Fluorescent organic nanoparticles of benzofuran-naphthyridine linked molecules: formation and fluorescence enhancement in aqueous media.

[structure: see text] Ethynyl-linked benzofuran-naphthyridine compounds show high-yield fluorescence with solvatochromic properties. One of the compounds, ABAN, has successfully formed fluorescent organic nanoparticles (FONs), for which the photophysical properties such as the spectral features and intensity are remarkably different from those at the molecular level (solution) and in bulk material. The results are tentatively rationalized by the FONs inducing coplanarization of the benzofuran-naphthyridine molecule to extend its effective conjugation length and hence increase the oscillator strength.

Photosensitive gold-nanoparticle-embedded dielectric nanowires.

Noble-metal nanoparticles embedded in dielectric matrices are considered to have practical applications in ultrafast all-optical switching devices owing to their enhanced third-order nonlinear susceptibility, especially near the surface-plasmon-resonance (SPR) frequency. Here we present the use of a microreactor approach to the fabrication of a self-organized photosensitive gold nanoparticle chain encapsulated in a dielectric nanowire. Such a hybrid nanowire shows pronounced SPR absorption. More remarkably, a strong wavelength-dependent and reversible photoresponse has been demonstrated in a two-terminal device using an ensemble of gold nanopeapodded silica nanowires under light illumination, whereas no photoresponse was observed for the plain silica nanowires. These results show the potential of using gold nanopeapodded silica nanowires as wavelength-controlled optical nanoswitches. The microreactor approach can be applied to the preparation of a range of hybrid metal-dielectric one-dimensional nanostructures that can be used as functional building blocks for nanoscale waveguiding devices, sensors and optoelectronics.