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.

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.

Two indole-based organic dyes were conveniently prepared and well characterized. The triphenylamine or carbazole moieties were bonded to the indole group acting as a potential electron donor, which can tune the HOMO and LUMO levels of the resultant dye, and another triphenylamine or carbazole group was linked to the pyrrole ring on the nitrogen atom, which was expected to suppress the aggregation of the dye in the solid state to some degree. These two dyes were utilized as dye sensitizers in dye-sensitized solar cells and demonstrated efficient photon-to-electron conversion properties.

A series of new carbazole-based luminophores (1-12) were synthesized and well characterized, which demonstrated aggregation-induced emission enhancement (AIEE) properties. The obtained experimental results demonstrated that the attachment of aromatic rotors to luminophore moieties would lead to the decreased quantum yields (measured in diluted solutions); the more rotors attached, the smaller the quantum yields tested. This further confirmed that the AIEE phenomena were caused by the restriction of the intramolecular vibrational and rotational motions in an indirect manner.

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.