Study on Electronic Properties of Composite Clusters toward Nanoscale Functional Advanced Materials

Abstract

Clusters consisting of 101000 atoms size-dependently exhibit novel electronic and geometric properties. In particular, composite clusters composed of several elements and/or components provide a promising way for a bottom-up approach for designing functional advanced materials, because the functionality of the composite clusters can be optimized not only by the cluster size but also by their compositions. This account surveys recent investigations of composite clusters focusing on the efforts to create a new functional composite cluster by a fine doping or hybridization based on their size-specific electronic properties. Organometallic clusters and caged clusters are demonstrated as a representative example of designing the functionality of magnetism and electronic state structures. In order to create functional nanomaterials, furthermore, a fine controlling methodology of the soft-landing technique has been developed to fix the composite clusters onto a surface decorated with a self-assembled monolayer. The embedded isolation mechanism on the substrate is discussed form the viewpoint of self-assembly phenomena with the molecular ordering of ·· interaction, and also the electronic structures characterized by molecular ordering of ³³ interaction is intrinsically revealed by molecular clusters of ³-conjugate polyacenes as a model for self-assembled aggregates.

Synthesis and Characterization of Metal-Encapsulating Si16 Cage Superatoms

“…Systematic investigations on silicon-based inorganic BCSs is based on the development of the dual laser vaporization (DLV) nanocluster source (Figure ), , where the ratio of the two components can be changed through independent control of fluence and timing for the two lasers along with the helium (He) buffer gas. In 2005, we have found a periodic family of M@Si 16 BCSs based on mass spectrometry (Figure ) and anion PES (Figure ), where halogen-like (M III @Si 16 – ), rare gas-like (M IV @Si 16 (0) ), and alkali-like (M V @Si 16 + ) SAs have been demonstrated by the doping of group 3, 4, and 5 atoms, respectively.…”

“…A schematic DLV setup for the modified “face-to-face” nanocluster source combined with a flow-tube reactor. , Reproduced with permission from ref . Copyright 2013 Chemical Society of Japan.…”

Vibrational Spectra of Thiolate-Protected Gold Nanocluster with Infrared Reflection Absorption Spectroscopy: Size- and Temperature-Dependent Ordering Behavior of Organic Monolayer

“…The prepared sample was loaded to a temperature variable sample holder in a vacuum chamber with ∼10 –9 Torr. Details of the IRAS measurements are described elsewhere. , Briefly, a collimated infrared (IR) beam from an FT-IR spectrometer (IFS 66v/s, Bruker) was irradiated to substrate and the reflection component was detected using a liquid-nitrogen-cooled mercury cadmium telluride (MCT) detector. The temperature of the substrates was controlled from 100 to 340 K by combining a liquid nitrogen reservoir and a ceramic heater.…”

Characterization of floating-gate memory device with thiolate-protected gold and gold-palladium nanoclusters

“…The SiO 2 surface was then dried under N 2 gas, followed by ultraviolet (UV)/ozone cleaning for 20 min. Second, the 18 was used in this study.…”

“…[7][8][9][10][11] Among chemically synthesized nanomaterials such as nanoparticles (NPs), nanowires, and nanorods, metal nanoclusters are remarkable nanomaterials because of their potential applications as building blocks of functional nanomaterials: [12][13][14][15][16][17][18][19] Not only cluster size but also metal composition by alloying enable us to design the physical and chemical properties of nanoclusters. 12,[16][17][18]20 Since those properties strongly depend on geometric and electronic structures of nanoclusters, tailoring characteristics of electronic devices could be achieved by utilizing size-and composition-selected nanoclusters. In addition, the passivation of metal nanoclusters by organic ligands prevents deterioration along with extension to the tuning of properties by chemical designed ligands; In particular, thiolate passivated gold nanoclusters (Au:SR) are known to exhibit particularly high stability against degradation.…”