Bound-Ion Pair X-Type Ligation of Cadmium and Zinc Dithiocarbamates on Cadmium Selenide Quantum Belts.

Wurtzite CdSe quantum belts with L-type -octylamine, L-type ammonia, or Z-type Cd(oleate) ligands are exchanged for several metal-dithiocarbamate ligands [M(SCNRR)]: Cd(SCNPhMe), Cd(SCNEt), Zn(SCNPhMe), and Zn(SCNEt). Successful ligand exchange with all M(SCNRR) compounds occurs from {CdSe[Cd(oleate)]} quantum belts (QBs), which induce similar spectral shifts in the absorption spectra of the ligand-exchanged QBs. Spectroscopic data, experimentally determined lattice strains, and ligand exchanges with [Na][EtNCS] and [NH][MePhNCS] establish that the [M(SCNRR)] ligands bind as bound-ion-paired X-type ligands with (SCNRR) groups ligated directly to the QB surfaces and [M(SCNRR)] groups serving as the charge-balancing ion-paired countercations.

Excitation Energy Dependence of Photoluminescence Quantum Yields in Semiconductor Nanomaterials with Varying Dimensionalities.

The excitation energy dependence (EED) of the photoluminescence quantum yield (Φ) of semiconductor nanoparticles with varying dimensionalities is reported. Specifically, the EEDs of CdSe quantum dots, CdSe quantum platelets, CdSe quantum belts, and CdTe quantum wires were determined via measurements of individual Φ values and photoluminescence efficiency (PL()) spectra. There is a general trend of overall decreasing efficiency for radiative recombination with increasing excitation energy.

Cadmium Bis(phenyldithiocarbamate) as a Nanocrystal Shell-Growth Precursor.

Cadmium bis(phenyldithiocarbamate) [Cd(PTC)] is prepared and structurally characterized. The compound crystallizes in the monoclinic space group P2/n. A one-dimensional polymeric structure is adopted in the solid state, having bridging PTC ligands and 6-coordinate pseudo-octahedral Cd atoms.