Jianhua Su

A dual-ion-switched molecular brake based on ferrocene

A new dual-ion-switched molecular brake was synthesized and operated by chemical reagents (H+/OH- and Zn2+/EDTA), and its rotation could be read out by chromogenic, fluorogenic and electrochemical signals.

Rigid triarylamine-based efficient DSSC sensitizers with high molar extinction coefficients

Five metal-free organic dyes (DIA1–DIA5) based on rigid triarylamine donors have been synthesized and their photophysical/electrochemical properties, theoretical calculations and dye-sensitized solar cell (DSSC) performances have been investigated. All the five dyes showed a high molar extinction coefficient (5.0 × 104–8.1 × 104 M−1 cm−1). Electrochemical measurement data indicates that the HOMO and LUMO energy levels can be conveniently tuned by alternating the π-spacer moiety. Among the five dyes, DIA3 showed the best photovoltaic performance, which was greatly increased to 8.09% by an optimized condition under standard global AM 1.5 solar light condition. The results show that the dyes based on this rigid donor are promising candidates for the improvement of the performance of DSSCs.

Efficient and stable DSSC sensitizers based on substituted dihydroindolo[2,3-b]carbazole donors with high molar extinction coefficients

Four novel metal-free organic sensitizers based on 5,7-dihexyl-6,12-diphenyl-5,7-dihydroindolo[2,3-b]carbazole (DDC) donors have been synthesized. Their optical/electrochemical properties, dye-sensitized solar cell (DSSCs) performances and photo-stability upon successive irradiation for 30 min have been investigated. The optical data indicates that all these dyes showed a high molar extinction coefficient (5.6–6.3 × 104 M−1 cm−1). Under standard global AM 1.5 solar light condition, the DDC4 sensitized cell gave a short circuit photocurrent density (Jsc) of 14.81 mA cm−2, an open circuit voltage (Voc) of 0.688 V, and a fill factor (FF) of 0.69, corresponding to an overall efficiency (η) of 7.03%. The benzothiadiazole units and thieno[3,2-b]thiophene (TT) in the π spacer were found to increase the photo-stability of the corresponding dyes and these dyes based on this donor are promising candidates for the further application in DSSCs.

Large cyano- and triazine-substituted D–π–A–π–D structures as efficient AIEE solid emitters with large two-photon absorption cross sections

A series of new large π-conjugated molecules including diphenylamine and carbazole have been synthesized and characterized (3a–c). All compounds display aggregation-induced emission enhancement (AIEE) characteristics: exhibiting weak fluorescence in pure THF, while a significant AIEE effect is observed in mixtures with a water fraction (fw) of 90% with a sharp increase in fluorescence intensity. Combining intramolecular charge transfer (ICT) characteristics and AIEE features, 3a–c are intense solid emitters (589 nm, 546 nm and 556 nm, respectively) with high quantum efficiencies of 18.1%, 27.4% and 14.9%, respectively. Their two-photon absorption (2PA) properties have been investigated using the open-aperture Z-scan technique, and the values of the 2PA cross section at 800 nm for 3a–c are 1363 GM, 413 GM and 5782 GM, respectively. Their excellent 2PA properties and solid quantum efficiencies pave the way for their potential use in biophotonic and optoelectronic applications.

Robust and highly efficient blue light-emitting hosts based on indene-substituted anthracene

Two new unsymmetrically indene-substituted 10-naphthylanthracene derivatives, 9-(4-(1,1′-dimethylinden-3-yl)phenyl)-10-(1-naphthyl)anthracene (DMIP-1-NA) and 9-(4-(1,1′-dimethylinden-3-yl)phenyl)-10-(2-naphthyl)anthracene (DMIP-2-NA), were easily synthesized. Both of them show intense fluorescence and good thermal stability. Three-layer organic light-emitting devices (OLEDs) using these anthracene derivatives as blue host materials and diphenyl-[4-(2-[1,1′;4′,1′′]terphenyl-4-yl-vinyl)-phenyl]amine (BD-1) as the dopant emitter have been fabricated. Highly efficient and color stable OLEDs were achieved under the range of doping concentration from 3% to 7%. A further optimized device structure based on DMIP-2-NA exhibited a maximum power efficiency of 8.39 lm W−1 (7.6 cd A−1 at 2.90 V) with a pure blue emission at CIEx,y coordinates of (0.14, 0.18).

Highly sensitive determination of low-level water content in organic solvents using novel solvatochromic dyes based on thioxanthone

Two thioxanthone-based fluorescent probes exhibited prominent solvatofluorochromism, and they were further found to be useful as fluorescence indicators for the qualitative and quantitative detection of low-level water content in various solvent media.

Syntheses and nonlinear absorption of novel unsymmetrical cyanines

A new synthetic strategy for the generation of methine cyanine dyes with asymmetrical structures has been developed based on a modified Vilsmeier reaction and the condensation reaction of indoline derivatives with organic pyridinium iodide or 4-diphenylamino-benzaldehyde. The nonlinear absorption of some cyanines has been measured using the Z-scan technique.

Highly sensitive detection of low-level water content in organic solvents and cyanide in aqueous media using novel solvatochromic AIEE fluorophores

A great deal of effort has been devoted to develop easy-to-use fluorescent probes for detecting analytes due to their advantages in the field of chemo- and bio-sensing. Herein, two novel 2,2′-biindenyl-based derivatives BDM and BDBM containing dicyanovinyl groups have been designed and synthesized, and are shown to possess the remarkable dual properties of solvatochromism and aggregation-induced emission enhancement (AIEE). Importantly, both of them are found to serve as fluorescent indicators for the qualitative and quantitative detection of low-level water in organic solvents. Meanwhile, both BDM and BDBM emit yellowish orange and orange fluorescence, respectively, in their aggregated states. Furthermore, with dicyanovinyl groups as the recognition sites, both compounds can act as colourimetric and fluorescent sensors for highly sensitive and selective detection of cyanide in aqueous media, and the apparent response signals can be observed by the naked eye even in the presence of various interference anions, promising practical applications for detecting cyanide in drinking water. Besides, optical spectroscopic techniques, NMR titration measurements, and density functional theory calculations are conducted to rationalize the sensing mechanisms of the two probes.

Novel hole transport materials based on N,N′-disubstituted-dihydrophenazine derivatives for electroluminescent diodes

A series of novel hole transport materials for organic light-emitting diodes (OLEDs) based on 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine were synthesized and characterized by 1H NMR and 13C NMR, mass spectrometry and single crystal structure analysis methodologies. The crystal structures of three selected molecules reveal large dihedral angles between different functional units. The electro-optical properties of the materials were examined by UV-vis absorption, photoluminescence spectroscopy and cyclic voltammetry. The HOMO of the materials were between 4.83–5.08 eV, indicating a good match between the HOMO of indium tin oxide (ITO) and the HOMO of light-emitting layer, which renders the promising candidates as hole transport materials for organic light-emitting devices. In terms of the device with the structure of ITO/HTM (60 nm)/Alq3 (50 nm)/LiF (1 nm)/Al (200 nm), the device b using N,N-diphenyl-4′-(14-phenyldibenzo[a,c]phenazin-9(14H)-yl)-[1,1′-biphenyl]-4-amine presented a maximum luminance of 17 437 cd m−2 at 10.7 V and kept a high current efficiency (the maximum current efficiency is 2.25 cd A−1) at a high current density (>500 mA cm−2), which illustrates the exploited material possesses good hole transport and stable properties.

Novel polymeric metal complexes based on bis-(8-hydroxylquinolinol)

Novel polymeric metal complexes based on bis(8-hydroxyquinolinol) were synthesized by a concise route. Substitution effects on their fluorescence spectra in the solution and in the solid state were tested and discussed preliminarily.