ABSTRACT
Boosting nonlinear frequency-conversion efficiencies in hybrid metal-dielectric nanostructures generally requires the enhancement of optical fields that interact constructively with nonlinear dielectrics. Inevitably for localized surface plasmons, spectra subject to this enhancement tend to span narrowly. As a result, because of the spectral mismatch of resonant modes at frequencies participating in nonlinear optical processes, strong nonlinear signal generations endure the disadvantage of rapid degradations. Here, we experimentally design a multiband enhanced second-harmonic generation platform of three-dimensional metal-dielectric-metal nanocavities that consist of thin ZnO films integrated with silver mushroom arrays. Varying geometric parameters, we demonstrate that the introduction of ZnO materials in intracavity regions enables us to modulate fundamental-frequency-related resonant modes, resulting in strong coupling induced plasmon hybridization between localized and propagating surface plasmons. Meanwhile, ZnO materials can also serve as an efficient nonlinear dielectric, which provides a potential to obtain a well-defined coherent interplay between hybridized resonant modes and nonlinear susceptibilities of dielectric materials at multi-frequency. Finally, not only is the conversion efficiency of ZnO materials increased by almost two orders of magnitude with respect to hybrid un-pattered systems at several wavelengths over a 100-nm spectral range but also a hybrid plasmon-light coupling scheme in three-dimensional nanostructures can be developed.
ABSTRACT
Recently, the photoelectric effect in metals in electrolyte environments has aroused the interest of researchers. However, direct evidence for surface plasmons-enhanced electrochemical reactions involving classic outer-sphere reactions of reversible redox couples is seldom reported. We used a surface plasmons-active gold-mushroom-array as a working electrode and observed enhanced faradaic current from ferrocenemethanol following illumination with a xenon lamp. The photoelectric current behaved differently in the presence and absence of oxygen in the solution. The preliminary results are discussed with consideration of the possible mechanisms of electron transfer, although they are very complex, due to the lack of direct evidence. Some consideration was also taken of the research on photoelectrochemical reactions on metallic electrodes.
ABSTRACT
In the title compound, {[Fe(C(10)H(8)N(2))(2)(H(2)O)(2)](C(12)H(7)N(2)O(4)S(2))(2)}(n), synthesized by hydro-thermal reaction, the 4,4'-bipyridyl ligands (one with symmetry 2, one with symmetry [Formula: see text]) connect Fe(2+) cations, forming a cationic layer parallel to (001). The coordination of the Fe(2+) cation (site symmetry 2) is octahedral, with four N atoms from four 4,4'-bipyridyl ligands and O atoms from two trans water molecules. Adjacent layers are linked with each other by inter-molecular O-Hâ¯O hydrogen bonds, forming a three-dimensional supra-molecular structure. Parts of the nicotinic acid derivative are equally disordered over two sets of sites.
