lin AWH, Ang CY, Patra PK, Han Y, Gu H, LeBreton JM, Juraszek J, Chiron H, Papaefthymiou GC, Selvan ST, Ying JY. Seed-mediated synthesis, properties and application of γ-Fe2O3-CdSe magnetic quantum dots. 2011;184:2150-8
Preparation of Quantum Dot/Drug Nanoparticle …
Synthesis, Characterization, and Optical Properties of Quantum Dots
Facile and Green Synthesis of CdSe Quantum Dots in Protein Matrix: Tuning of Morphology and Optical Properties
Journal of Nanoscience and Nanotechnology
‘Giant’ CdSe/CdS Core/Shell Nanocrystal Quantum Dots As Efficient Electroluminescent Materials: Strong Influence of …
Quantum Materials Corporation QTMM Board - InvestorsHub
Quantum dot - Wikipedia
"I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."
"Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."
"Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."
"Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."
"Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."
"Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."