- Selective electrophoretic deposition of CdSe nanoplatelets
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In the fields of nanoparticle synthesis and application, the control of the particle size, shape and composition is crucial. The tuning of these different parameters can be performed during the synthesis, but often, additional selection steps to improve the purity of a given nanoparticles' population are necessary. These additional postsynthesis selection steps, that can include size selective precipitation, ultracentrifugation or liquid chromatography, are usually long and not well suited for a large quantity of materials. Here, we demonstrate that electrophoresis performed directly in organic solvent can be used to select and/or separate semiconductor nanoparticles according to their size and shape. In particular, we show that 2D nanoplatelets (NPL) can be very efficiently separated from spherical nanoparticles as the side product obtained during the NPL synthesis. The selectivity of the electrophoretic deposition we observe is mostly related to the nanoparticle surface charge. We show that centimeter scale, uniform film of nanoplatelets can be obtained even on nonconducting substrates. Compared to other methods this technique is fast, easy to implement and scalable, and should find various uses both in the fields of the nanoparticle synthesis and their applications.
- Lhuillier, Emmanuel,Hease, Patrick,Ithurria, Sandrine,Dubertret, Benoit
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- Thermal characterization of new complexes of Zn(II) and Cd(II) with some bipyridine isomers and propionates
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New mixed ligand complexes of the following stoichiometric formulae: M(2-bpy)2(RCOO)2?nH2O, M(4-bpy)(RCOO) 2?H2O and M(2,4'-bpy)2(RCOO) 2?H2O (where M(II)=Zn, Cd; 2-bpy=2,2'-bipyridine, 4-bpy=4,4'-bipyridine, 2,4'-bpy=2,4'-bipyridine; R=C2H5; n=2 or 4) were prepared in pure solid-state. These complexes were characterized by chemical and elemental analysis, IR and conductivity studies. Thermal behaviour of compounds was studied by means of DTA, DTG, TG techniques under static conditions in air. The final products of pyrolysis of Cd(II) and Zn(II) compounds were metal oxides MO. A coupled TG/MS system was used to analyse of principal volatile products of thermal decomposition or fragmentation of Zn(4-bpy)(RCOO)2?H2O under dynamic air and argon atmosphere. The principal species correspond to: C+, CH+, CH3 +, C2H2+, HCN+, C 2H5+ or CHO+, CH2O + or NO+, CO2+, 13C 16O2+ and 12C16O 18O+ and others; additionally CO+ in argon atmosphere.
- Czakis-Sulikowska,Radwannska-Doczekalska,Markiewicz,Pietrzak
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- Ultrasonic Absorption Study of the Complex Formation of Cadmium(II) Carboxylates in Aqueous Solution
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Ultrasonic absorption of aqueous cadmium(II) acetate, propionate, and n-butyrates has been measured with a pulse technique over a frequency range 3-260 MHz.The single relaxations observed in the metal-rich concentration regions are attributed to the complex formation of cadmium(II) carboxylates via the Eigen-Tamm mechanism of stepwise association.The reaction parameters are determined from the concentration dependences oh the relaxation frequency and amplitude.The association constant for outer-sphere complexing and the rate constant for ligand substitution lie in the range 0.91-1.14 and (4.1-5.4) * 108 s-1, respectively, both being almost independent of the nature of the carboxylate ions, in contrast to the zinc(II) carboxylates previously reported.The volume changes of the outer-sphere complexing and those of the ligand substitution are determined to be 1.7-2.4 and 4.6-6.7 cm3 mol-1, respectively; these values are very different from those of cadmium(II) thiocyanate reported earlier.
- Tamura, Kiyoshi
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- Electrochemical synthesis of cadmium(II) carboxylates compounds at sacrificial cadmium anode
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Cadmium carboxylates and their coordination complexes are synthesized by using an electrochemical technique in the presence of different carboxylic acids (RCOOH) using cadmium and a platinum as the anode and cathode respectively and tetrabutyl ammonium chloride as a supporting electrolyte. The electrochemical oxidation of anodic cadmium in acetonitrile solution with different carboxylic acids or with 1,10-phenanthroline (phen) and 2,2'-bipyridyl (bipy) yield the complexes Cd(OOCR)2 and Cd(OOCR)2L (L = phen or bipy), respectively. The results from spectroscopic studies FTIR, elemental analysis and physical measurements confirm the existence of bonding between the carboxylate groups of different carboxylic acids with cadmium. Current efficiencies of all these synthesized compounds are also discussed.
- Bala, Kanchan,Singh, Baljit
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- Shape control of zincblende CdSe nanoplatelets
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The lateral dimensions of CdSe nanoplatelets have a strong and unique influence on their opto-electronic properties, with sizes that can be tuned from the weak to the strong exciton confinement regime. There are state-of-the-art reports on several nanoplatelet syntheses; however, at present only the thickness is well-controlled. We demonstrate here that we can achieve a control over the aspect ratio and overall nanoplate area by carefully adjusting the reagents that induce the in-plane growth. A variation of the fraction of hydrated Cd(OAc)2 in a Cd(OAc)2/Cd(OAc)2·2H2O mixture tailors the nanoplatelet aspect ratio. This occurs independently of the reaction time, which can be used to fine-tune the overall length and width. An interpretation is given by the in situ formation of a small amount of hydroxide anions that alter the surface energy of specific planes.
- Bertrand, Guillaume H.V.,Polovitsyn, Anatolii,Christodoulou, Sotirios,Khan, Ali Hossain,Moreels, Iwan
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supporting information
p. 11975 - 11978
(2016/10/09)
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- Decomposition of organic salts of some d and f metals: Non-isothermal kinetics and FT-IR studies
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The thermal decomposition in non-isothermal conditions of formates, acetates, propionates and butyrates of Mn, Co, Zn, Cd, Eu, Sm and Ni was studied. The observed compensation effect allows us to calculate the isokinetic temperature. A selective activation mechanism was suggested. This leads to a good agreement between kinetic and spectroscopic data.
- Vlase,Vlase,Chiriac,Doca
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p. 839 - 845
(2008/10/08)
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- Aspects of the Inorganic Chemistry of Rubber Vulcanisation. Part 3. Anionic Cadmium Complexes derived from Dialkyldithiocarbamates, 2-Mercaptobenzothiazole and its Derivatives, and Dialkyl Dithiophosphates, and the the Crystal and Molecular Structures of n4>...
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The reactions of with certain Lewis bases are described, and the complexes n4>, (R = Me or Bun; R' = Me, Et, Bun, or NHNMe2), , (R = Me or Bun), , (R = H or EtO, py = pyridine), n(6-EtOC7H3NS2)3-n> n = 0-3,NBun>, and I)2)3> have been prepared.The structures of the title compounds have been determined crystallographically.All three anions have geometries intermediate between trigonalprismatic and octahedral; in the second, the C7H4NS2-ligand is bound to the metal via the N and the exocyclic S (thiolate) atoms.Thes estructures are compared with those of the corresponding zinc complexes and (1-).
- McCleverty, Jon A.,Gill, Stephen,Kowalski, Rick S. Z.,Bailey, Neil A.,Adams, Harry,et al.
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p. 493 - 504
(2007/10/02)
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