Trioctylphosphine selenide

Another study of the surface structure of CdSe NCs of 3.7 nm size used 31P MAS-NMR and 31P/77Se rotational-echo double-resonance (REDOR) to identify overlapping broad peaks from two surface species trioctylphosphine oxide (TOPO) at 29.3 ppm and trioctylphosphine selenide (TOPSe) at 22.2 ppm [343]. Both the isotropic chemical shift and CSA of the surface-bound TOPO were substantially different from those of the free ligand. Spin-echo experiments on 31P were stated to indicate an average P-P distance of 8-10 A at the surface, consistent with capping at alternate atomic sites (all Cd but not Se). 

Cn(hfac)2 (7b) °. The qnality of the copper fihns deposited on the SAM diffusion barrier was high regarding pnrity and nniformity, comparable to that of films deposited on Si(lOO) and traditional diffnsion barriers (TiN). Copper selenide binary phases can be grown from Cn(acac)2 (7a) and trioctylphosphine selenide. Depending on the techniques applied, tetragonal Cn2Se (aerosol-assisted CVD) or cnbic Cn2 xSe nanoparticles capped with hexadecylamine (liqnid deposition) are prodnced. ... 

In 1993, another milestone in the preparation of II-VI semiconductor nanocrystals was the study of Murray, Norris and Bawendi [12], whose synthesis was based on the pyrolysis of organometallic reagents such as dimethyl cadmium and trioctylphosphine selenide, after injection into a hot coordinating solvent. This approach provided a temporally discrete nucleation and permitted a controlled growth of the nanocrystals. The evolution of the absorption spectra of a series of CdSe crystallites, ranging in size from about 1.2 to 11.5 nm, is shown in Figure 3.11. 

Petchsang et al. reported the growth of ZnSe and ZnSe/CdSe eore/shell NWs by the solution-liquid-solid (SLS) growth method. ZnSe NWs of 15 to 28 nm diameter were synthesised by instant injection of a mixture of trioctylphosphine selenide (TOPSe), trioctylphosphine (TOP) and Bids to zinc stearate in trioetylphosphine oxide (TOPO) at 310 °C. Bismuth nano-partieles produeed from Bids catalysed the growth of ZnSe NWs as suggested by the SLS meehanism and were found attached at the tips of the nanowires (Fig. la). XRD analysis indieated the presence of both zinc... 

This technique is widely used for the fabrication of quantum dots. This can be illustrated by the preparation of near-monodisperse semiconductor CdSe nanocrystallites with diameters ranging from 1.2 to 11.5 nm by rapid injection of organometallic reagents (dimethylcadmium and tributylphosphine selenide) into a hot coordinating solvent (trioctylphosphine oxide) that acts as a capping agent [40]. This reaction can be carried out in macroscopic quantities in a single step. 

Trioctylphosphine oxide (TOPO) caps are used in quantum dots for LEDs moreover, the CdSe cores of these quantum dots can be obtained directly from cadmium selenide complexes as (12.401) [18,19]. Both TOPO and TOP can be used to produce various nanocrystals [20,21], Quantum dots of InP and GeP are being explored [22,23], Nickel nanoparticles, stabilised by TOPO, have been converted to Ni2P nanoparticles by the action of white phosphorus [21]. Highly luminescent nanocrystals of InP have been obtained. 

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