Hong-Xiang Huang

Monolayers of europium complex mixed with stearic acid and fluorescence properties in Langmuir–Blodgett films

Abstract Monolayers of bis(tri-n-octylphosphine oxide) europium (III) tri(thienyltrifluoro-acetonate) and its mixtures with stearic acid (SA) have been investigated on pure water and a europium complex subphase surfaces. By the observation of Brewster angle microscopy, it was found that homogeneous monolayers were formed by the complex alone and the mixtures with low concentrations of SA, and the complex was squeezed out of the matrix of SA when the molar fractions of SA up to 1:8. Mixed monolayers were successfully deposited onto solid substrate by Langmuir–Blodgett method. The emissions of the complex in the monolayer assemblies mixed with SA indicated that the relative intensity of 5 D 0 → 7 F 2 vs. 5 D 0 → 7 F 1 become higher with the molar fractions of SA, due to the slightly distortion for the complex in the closely packed structure.

Europium complex nanoparticles: preparation, characterization and optical properties

Spherical, rod-like europium complex nanocrystals or their irregular ultrafine particles have been synthesized in a colloidal solution by using cationic surfactant as a soft template. These Eu complex nanoparticles showed much stronger fluorescence emission than a precipitate prepared from the same solutions but without surfactant.

Self-assembled monolayers of pyridylthio-functionalized carbon nanotubes used as a support to immobilize cytochrome c

Self-assembled monolayers (SAMs) of pyridylthio-functionalized multiwalled carbon nanotubes (pythio-MWNTs) have been constructed on the gold substrate surface, which were used as a support to immobilize cytochrome c (Cyt c). The assembly processes of the SAMs and adsorption of Cyt c were monitored by using quartz crystal microbalance (QCM). Based on the frequency change of the QCM resonator, the surface coverage for the SAMs of pythio-MWNTs was estimated to be about 5.2 μg/cm2, and that of the Cyt c adsorbed was about 0.29 μg/cm2. For the gold electrode modified by the SAMs of pythio-MWNTs-Cyt c, a quasi-reversible redox wave was recorded with the cathodic and anodic potentials at about −0.55 and −0.28 V vs Ag/AgCl, respectively. Compositions and morphologies of the SAMs before and after immobilization of Cyt c were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy.