Tiankai Li

Langmuir–Blodgett film and second harmonic generation of a new type of amphiphilic non-linear optical bis-chromophore complex dye

A bivalent zinc complex anion: bis(2-thione-1,3-dithiol-4,5-dimercapto)zinc, has been chosen to balance several non-linear optical (NLO) dye cations in the design and synthesis of a series of novel bis-chromophore complex dyes. The Langmuir film-forming properties of these new NLO complex dyes at the air/water interface, the stability and second-order non-linear optical properties of the monolayer and Langmuir–Blodgett multilayer films were investigated. Results show that both the film-forming properties and NLO coefficiencies were improved greatly when the zinc complex anion was incorporated into four types of NLO-active organic dyes.

LUMINESCENT EUROPIUM-DIBENZOYLMETHANE COMPLEXES AND THEIR LANGMUIR-BLODGETT FILMS

Abstract Two strong fluorescent amphiphilic europium-dibenzoylmethane complexes, hexadecyltrimethyl ammonium tetrakis (dibenzoylmethane) europium (A) and octadecyltriethyl ammonium tetrakis (dibenzoylmethane) europium (B), were synthesized and characterized by FT-IR, UV-vis, DTA-TG analysis and X-ray diffraction. Both of them could form stable Langmuir films at the air-water interface and the Langmuir film of A can be easily transferred onto hydrophilic substrates to build up Langmuir-Blodgett (LB) films. The LB film of A has a good layered structure, as confirmed by its low-angle X-ray diffraction. The fluorescence spectra and fluorescence lifetimes of the LB films were quite different from those of their corresponding solid powders and solutions.

Langmuir-Blodgett film study on N-hexadecyl pyridinium tetrakis (2-naphthyltrifluoroacetone) europium, HDP.Eu(NTA)4

Abstract The amphiphilic strong luminescence europium complex given in the title has been synthesized. Three isotherms at different temperatures were measured and the 15°C one has two different solid phases, indicating two kinds of molecular arrangements on the water surface. The monolayer was transferred on different hydrophilic pretreated plates using LB technique for different purposes. The LB films were characterized by IR, UV-vis and luminescence spectra.

Langmuir-Blodgett films of a series of new fluorescent ternary europium(III) complexes

Three europium complexes 1-methyl-4-octadecylpyridinium tetrakis(α-thenoyl trifluoroacetonato) europium(III), tris(α-thenoyl trifluoroacetonato) mono-(9-(4-hexadecylanilino)-4,5-diazafluorene) europium(III), and tris(α-thenoyltrifluoro acetonato) mono(2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline) europium(III) have been newly synthesized. They were capable of forming stable Langmuir films on pure water subphase(pH 5.6, 18 °C) with collapse pressures of 39.0, 50.0 and 20.5 mN/m, respectively. Langmuir-Blodgett films of these complexes have been prepared and studied by surface pressure-area isotherms, ultraviolet, fluorescent spectroscopy, fluorescent lifetime measurements and second-harmonic generation.

A new azo rare earth coordination compound for second-order non-linear optical Langmuir-Blodgett films

Abstract An amphiphilic lanthanide complex, ( E )-1-methyl-4-(2-(4-(dihexadecylamino)phenyl)azo)pyridinium tetrakis(1-phenyl-3-methyl-4-benzoyl-5-pyrazolonato)lanthanum(III), has been synthesized. It forms a stable Langmuir monolayer film on a pure water subphase (pH 5.6, 18°C) when spread from a chloroform solution. Langmuir-Blodgett (LB) films were prepared by transferring the monolayers onto hydrophilic substrates of quartz and calcium fluoride with a transfer ratio close to unity. From a second-harmonic generation measurement, the second-order molecular hyperpolarizability β of the complex was estimated to be about 1.4 × 10 −47 C m 3 V −2 , which is one of the largest values for azo-based, second-order non-linear optical materials reported so far. The infrared and variable-temperature ultraviolet spectra of the film are also reported.

Synthesis, characterization, Langmuir–Blodgett film deposition and non-linear optical properties of a series of new non-linear optical materials based on azo dyes containing europium complex anions

Several kinds of lanthanide complex containing a new azo dye chromophore, Me2NC6H4, NNC5H4NC18H37(EuA3A′), where A and A′ are β-diketones, have been designed and synthesized. Langmuir–Blodgett (LB) films of these compounds have been prepared. Most of them show both strong second-harmonic generation (SHG) and a high collapse pressure. The second-order molecular hyperpolarizabilities are evaluated to be ca.(1–2.5)× 10–27 esu.

Effect of gas environment on second harmonic generation of Langmuir-Blodgett films

The effect of the gas environment on the second harmonic generation of Langmuir-Blodgett films of non-linear material has been studied. It has been found that the gas environment in general had a strong effect on the structure and the non-linear optical property of the films. The phenomenon has a few implications for the applications of the non-linear optical material films.