16986-83-7Relevant articles and documents
Selective electrophoretic deposition of CdSe nanoplatelets
Lhuillier, Emmanuel,Hease, Patrick,Ithurria, Sandrine,Dubertret, Benoit
, p. 4514 - 4520 (2014)
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.
Ultrasonic Absorption Study of the Complex Formation of Cadmium(II) Carboxylates in Aqueous Solution
Tamura, Kiyoshi
, p. 3425 - 3429 (1991)
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.
Shape control of zincblende CdSe nanoplatelets
Bertrand, Guillaume H.V.,Polovitsyn, Anatolii,Christodoulou, Sotirios,Khan, Ali Hossain,Moreels, Iwan
supporting information, p. 11975 - 11978 (2016/10/09)
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.
