For the first time, a conjugated fluorescent polymer was utilized to probe R-amino acids, sensitively and selectively, through a new approach. First the strong fluorescence of the prepared polyfluorene (P1) was quenched by trace copper ions, and then the quenched fluorescence was recovered upon the addition of R-amino acids, making P1 a new and sensitive biosensor toward R-amino acids. The experimental results demonstrated that the R-amino acid selective nature of P1 over other analytes was relatively good. Thus, the work reported here might open up a new avenue for developing new biosensors.

On the basis of the protection reaction between ethanethiol and aldehyde, we designed and synthesized two new ratiometric fluorescent chemosensors, 3 and 4, by using intramolecular charge transfer (ICT) as a signaling mechanism. Upon the addition of Hg2+ ion, both probes displayed apparent luminescence color changes, which could be observed by naked eyes under a UV lamp. Unexpectedly, both chemosensors also gave response to the addition of trace silver ions, making this kind of chemosensors as the first example of ratiometric fluorescent probe that showed dual channel fluorescence for both Hg2+ and Ag+. The test strips experiments suggested that 3 and 4 could serve as practical fluorescent probes for rapid detection of Hg2+ ion.

For the first time, a series of dendronlike main-chain polyurethanes have been successfully designed and synthesized, in which different isolation groups with different sizes were introduced to modify the subtle structure of the used "H"-type chromophores, according the concept of "suitable isolation groups". Thanks to the advantages of "H"-type chromophores and the introduced suitable isolation group, all of the polymers demonstrated large NLO effects, good processability, improved optical transparency, and thermal stability. The obtained experimental results indicated that the utilization of "H"-type chromophores might be a promising choice to efficiently translate the large-values of the organic chromophores into high macroscopic NLO activities of polymers.

By applying an indirect strategy, a new rhodamine-based dye (I) was successfully developed as a colorimetric chemosensor for the sensitive detection of cyanide. In the presence of copper ions, the colorless solution of compound I changed to magenta; however, upon the addition of trace cyanide, the magenta color faded to colorless immediately, with a detection limit as low as 0.013 ppm (ΔA) 0.054), much lower than the Maximum Contaminant Level for cyanide in drinking water (0.20 ppm) set by the US Environmental Protection Agency. Other anions, including Cl-, I-, IO3-, SO4 2-, NO2-, Br-, H2PO4-, F-, SCN-, HSO4-, and ClO4-, had nearly no influence on the probing behavior of dye I toward cyanide.

Two new dendronized nonlinear optical (NLO) polyfluorenes were synthesized with high azochromophore loading density by the introduction of high generation chromophore dendrons on the side chains. Thanks to the advantages of Sharpless' click chemistry reaction, the dendrons were conveniently bonded to the backbone of polyfluorene with the conversion of 100%, although they were really very bulky. The new-formed triazole rings in the dendrons acted as suitable isolation groups to minimize the strong dipole-dipole interactions among the polar chromophore moieties to improveNLO effects, according to the results obtained from UV-vis spectra and order parameters. All the polymers were well characterized and exhibited good solubility, high thermal ability, wide optical window, and largeNLOeffects (up to 106.0 pm/V). In addition, the testedNLOresults of these dendronzied polymers demonstrated a deviation from the dipolar frustration that typically limits the NLO effect in conventional chromophore/polymer composite materials, indicating that the frequently observed asymptotic dependence of electro-optic activity on chromophore density may be overcome through rational design.

By modifying the synthetic procedure, the previous reported impossible approach was successfully utilized to construct new azo-chromophore-containing hyperbranched polymers (HP1 and HP2) from AB2 monomers through click chemistry reactions with the aid of copper(I) catalysis. The two polymers were soluble in organic solvents and well characterized. Thanks to the advantages of the hyperbranched polymeric structure, the two polymers demonstrated good NLO properties, making them promising candidates for the practical applications.

To develop sensitive and selective CN-chemosensors, a new imidazole-functionalized polyfluorene (P1) was designed and obtained conveniently, the fluorescence of which could be completely quenched by Cu2+ ions at the concentration as low as 0.20 ppm in diluted solutions. By utilizing the much higher stability constant of the complex of CN-and Cu2+, the quenched fluorescence of the solution of P1 by Cu2+ ions could recover upon the addition of trace CN-anions, with the detection limit down to 0.31 ppm, making P1 a novel, sensitive and selective cyanide probe.

A novel series of indole-based conjugated oligomers were synthesized by Wittig-Horner-Emmons olefination from the aryl-bridged bisindole aldehydes and the corresponding bisphosphonates. The introduction of indole into the light-emitting materials made these oligmers exhibit favorable properties. They were thermally stable, and the UV-vis spectra of the oligomers could be modulated by the arylenevinylene units; their PL and EL spectra also showed similar properties that can be further modulated. The highest luminance achieved in a device with the configuration ITO/PEDOT:PSS/oligomer/Ba/Al was 2536 cd/m2 at 7.5 V for oligomer P6, and the highest external EL quantum efficiency of 0.39% and luminous efficiency of 0.97 cd/A were attained by oligomer P1.