Application of Plasmonic and Semiconductor Nanoparticles to Optical Materials

Construction of enhanced electric field using plasmonic (Au, Ag, Cu) nanoparticles would enable us to develop the novel chemical reactions with weak-intensity and/or low-energy photons. The regularly ordered nanoparticle superlattices will be the promising candidates for this purpose. Also we would like to apply the semiconductor nanoparticles to high-luminescent materials and photoelectric materials






Control of SPR Intensities of Au Nanoparticles



UV-vis spectra of [AuCl4]-ions, 1.5±0.2 nm C12S-Au, 3.4±0.3 nm C12S-Au,
5.4±0.7 nm C12S-Au, and 6.8±0.5 nm C12S-Au nanoparticles.

[Ref.] Adv. Mater. 2001, 13, 1699.; J. Phys. Chem. B 2003, 107, 2719.


Direct Silica-Coating of Hydrophobic Au Nanoparticles



Direct silica-coating of C12S-Au nanoparticles and the formation of hollow silica particles by etching the Au nanoparticles.

[Ref.] J. Nanosci. Nanotech. (Communications), accepted.


Room Temperature Size Evolution of Thiol-Protected Gold Nanoparticles
An essential approach to the photoelectric field enhancement of Au nanoparticles is to use the easily available low-molecular weight ligand, although the post thermal annealing process is not applicable to such thermally-unstable ligand molecules. We have demonstrated the novel method to control the size of thermally-unstable ligand-protected Au nanoparticles by using proton acids and halogen anions at room temperature. Mean diameters of monodisperse Au nanoparticles could be controlled from 2 to 7 nm by changing the amount and/or the kind of proton acids and halogen anions.




Room Temperature Size Evolution of Thiol-Protected Gold Nanoparticles Assisted by Proton Acids and Halogen Anions

[Ref.] J. Am. Chem. Soc., accepted.


Control of Particle Size and PLt Wavelength of CdSe Nanoparticles



Control of PL wavelength of CdSe nanoparticles. (λex: 365 nm)

[Ref.] Chem. Lett. 2005, 34, 1004.