Supramolecular Science最新文献

Cooperativity at the organic/inorganic interface is investigated at the Langmuir monolayer/nanoparticles interface with transmission electron microscopy and Brewster angle microscopy. Mineralization-induced collapse of the Langmuir monolayer is, for the first time, reported and factors that influence the cooperativity at the organic/inorganic interface are suggested. This study may provide an insight into the biomineralization and the fabrication of biomimetic materials.

The behavior of hot-electrons is very important for thin film electroluminescence (TFEL) devices. In SrS:Ce TFEL, the electrons in excited states of Ce³⁺ ions are easily to be ionized into conduction band under a high electric field, and are easily trapped by the ionized luminescent centers under a low electric field. In this paper, the dependence of ionization possibility on the field strength is studied and the emission wave forms were determined. The energy transfer process is discussed.

CdSe sensitized TiO₂ nanocrystalline solar cells were made with the participation of silicotungstic acid (STA) during the deposition of CdSe, the resulting Voc and Isc were 0.23 V cm^-2 and 10 mA cm^-2, respectively. The doping, time and microporous membrane effects were also discussed.

Self-assembled monolayers of 1-teradecanethiol on gold were characterized by means of FTIR-ATR measurements, XPS and contact angle measurements. Linear dichroism measurements using FTIR-ATR are used to estimate the orientation of the alkyl chains. An equation for calculating the orientation angles of the alkyls chains was deduced.

Molecular recognition directing self-assembly of two complementary molecular components, 5-(4-dodecyloxybenzylidene)-2,4,6-(1H,3H)-pyrimidinetrione (B) and 4-amino-2,6-didodecylamino-1,3,5-triazine (M), was found to form a mesoscopic supercoil structure with length of several tens of μm and diameter of ca. 300 nm. Fluorescence spectral studies show that it takes more than 1200 h for the self-assembling process to reach the equilibrium in chloroform. It was suggested that in this system with positive cooperation, at least two steps were involved in the self-assembling process. First, supramolecular tapes, cyclic hexamers, are formed based on the network of triple complementary hydrogen bonds between B and M. Second, π-aromatic stacking and van der Waals interactions drive further the assembling of tapes into more complex nanometric strand. The coiling of the strands results in the formation of the supercoil structure.

Surface pressure–area (π–A) isotherm characteristics of 5,10,15-(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl) porphyrin monolayers on both the water and TiO₂ hydrosol subphases, the UV–vis absorption and fluorescence spectra of the monolayers deposited onto CaF₂ substrates are investigated. π–A isotherms find that the porphyrin ring extends to lie more flat on a TiO₂ hydrosol surface than on a water surface. The UV–vis absorption spectra of the deposited monolayers prove that the porphyrin TiO₂ nanoparticle heterostructure assembly is formed, in which the J-aggregated effect of porphyrin is weakened, comparing with that in the monolayer deposited from water subphase. The fluorescence spectra show that the fluorescent emission quenching by the photoinduced electron transfer from the excited porphyrin molecule to TiO₂ nanoparticle, occurs under excitation in the Soret band region of porphyrin.

Organic electroluminescent (EL) devices with one layer of Alq(CH₃)₂ doped with poly(N-vinylcarbozle) (PVK) (Alq(CH₃)₂/PVK) as the EL-emitting layer sandwiched between indium tin-oxide (ITO) and aluminum electrodes have been fabricated by spin coating on to ITO. We found that two EL-peak intensities at the position of 520 nm from Alq(CH₃)₂ and at 470 nm from PVK change with different voltages applied to the organic EL devices. According to the analysis of the experimental results, it could be inferred that a charge transfer from Alq(CH₃)₂to PVK may take place in the Alq(CH₃)₂/PVK mixed film, leading to a much increased the EL intensity of the peak $\text{(λ=470}\text{nm}\text{)}$ from the PVK and a slight increase in the EL intensity of the peak $\text{(λ=520}\text{nm}\text{)}$ from Alq(CH₃)₂ with the voltage elevation at the higher voltages applied.

It is suggested that the appearance of Jordan blocks in the normal form of the recursion (transfer) matrix is responsible for high temperature superconductivity and related phenomena. Several published observations are discussed to support this idea. The draft of a quantum chemical theory is given for a more complete verification.

The system of real-time evolution and analysis of films’ parameters has been suggested and developed. Its principle is based on surface plasmon resonance. The results of Ag film left in air have been obtained by this system.

Using a needle-circle electrode configuration, we investigated the relationship between morphologies of polypyrrole (PPy) and polymerization conditions, such as the kinds of electrolyte, solvent and electrode, the concentrations of electrolyte and monomer, the applied voltages, etc. The various morphologies of PPy are classified into seven types. The influence of the substrate was also taken into account. Four types of morphologies of PPy under the mica are shown. We recently obtained organized PPy particles by the induction of the mica substrate. The neuron network-like interconnections of PPy fabricated by controlling the polymerization conditions are shown.