Absorption core-shell

Michaelis and Henglein [131] prepared Pd-core/Ag-shell bimetallic nanoparticles by the successive reduction of Ag ions on the surface of Pd nanoparticles (mean radius 4.6 nm) with formaldehyde. The core/shell nanoparticles, however, became larger and deviated from spherical with an increase in the shell thickness. The Pd/Ag bimetallic nanoparticles had a surface plasmon absorption band close to 380 nm when more than 10-atomic layer of Ag are deposited. When the shell thickness is less than 10-atomic layer, the absorption band is located at shorter wavelengths and the band disappears below about three-atomic layer. 

Figure 14.1 QD-MBP-dye nanoassembly, (a) Schematic representation of the QD-MBP-dye nanoassembly used (not drawn to scale). The distance r represents the average distance between the QD center and the Cy3-labeled residue on MBP. (b) Normalized absorption spectra of Cy3 dye and photoemission spectra of three CdSe-ZnS core-shell QD solutions demonstrating the ability of tuning the spectral overlap of the QD with a given dye acceptor. Adapted from reference 28 and reprinted by permission of the American Chemical Society.

Py showing CdS band gap (left panels) and Co2+ ligand-field (right panels) absorption. Note the different x and y axes for the two energy regions. The solid line was collected 2 h and the dashed line 23 h after suspension in Py. (b) Absorption spectra (300 K) of 3.7-nm diameter 0.9% Co2+ CdS QDs prepared by the isocrystalline core shell method 2h (solid) and 28 h (dashed) after synthesis. [Adapted from (68).]... 

Fig. 14 TEM images of core-shell nanopariicles of (a) ReO, Au formed with a 5 nm ReOj particle. Inset shows Re03 Au formed over an 8 nm Re03 particle, (b) Re03 Ti02 core-shell nanoparticle formed over a 32 nin Re03 particle with the inset showing a core-shell nanoparticle formed over a 12 nm ReO, nanoparticle, UV-visible absorption spectra of (e) Re03 Au core-shell nanoparticles (1 2 and 1 4). and (d) Re03 Ti02 core-shell nanopariicles (1 2 and 1 4) with a 12 nm ReO, particle (From Ref. [140]),...

Figure 9 Absorption spectra for bare (dashed lines) and 1-2 monolayer ZnS-overcoated (solid lines) CdSe NQDs. (Core)shell spectra are broader and slightly red-shifted compared to the core counterparts. Core diameters are (a) 2.3, (b) 4.2, (c) 4.8, and (d)5.5nm. (Reprinted with permission from Ref. 31. 1997 American Chemical Society)...

Figure 18 Absorption (solid line) and PL (dashed line) spectra for medium-length (3.3 x 21 nm) CdSe nanorods, (a) Core nanorods without ZnS shell, (b) (Core)shell nanorods with thin CdS-ZnS shells ( 2 monolayers of shell material, where the CdS buffer shell comprises 35% of the total shell), (c) (Core)shell nanorods with medium CdS-ZnS shells ( 4.5 monolayers of shell material, where the CdS buffer shell comprises 22% of the total shell). PL spectra were recorded following photoannealing of the samples ...

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