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A NIR strong absorbing molecule was constructed by taking the structural advantages of a quinoid and diketopyrrolopyrrole, with an absorption maximum of up to 1039 nm and hole and electron mobilities up to 0.19 and 0.2 cm2 V−1 s−1, respectively.

New semiconducting D–A molecules with a fused tetrathiafulvalene–naphthalene diimide framework show near-infrared absorptions and emissions with maxima up to 1062 nm and quantum yields up to 1.64%.

Diketopyrrolopyrrole (DPP) and its derivatives are commercially used dyes that have drawn great attention in recent years for applications in organic electronic/optical materials. These material studies cannot progress without further developments in the syntheses of the DPP family of molecules. In this review, recent progress in the syntheses of DPP derivatives is summarized in detail as well as the structure–property relationships of the derivatives, including the syntheses of DPP cores, N-functionalization reactions, and π-extensions on and along the DPP cores. Finally, existing problems and future perspectives of DPP-based derivatives are also discussed.

Organic and organometallic π-conjugated molecules with inherent nonlinear optical (NLO) responses have attracted great interest due to their controllable properties via rational structure modifications. However, most of the state-of-the-art materials such as porphyrins, phthalocyanines, and diacetylenes exhibit NLO responses at visible-light regions. Recently, diketopyrrolopyrrole (DPP) based donor–acceptor (D–A) type π-conjugated copolymers have been found to exhibit NLO responses which can reach up to 1064 nm. However, the design rationality of the structure toward NLO properties is not well understood. Herein, four alternating DPP-based copolymers are constructed by using the electron donors of 2-phenylpyridine for P1, 2-thienylpyridine for P2 and their Pt(II)-incorporated moieties for P1Pt and P2Pt. All copolymers display intense intramolecular charge transfer (ICT) processes, and the ICT absorption can be extended to the near-infrared (NIR) region due to the strong D–A interaction of the π-conjugated backbone. The variation tendency of optical bandgaps estimated from the onset of ICT absorption is P1 (1.60 eV) > P1Pt (1.56 eV) > P2 (1.47 eV) > P2Pt (1.44 eV). Open- and closed-aperture Z-scan experiments disclosed that all copolymers exhibit broadband (532 and 1064 nm) NLO properties due to the synergistic effect of excited state absorption and the ICT process upon excitation of 8 ns as well as 25 ps laser pulses. Pt(II)-incorporation can promote or switch the NLO properties due to the efficient triplet-state absorption introduced by the heavy-atom effect. The improvement of the NLO properties is of the order P1 < P1Pt < P2 < P2Pt, which is consistent with the decreasing trend of the copolymer bandgaps. These results will provide guidelines for the rational design of materials toward broadband NLO responses and advanced applications.

A highly selective and red emissive fluorescent probe (HCyNB) for penicillin G amidase (PGA) has been prepared in a simple two-step process. After enzymatic reaction, HCyNB showed a fast response to PGA and afforded a light-up red fluorescence assay of PGA with a detection limit of 0.067 U L−1, without interference from other biologically-relevant species and enzymes, including ROS. The easy synthesis, fast response, good sensitivity, remarkable selectivity and pH independence render HCyNB an outstanding tool for bioimaging of endogenous PGA in penicillinase-producing Bacillus subtilis.

Based on one single AIE-doped photonic-structured polyionic liquid sphere, a novel customizable virtual sensor array system was developed., By simultaneously exploiting the unique properties of ionic liquids and aggregation-induced emission (AIE) luminogens, as well as photonic structures, a novel customizable sensing system for multi-analytes was developed based on a single AIE-doped poly(ionic liquid) photonic sphere. It was found that due to the extraordinary multiple intermolecular interactions involved in the ionic liquid units, one single sphere could differentially interact with broader classes of analytes, thus generating response patterns with remarkable diversity. Moreover, the optical properties of both the AIE luminogen and photonic structure integrated in the poly(ionic liquid) sphere provide multidimensional signal channels for transducing the involved recognition process in a complementary manner and the acquisition of abundant and sufficient sensing information could be easily achieved on only one sphere sensor element. More importantly, the sensing performance of our poly(ionic liquid) photonic sphere is designable and customizable through a simple ion-exchange reaction and target-oriented multi-analyte sensing can be conveniently realized using a selective receptor species, such as counterions, showing great flexibility and extendibility. The power of our single sphere-based customizable sensing system was exemplified by the successful on-demand detection and discrimination of four multi-analyte challenge systems: all 20 natural amino acids, nine important phosphate derivatives, ten metal ions and three pairs of enantiomers. To further demonstrate the potential of our spheres for real-life application, 20 amino acids in human urine and their 26 unprecedented complex mixtures were also discriminated between by the single sphere-based array.

A new selective and sensitive fluorescence turn-on detection of ClO- is reported by taking advantage of the specific reaction between a 1-methyl-1,2-dihydropyridine-2-thione unit and ClO- and the aggregation induced-emission (AIE) behavior of the tetraphenylethylene unit.

Conjugated D–A polymers with high charge mobilities have received increasing attention in recent years. In this paper, we report a simple, but efficient approach to improve the charge mobilities of conjugated polymers by partial replacement of branching alkyl chains with linear ones. With this strategy in mind, we designed and investigated three new DPP-quaterthiophene terpolymers PDPP4T-1, PDPP4T-2 and PDPP4T-3 containing both linear (n-dodecane) and branching (2-decyltetradecyl) alkyl chains with different ratios. On the basis of GIWAXS data, interchain packing order is improved for terpolymers PDPP4T-1, PDPP4T-2 and PDPP4T-3, in comparison with PDPP4T with only branching alkyl chains. The incorporation of linear alkyl chains can affect the interchain packing mode, and PDPP4T-3 with more linear alkyl chains among the three terpolymers adopts the edge-on chain arrangement on the substrate. Field effect transistor measurements indicate that PDPP4T-1, PDPP4T-2 and PDPP4T-3 exhibit higher hole mobilities than PDPP4T. Moreover, the hole mobilities increase in the following order: PDPP4T-1 < PDPP4T-2 < PDPP4T-3 by increasing the content of linear alkyl chains in these terpolymers. The thin film mobility of PDPP4T-3 can reach 6.1 cm2 V−1 s−1, which can be further increased to 9.1 cm2 V−1 s−1 after incorporating NMe4I.

In this work, a conjugated polymer PNV is developed, linking naphthalene diimide with a vinyl linkage. Owing to the C–H⋯O hydrogen bond between the carbonyl and the vinyl, PNV exhibits a high red emission with a quantum yield of 33.4% in the solid state while it shows n-type properties with an electron mobility up to 1.5 × 10−3 cm2 V−1 s−1 in organic field effect transistors, simultaneously.

A fast and sensitive method was established for an in-solution selection of cancer cell-targeting peptides at "single-residue resolution" by using the switchable fluorescence of tetraphenylethylene. The selected peptides have potential for biomarker tracing and can be used for targeted delivery of different cargos into living cancer cells.

Two-photon excited fluorescence microscopy and nanoparticle-assisted photodynamic therapy (PDT) are two important areas in biomedical research, and their combination can be more beneficial. A type of red emissive photosensitizer (PS) with aggregation-induced emission (AIE) features, which is called tetraphenylethylene (TPE-red), was synthesized and further encapsulated with poly(styrene-co-maleic anhydride) (PSMA) to form nanoparticles. Two-photon fluorescence, as well as two-photon excited reactive oxygen species (ROS) generation by TPE-red–PSMA nanoparticles, was characterized. A large two-photon absorption cross-section was observed at 1040 nm with a femtosecond (fs) laser. PDT via two-photon excitation was well realized on tumor cells, using TPE-red–PSMA nanoparticles as PSs under 1040 nm fs laser excitation. Based on our study, we believe that two-photon excited PDT with AIE-active PSs has great potential applications in deep tissue imaging-guided therapy.

An AIE based tetraphenylethylene derivative (MOTIPS-TPE) with a pyridinium pendant was synthesized for light-up sensing of F− in aqueous solution without additives. The fluoride ion promoted cleavage reaction gave MOTIPS-TPE high selectivity toward F− over other common anions. Moreover, MOTIPS-TPE can be used to monitor F− in living HeLa cells.

Three conjugated D–A terpolymers PBPD1, PBPD2, and PBPD3 with the Pechmann dye-derived electron acceptor and dithienyl-diketopyrrolopyrrole as co-acceptors are presented. Their HOMO/LUMO energies and absorptions can be tuned by varying the ratios of two acceptors. Importantly, HOMO energies of these terpolymers are lowered by increasing the content of the Pechmann dye-derived electron acceptor in the conjugated backbones. The thin blend films of PBPD1, PBPD2, and PBPD3 with PC71BM have been tested as active layers for polymer solar cells. The blend of PBPD1:PC71BM shows a high power conversion efficiency of up to 5.21%, which is higher than that with the blend of the dithienyl-diketopyrrolopyrrole-based polymer without the Pechmann dye-derived electron acceptor and PC71BM. In addition, the neat thin films of PBPD1, PBPD2, and PBPD3 exhibit ambipolar semiconducting properties with hole and electron mobilities up to 0.604 cm2 V−1 s−1 and 0.225 cm2 V−1 s−1.

In order to demonstrate the influence of structural fine-tuning on bandgap and semiconductor performance of π-conjugated polymer materials, three new diketopyrrolopyrrole (DPP) based copolymers P1, P2 and P3 with monomers, i.e., 2-phenylpyridine, 2-(thiophen-2-yl)pyridine and 2-(thiophen-2-yl)thiazole, respectively, have been synthesized using a typical Suzuki cross-coupling polycondensation. The DFT calculations demonstrate that polymer P3 displays high backbone coplanarity in comparison to polymers P1 and P2. Absorption spectra results reveal that P3 exhibits a remarkable red-shifted absorption profile, narrow band gap and broad absorption. The thin film FET measurements show that P3 possesses the highest hole mobility (μh) up to 1.25 cm2 V−1 s−1 and on/off (Ion/off) ratio as high as 108. Those results demonstrate that the fine-tuning of the π-conjugated backbone can significantly affect the band gaps and coplanarities, and ultimately improve the semiconducting performances.

In this paper we report two n-type polymeric acceptors P1 and P2 based on imide/amide-derivatives (PDI, NDI and DPP). P1 and P2 exhibit very different optical properties which may be related to the different molecular configuration and polymeric crystallinity. All polymer solar cells were fabricated with conventional configuration based on polymeric donor PBDTTT-C-T and P1/P2. Results reveal that devices based on P1 show the best performance with a PCE of 2.01%, a V-OC of 0.68 V, a J(SC) of 7.06 mA cm 2 and a FF of 41.78%, which is attributed to the appropriate energy levels, relatively high electron mobility and preferable micro-phase separation. The poor performance for P2 ( PCE = 0.30%) was mainly ascribed to its extremely low J(SC) which was probably caused by the small HOMO energy level difference between donor and P2.

Chemotherapeutics specifically targeting cancer cells without damaging healthy cells is the long-awaited goal of cancer treatment. In this paper, a series of nanoparticles (NanoTPES 1–4) assembled from pyridinium-substituted tetraphenylethylene salts were synthesized and investigated both in vitro and in vivo for this purpose. By changing the counter anions, NanoTPES 1–4 exhibit tunable emission colors, sizes and surface charges. NanoTPES 2 and 3 with tetraphenyl borate and tetra(4-chlorophenyl) borate as the respective anions selectively imaged and targeted mitochondria in cancer cells. Accordingly, these two nanoparticles specifically kill cancer cells with minimal effect on normal cells. Such selective cytotoxicity was attributed to the change of membrane potential and inhibition of ATP synthesis in the mitochondria of cancer cells. Furthermore, both NanoTPES 2 and 3 exhibited efficient tumor accumulation and tumor growth inhibition in vivo, with negligible systemic toxicity.

Three new conjugated D–A terpolymers PADPP1, PADPP2 and PADPP3, which contain diketopyrrolopyrrole (DPP) as electron acceptors and thiophene/anthracene as electron donors, are described. In comparison with PDPP3T which contains just DPP and thiophene units, the DPP moieties are partially replaced with anthracene units in PADPP1, PADPP2 and PADPP3. The HOMO/LUMO levels of PADPP1, PADPP2 and PADPP3 are slightly enhanced in comparison with those of PDPP3T. Moreover, the incorporation of the anthracene units into the backbones leads to the formation of nanofibrils with an appropriate width within the blending thin films of PADPP2 with PC71BM. The short circuit currents (JSC) of the photovoltaic cells with blends of PADPP1, PADPP2 and PADPP3 with PC71BM are higher than those with the PDPP3T/PC71BM blend. As a result, PADPP1, PADPP2 and PADPP3 display better photovoltaic performances than PDPP3T after blending each polymer with PC71BM under the same conditions. The PCE of the photovoltaic cell of the PADPP2/PC71BM blending thin film at a weight ratio of 1 : 2 as the active layer can reach 6.24%.

The efficiency of the intersystem crossing process can be improved by reducing the energy gap between the singlet and triplet excited states (ΔE ST), which offers the opportunity to improve the yield of the triplet excited state., The efficiency of the intersystem crossing process can be improved by reducing the energy gap between the singlet and triplet excited states (ΔE ST), which offers the opportunity to improve the yield of the triplet excited state. Herein, we demonstrate that modulation of the excited states is also an effective strategy to regulate the singlet oxygen generation of photosensitizers. Based on our previous studies that photosensitizers with aggregation-induced emission characteristics (AIE) showed enhanced fluorescence and efficient singlet oxygen production in the aggregated state, a series of AIE fluorogens such as TPDC, TPPDC and PPDC were synthesized, which showed ΔE ST values of 0.48, 0.35 and 0.27 eV, respectively. A detailed study revealed that PPDC exhibited the highest singlet oxygen efficiency (0.89) as nanoaggregates, while TPDC exhibited the lowest efficiency (0.28), inversely correlated with their ΔE ST values. Due to their similar optical properties, TPDC and PPDC were further encapsulated into nanoparticles (NPs). Subsequent surface modification with cell penetrating peptide (TAT) yielded TAT–TPDC NPs and TAT–PPDC NPs. As a result of the stronger singlet oxygen generation, TAT–PPDC NPs showed enhanced cancer cell ablation as compared to TAT–TPDC NPs. Fine-tuning of the singlet-triplet energy gap is thus proven to be an effective new strategy to generate efficient photosensitizers for photodynamic therapy.

We report the design and synthesis of a red fluorescent AIE light-up probe for selective recognition, naked-eye detection, and image-guided photodynamic killing of Gram-positive bacteria, including vancomycin-resistant Enterococcus strains.

A new sensitive fluorescence turn-on detection of gamma-radiation is reported by taking advantage of aggregation induced-emission (AIE) behaviour of the tetraphenylethylene unit and the cascade radiochemical and protonation reactions.

In this paper we report two DPP-based conjugated molecules DPPBT and DPPTT in which the respective electron withdrawing moieties 2,1,3-benzothiadiazole and thiazolo[5,4-d]thiazole are flanked by two DPP moieties. For comparison, DPPBZ containing 1,4-diethynylbenzene and two DPP moieties were synthesized. HOMO/LUMO energies of DPPBT, DPPTT and DPPBZ were estimated on the basis of cyclic voltammetric data. Owing to the fact that LUMO energies of DPPBT and DPPTT were lowered to ca. −3.5 eV, thin films of both DPPBT and DPPTT exhibit ambipolar semiconducting properties under N2 atmosphere with hole and electron mobilities up to 0.25 cm2 V−1 s−1 and 0.09 cm2 V−1 s−1, respectively. In comparison, thin film of DPPBZ just shows p-type semiconducting property. Notably, ambipolar semiconductors with relatively high carrier mobility are rarely reported for DPP-containing small conjugated molecules. Alternatively, both DPPBT and DPPTT can function as electron donors for photovoltaic materials. Thin films of DPPTT:PC71BM and DPPBT:PC71BM at a weight ratio of 1 : 1 exhibit PCEs of 4.18% and 2.44%, respectively, with VOC higher than 0.95 V.

New conjugated D–A molecules BTBID, BFBID, TBID, 2BIDBDT and 2BIDBT with (E)-[4,4′-biimidazolylidene]-5,5′(1H,1′H)-dione (BID) moieties are reported. Based on the respective absorption spectra and redox potentials, their HOMO (−5.30 to −5.52 eV), LUMO (−3.81 to −3.86 eV) and bandgaps (1.46–1.68 eV) were estimated. The HOMO energies and bandgaps could be effectively modulated by extending the conjugation length. The crystal structure of BTBID was presented. Intermolecular electron donor–donor interactions are present, but the intermolecular electron donor–acceptor interactions do not exist within the crystal. OFETs with thin-films of these conjugated molecules were fabricated with conventional solution-processed techniques, and p-type semiconducting properties were observed. Compared to BTBID and BFBID, thin-films of TBID, 2BIDBDT and 2BIDBT exhibit relatively high hole mobilities, reaching 0.037 cm2 V−1 s−1, 0.022 cm2 V−1 s−1 and 0.020 cm2 V−1 s−1 after thermal annealing, even though the thin-films of 2BIDBDT and 2BIDBT possess poor morphologies.

A new naphthalene diimide (NDI) derivative 4NH2-NDI was synthesized and investigated. The introduction of four amino groups at core position endows 4NH2-NDI with a high HOMO energy (−4.87 eV). The organic field effect transistor (OFET) results reveal that 4NH2-NDI behaves as a p-type semiconductor with a rather low hole mobility of 8.2 × 10−5 cm2 V−1 s−1. However, its hole mobility can be enhanced significantly after doping with N,N-dihexyl naphthalene diimide (DHNDI). More interestingly, the blend thin films of 4NH2-NDI and DHNDI exhibit ambipolar behavior based on the respective transfer and output characteristics measured in an inert atmosphere, and hole and electron mobilities can reach 0.01 cm2 V−1 s−1 and 0.001 cm2 V−1 s−1, respectively, when the molar ratio of 4NH2-NDI and DHNDI is 1 : 3.

A simple synthetic approach to dithiazole-fused naphthalene diimides 1 and 2 from 2,6-dibromoNDI (2BrNDI) was described. Note that the synthesis did not involve any metallic catalysts. Based on their cyclic voltammograms, the LUMO energies of 1 and 2 were estimated to be −3.99 eV and −3.98 eV, respectively, being lower than that of unsubstituted NDI. Thin films of 1 and 2 show n-type semiconducting behaviors. OFETs of 1 exhibit electron mobility up to 0.15 cm2 V−1 s−1 with high on/off ratio (under ambient conditions) after annealing.

In this feature article we summarize the recent developments of stimuli responsive gels based on low molecular weight gelators (LMWGs) for which the gel-sol transitions can be triggered by other stimuli besides heating. These include gels responsive to redox reactions and light irradiations. Chemoresponsive gels are also introduced, including those for which the gel-sol transitions can be induced by reactions with neutral molecules and those for which the gel strength is improved following the addition of neutral molecules. Perspectives for such stimuli responsive gels are discussed with regard to their potential applications and remaining challenging issues.

A new ratiometric fluorescence detection of heparin is reported with the ensemble of 1 and 2. This method is based on the respective ACQ (aggregation-caused quenched emission) and AIE (aggregation-induced emission) features of anthracene and tetraphenylethene. DLS, CLSM and fluorescent spectral investigations suggest that the variation of the fluorescence intensity ratio I(497)/I(421) is due to the formation of aggregates of 1 and 2 with heparin. Moreover, this ratiometric fluorescence method can be used to distinguish heparin from its analogues (HA, Dex). In order to demonstrate the practical utilization of this ratiometric fluorescence method, the fluorescence spectra of the ensemble of 1 and 2 were measured in the presence of serum, and the results indicate that it is possible to eliminate the interferences from other biomolecules by either subtracting the background fluorescence intensities or lowering the pH values of the sample solutions.

A resorufin derivative with a DBS group (probe 1) was designed and investigated for the detection of acetylcholinesterase (AChE) and inhibitor screening. The new assay is based on cascade enzymatic and chemical reactions of ATC, AChE and probe 1, and it can be carried out in a dual-signal detection mode. Moreover, the results show that probe 1 can be used for cell fluorescence staining.

Among the reported organic n-type semiconductors, naphthalene diimide (NDI) derivatives have received increasing attention. In this paper, we report four non-symmetric core-expanded NDI derivatives 1–4. Electrochemical, absorption spectral and theoretical calculation studies show that LUMO energies of 1–4 are lower than that of parent NDI without substitution. OFET devices based on thin films of 1–4 which can be easily solution-processed are fabricated with conventional techniques and they show n-type semiconducting behaviours. Moreover, the performance of OFET devices of 1–4 can be significantly improved by annealing their thin films. OFETs of 3 exhibit electron mobility up to 0.17 cm2 V−1 s−1 with high on/off ratio (under ambient conditions) after annealing.

In this paper, we report four new core-extended NDI molecules 1, 2, 3 and 4. 1 and 2 entail two benzene rings and two naphthalene rings, respectively; 3 and 4 contain benzene and naphthalene rings as well as 2-(1,3-dithiol-2-ylidene)malonitrile groups. All of them can be easily synthesized with acceptable yields. HOMO/LUMO energies of 1, 2, 3 and 4 were −5.66 eV/−3.93 eV, −5.73 eV/−3.91 eV, −5.88 eV/−4.22 eV and −5.89 eV/−4.23 eV, respectively. OFETs with thin-films of 1, 2, 3 and 4 were successfully fabricated with conventional techniques. Thin-films of 1 and 2 exhibit ambipolar semiconducting properties under N2 atmosphere with relatively balanced hole and electron mobilities, which can further increase after annealing; hole and electron mobilities reach 0.047 and 0.016 cm2 V−1 s−1, respectively for the thin-film of 2 after annealing at 140 °C. Moreover, two identical ambipolar transistors with thin films of 2 were combined into an inverter circuit with a gain of 11. 3 and 4 behave as n-type semiconductors in air, and the electron mobility can reach 0.22 cm2 V−1 s−1 for the thin-film of 3 with an Ion/off of 106 after annealing at 120 °C. XRD and AFM studies are also presented for understanding the variation of carrier mobilities of thin-films of 1, 2, 3 and 4 after annealing at different temperatures.

Four new alternating D–A polymers (P1–P4) with (E)-[4,4′-biimidazolylidene]-5,5′(1H,1′H)-dione (BID) as electron accepting moieties were synthesized and characterized. Based on GPC (gel permeation chromatography) data, Mws of P1–P4 are relatively high ranging from 11.8 to 14.7 kg mol−1 with polydispersities of 1.8–1.9. Thin-films of P1–P4 show broad and strong absorptions up to 950 nm. HOMO (−5.11 eV to −5.32 eV) and LUMO (−3.71 eV to −3.81 eV) energies as well as band gaps (1.40 eV to 1.53 eV) were determined based on their onset redox potentials and absorption spectra. Field-effect transistors with thin-films of P1–P4 were successfully fabricated with conventional techniques. The results reveal that thin-films of P1 and P2 exhibit relatively high hole mobilities of up to 6.6 × 10−3 cm2 V−1 s−1.

New conjugated electron donor–acceptor molecules with tetrathiafulvalene (TTF) fused-naphthalene diimide frameworks (1–6) are synthesized and investigated. The NDI cores are flanked by TTF and 2-(1,3-dithiol-2-ylidene)malonitrile moieties within 1–3, whereas compounds 4–6 contain two TTF moieties. Based on cyclic voltammetric and absorption spectral studies, the LUMO and HOMO energies of 1–3 are estimated to be ca. −4.3 eV and ca. −5.1 eV, and those of 4–6 are ca. −4.1 eV and ca. −5.0 eV, respectively. These values are consistent with theoretical calculations. Thin films of 1–6 are easily prepared with the spin-coating technique and the resulting OFETs are successfully fabricated with conventional procedures. The OFETs results reveal that compounds 1–3 behave as ambipolar semiconductors and 4–6 as p-type semiconductors. Among 1–3, compound 3 exhibits relatively high hole and electron mobilities in air, reaching 0.03 and 0.003 cm2 V−1 s−1, respectively, after annealing at 160 °C. The OFET based on a thin film of 5 shows the best performance with μh = 0.31 cm2 V−1 s−1, Ion/off = 104 among compounds 4–6 after annealing at 160 °C. The thin films of 1–6 are investigated with XRD and AFM, and the data can well interpret the variation of carrier mobilities of 1–6 after annealing. Moreover, the influences of alkyl chains in 1–6 on the intermolecular arrangements and carrier mobilities are also discussed.

A new selective and sensitive fluorescence turn-on detection of CN(-) is reported by taking advantage of aggregation induced-emission (AIE) behavior of tetraphenylethylene units and the nucleophilic attack of CN(-) on the indolium group in compound 1.

A facile and convenient method for the reduction of graphite oxide (GO) to reduced GO (RGO) is established by taking advantage of the electron transfer from TTF to GO in the presence of metal ions (Sc3+/Pb2+). The resulting RGO is characterized by FT-IR, XPS and Raman spectroscopy. The room-temperature conductivity of RGO can reach 1.5 S m−1. Moreover, the reduction degree of RGO in terms of the Raman D/G intensity ratio and the conductivity is found to be dependent on the oxidation potentials of TTF derivatives.

The fluorescence of tetra(4-pyridylphenyl)ethylene (1) can be switched on significantly by the synergistic interactions of Hg(2+) and HSO(4)(-) based on a new aggregation mechanism for tetraphenylethylene molecules.

A new C60-based low-molecular weight gelator (LMWG 1) with a L-glutamid-derived lipid unit was synthesized and characterized. LMWG 1 can gel toluene, p-xylene and benzene. Moreover, its gelation ability can be further enhanced by addition of an exTTF derivative (compound 2), for which the intermolecular interaction between the C60 unit in 1 and the exTTF unit in 2 is responsible based on the absorption and NOE difference 1H-NMR spectral studies. Additionally, gelation-induced CD signals are observed for the gel with LMWG 1 and that of LMWG 1 doped with compound 2. Further studies indicate that the self-assembly structures of LMWG 1 in the gel phases can be modulated by the addition of compound 2. In addition, the self-assembly of LMWG 1 in DMSO leads to spherical particles of several microns in size, and the surfaces of these spherical particles are hierarchically structured with nano-fibers. Moreover, the thin-film of spherical particles exhibits water-repellent hydrophobicity.

Among the reported organic n-type semiconductors naphthalene diimide (NDI) derivatives have received more and more attention. In this paper, we report two sulfur-rich expanded NDI derivatives 1 and 2 containing 1,3-dithiole-2-thione-4,5-dithiolate and 1,3-dithiole-2-one-4,5-dithiolate units, respectively. Electrochemical, absorption, spectral and theoretical calculation studies show that LUMO energies of 1 and 2 are lower than that of a typical NDI without functional substitution. OFET devices based on thin-films of 1 and 2 which can be easily solution-processed are fabricated with conventional techniques. The performance of OFET devices of 1 and 2 can be significantly improved by fast annealing (about 30 s) their thin-films in air, with high on/off ratios (106–107) and relatively high electron mobilities of up to 0.05 and 0.04 cm2 V−1s−1, respectively.

A facile and convenient fluorescence detection of gamma-ray radiation is reported. This is based on the ensemble of silole 1 and polymer 2, by taking advantages of AIE (aggregation-induced emission) behavior of silole compounds and the fact that polymers with –SO2groups in the main chain can be degraded upon gamma-ray radiation. The fluorescence intensity of the ensemble of silole 1 and polymer 2 decreases gradually after exposure to increasing dose of gamma-ray radiation. The detection of gamma-ray radiation with silole 1 and polymer 2 can be performed at ambient conditions and gamma-ray radiation as low as 0.13 kGy dose can be successfully detected.

Gold nanoparticles (Au-NPs) with negative charges aggregate in the presence of Arg(6) due to electrostatic interactions resulting in the red-shift of the plasmon absorption. But, after incubation of Arg(6) with trypsin the aggregation of Au-NPs can be prohibited. Accordingly, a newly designed-Au-NPs based colorimetric assay method for trypsin activity is established. Trypsin with a concentration as low as 1.6 ng mL(-1) can be assayed with this new colorimetric assay. This colorimetric label-free assay for trypsin can be performed in aqueous solution and both Au-NPs and Arg(6) are easily accessible. Thus, this assay method is useful for screening inhibitors of trypsin.

As essential enzymes in the body, monoamine oxidases (MAOs), including MAO-B, help maintain the proper balance of neurotransmitters and other dietary and biogenic amines. Thus, development of convenient and continuous assays for MAO-B and its inhibitor-screening is highly desirable since the inhibitors have implications for therapeutics for many brain diseases. In this paper, we report a direct continuous fluorescence turn-on assay for MAO-B and its inhibitor-screening with the ensemble of silole 1, heptylamine and HSO(3)(-), which are either easily accessible or commercially available. Fluorescent spectral investigations show that this fluorometric assay can be performed continuously in aqueous solution and MAO-B of concentrations as low as 0.25 microg/mL can be analyzed. Moreover, the ensemble of silole 1, heptylamine, HSO(3)(-) and MAO-B can be employed to screen the inhibitors of MAO-B.

New fluorescent sensors have been developed, utilizing the aggregation-induced emission (AIE) attribute of silole and tetraphenylethene luminogens. In this feature article, we briefly summarize recent progress in the development of AIE-based bio/chemosensors for assays of nuclease and AChE activities, screening of inhibitors, and detection of various analytes including charged biopolymers, ionic species, volatile and explosive organic compounds.

A new silole derivative with an ammonium group was designed and studied with a view to developing a convenient fluorescence turn-on assay for heparin by taking advantage of the aggregation-induced enhanced emission (AIE) feature of silole (silacyclopentadiene) molecules.

New selective chemodosimeters for Hg(II) ion based on 1,3-dithiole-2-thione derivatives containing an anthracene unit are described.