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Accessing high-order multiphoton excited fluorescence (H-MPEF) materials is challenging yet and needs complicated synthesis procedures. In this study, we successfully assembled plasmonic Au nanorods (Au NRs) with multiphoton responsive metal-organic frameworks (MOFs), resulting in a significant several-fold enhancement of H-MPEF. The extent of multiphoton enhancement was found to be strongly dependent on the degree of overlap between the multiphoton excitation wavelength of MOFs and the localized surface plasmon resonance absorbance of Au NRs, indicating the importance of plasmon-induced resonance energy transfer. Besides, plasmon-induced hot electron transfer played a vital role in enhanced multiphoton activity as well. Notably, the optimum H-MPEF enhancement occurs at the second near-infrared (NIR-II) region, which provides a promising platform for fluorescent bioimaging. Our findings provide a feasible and practical method to fabricate optimized H-MPEF materials for biological imaging using tissue-penetrating NIR-II light. [ABSTRACT FROM AUTHOR]

A novel organic/inorganic nanohybrids which consisted of ligand L (L = 2-[(2-hydroxy-ethyl)-(4-[2,2′;6′,2″] terpyridin-4′-yl-phenyl)-amino]-ethanol), an optical terpyridine derivative and ZnS nanoparticles (NPs), had been prepared through a solution-phase synthesis technique. The intermolecular interactions at the interface between ZnS and the ligand components were analyzed by FT-IR, far-IR, UV-Vis absorption spectroscopy, XRD and TEM. Particular properties had been shown by fluorescence spectra, fluorescence lifetime, Raman spectrum, aggregation emission and non-linear optical response. The results indicated that the nano-composite L-ZnS NPs had an obvious aggregation-induced emission in ethanol/ n-hexane mixtures, and had larger two-photon absorption (TPA) when compared to the free ligand L. The data for the TPA cross-section value ( σ = 16,247.8 GM), nonlinear refractive index ( γ = 4.46 × 10 cm W) and the third order nonlinear polarizability [Im χ (esu) = 1.13 × 10] were measured and discussed. Meanwhile, due to the laser irradiation induced charge transfer from the ligand to ZnS NPs, the composite could be potentially applied in vitro and in vivo cellular imaging. [ABSTRACT FROM AUTHOR]

Benefiting from their unique delocalized electronic structure, conjugated polymer-based semiconductors are widely applied in the fields of organic electronics, sensors, and biomedical applications. However, the photocatalytic properties of conjugated polymers have been seldom studied because of their unsuitable band structures. Herein, we creatively demonstrate that the band structures of conjugated polymers are strongly related to their degree of polymerization (DP), offering an effective strategy for the design of metal-free photocatalysts with tunable light absorption properties. Taking poly(3- hexylthiophene) (PHT) as an example, we show that PHT nanofibers with a suitable DP are a novel visible light-driven photocatalyst, which can readily convert molecular oxygen into superoxide ions. Benefiting from the high selectivity of the generated superoxides, the PHT nanofibers display outstanding activity for the aerobic oxidation of amines into imines with nearly 100% conversion and selectivity. This study offers a new strategy for the design of advanced conjugated polymer-based photocatalysts. [ABSTRACT FROM AUTHOR]

A hydrophilic polypyrrole/tellurium (PPy/Te) nanocomposite was synthesized by a facile approach in which HTeO was used as the oxidizing agent of pyrrole and then the elemental Te formed in situ catalyzed the polymerization of pyrrole. The morphology and structure of the products were characterized by a series of testing technology. The electrochemical property and impedance of the PPy/Te nanocomposite were studied by cyclic voltammetry and electrochemical impedance spectroscopy, respectively. Significantly, the charge-discharge measurement results show that the PPy/Te nanocomposite has high specific capacitance (2488 F/g, at 2 A/g) and good cyclability. [ABSTRACT FROM AUTHOR]

The cobalt sulfide/graphene oxide (CoS/GO) nanocomposite was synthesized by a simple hydrothermal reaction. The products as-synthesized were characterized by XRD, SEM, TEM, BET-BJH and TG. The electrochemical property and impedance of the CoS/GO nanocomposite were studied by cyclic voltammetry and EIS analysis, respectively. The results show that the presence of the GO enhances the electrode conductivity, and then improves the capacitance property of the CoS/GO nanocomposite. The galvanostatic charge/discharge measurement results show that the CoS/GO nanocomposite has a high specific capacitance (550 Fg) and long cycle life (over 1 000 cycles). [ABSTRACT FROM AUTHOR]

The combination of organic conducting polymer with inorganic semiconductor is one of the most important topics in developing photoelectric materials. In this work, bouquet-like polythiophene/tellurium (PTh/Te) nanocomposite was synthesized via the redox reaction of HTeO and thiophene. The formation mechanism and effect factors of PTh/Te nanocomposite were discussed. It was found that the elemental Te formed in situ promoted the polymerization of thiophene, and the remainder HTeO molecules adsorbed on the PTh chains made the nanocomposite soluble. The Z-scan test results show that the PTh/Te nanocomposite has a large two-photon absorption (TPA) cross-section and nonlinear optical (NLO) absorption coefficient. [ABSTRACT FROM AUTHOR]

In this letter, aggregation from two-photon absorption (2PA) molecules in living cells were firstly observed and the related aggregation induced emission (AIE) properties were investigated as a cell tracer for L ((Z)-3-(4-(Bis(4-ethoxyphenyl) amino)phenyl)-2-(4-amino-phenyl)- acrylonitrile cyano-substituted ) based on triphenylamine with D-π-A model. L was further used as a two-photon absorption (2PA, λ = 900, λ = 550 nm δ = 156 GM) live-cell marker for real-time, long-term cell growth and proliferation monitoring, with rapidly adhering whole intracellular membrane-rich system. Remarkably, different from existing organic AIE chromophores and other commercially available probes, L exhibited intense intracellular-AIE property with stable nuclear envelope (NE) staining under two-photon excited microscopy (TPEM) through detailed in cellulo studies. [ABSTRACT FROM AUTHOR]

A novel molybdenum sulfide-chitosan/CdSe quantum dots (MoS-CS/CdSe QDs) composite was prepared by a facile liquid chemistry procedure. The composition and morphology of the composite as-prepared were characterized by a series of measurements. The electrode modified with MoS-CS/CdSe QDs composite has excellent electrochemiluminescence (ECL) property that benefited from the synergistic effect of MoS nanosheets, CdSe QDs, and CS molecules. Based on strong and stable ECL emission, the electrode as-modified was used as ECL sensor for the detection of uric acid (UA) and the results show that the detection linear range for UA is from 0.10 to 140 nM with the detection limit of 0.040 nM. Depending on its good sensitivity and selectivity, this ECL sensor was successfully applied to determine uric acid in urine sample. [ABSTRACT FROM AUTHOR]

Two novel terpyridine-based chromophores with D-A (D = donor, A = acceptor) structural model containing modified triphenylamine moiety ( L and L) have been conveniently synthesized via formylation and reduction in satisfactory yields, and fully characterized. The single crystals of them were obtained and determined by X-ray diffraction analysis. The relationships between structure and photophysical properties of the two chromophores were investigated both experimentally and theoretically. The measured maximum TPA cross-sections per molecular weight ( δ/MW) of the chromophores are 0.63 GM/(g mol) ( L) and 0.72 GM/(g mol) ( L), respectively, in DMF as a high polar solvent. The results indicate that the value of δ/MW could be well tuned by the intramolecular charge transfer (ICT), which could be realized by introducing additional electron-donor/acceptor groups. [ABSTRACT FROM AUTHOR]

By dipping-lifting in sol-gel solution and reducing process, the TiO composite film on the glass plate was first prepared. Then, the PbSe/BaTiO/TiO composite film was fabricated by interface reaction with BaTiO and PbSe on the surface of TiO composite film. The characterization results show that the uniform porous TiO film is made up of the anatase crystal, and the PbSe/BaTiO/TiO composite film is constructed by doping or depositing BaTiO and PbSe nanoparticles on the surface of TiO film. The photoelectrochemical measurement results indicate that the PbSe/BaTiO/TiO composite film has an interesting photoelectrochemical conversion property. [ABSTRACT FROM AUTHOR]

In this study, linear absorption, single-photon excited fluorescence, fluorescence quantum yields, fluorescence lifetime and two-photon excited fluorescence of a series of triphenylamine derivatives ( L1, L2, L3 and L4) have been measured. L1 and L3 are D-π-A type dyes, while L2 and L4 are D-π-D-π-A type dyes (D = donor, A = acceptor). The investigated compounds consist of triphenylamine-bearing donor-substituted and/or systematically extended π-conjugated length, which are designed to gain insight into the effect of the ethoxyl unit and π-linkage length on the linear and nonlinear optical properties. The influence of solvent polarity on the photophysical properties was investigated. Employing time-dependent density functional theory (TD-DFT) calculations, the structure-property relationships are discussed. [ABSTRACT FROM AUTHOR]

A curcumin derivative ligand, 1,7-bis(3-methoxyl-4-acetoxyl)phenyl-1,6-heptadiene-3,5-diketone (diacetylcurcumin, abbreviated as HL), and its Cu and Ni complexes have been synthesized and fully characterized by elemental analyses, IR, HNMR and molar conductivity. The resulting complexes exhibit two-photon excited fluorescence (TPEF) in DMF, and have been proven to be potentially useful for two-photon microscopy imaging in living cells. In addition, cytotoxicity tests showed that the low-micromolar concentrations of ML did not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies. [ABSTRACT FROM AUTHOR]

A novel hydrogen peroxide biosensor based on the BPT/AuNPs/graphene/HRP composite was developed. Firstly, graphene was prepared under the protection of polyvinylpyrrolidone (PVP), and then the AuNPs/graphene composite was synthesized via in situ decoration. Using biphenyldimethanethiol (BPT) as a connector, the AuNPs/graphene composite was immobilized on the surface of the Au electrode, and whereafter the horseradish peroxidase (HRP) was decorated on the surface of the composite by adsorption. The morphology and structure of the products were characterized by XRD, SEM, TEM and UV-visible spectroscopy. The electrocatalytic performance of the resulting BPT/AuNPs/grapheme/HRP composite (namely, biosensor) was studied by electrochemical instrument. The results show that the biosensor has high sensitivity and fast response to HO. In the solution of pH 7.4 with potential −0.2 V, the linear response of the biosensor to HO ranges from 5.0×10 to 2.5×10 M with the detection limit of 1.5×10 M. [ABSTRACT FROM AUTHOR]

Three bis-vinylpyridine compounds (4,4′-bis(2-vinylpyridine)biphenyl L, 4,4′-bis(3-vinylpyridine) biphenyl L, and 4,4′-bis (4-vinylpyridine)biphenyl L) were synthesized by one-step solid-state reactions at room temperature, giving nearly quantitative yields. The compounds obtained were fully characterized by IR, MS and NMR spectroscopies. The structures of L and L were determined by single crystal X-ray diffraction analysis. No noticeable solvatochromism was observed in either one-photon absorption or one-photon excited fluorescence spectra. All of the compounds have high fluorescence quantum yields and long fluorescence lifetime. The linear and nonlinear optical properties of the compounds were investigated both experimentally and theoretically. Interestingly, the position of the nitrogen atom from pyridine influences their two-photon absorption across-sections. [ABSTRACT FROM AUTHOR]

Two new coordination polymers [ZnLI] ( 1) and [CdLI] ( 2) ( L: 3,6-di-(1,2,4-triazole-1-yl)- N-hexylcarbazole) were synthesized and their crystal structures were determined by single-crystal X-ray diffraction techniques. Complexes are both constructed with the helical chains along the 2 screw axis. The coordination bond, C-H...I weak interactions and π-π interactions play significant roles in constructing their 3D or 2D frameworks. Two different DFT calculations are performed for the weak interactions between the helical chains of the three different coordination polymers ([ZnLI], [CdLI] and the reported [HgLI]). The results reveal that weak interactions play important roles in these supramolecular systems of helical configuration, namely, the trend is the shorter H...I distance and π-π stacking distance, the stronger the intermolecular interactions. The photoluminescence of the complexes measured in the solid state at room temperature indicates that the emission intensity varies extensively, which can be rationalized by the heavy atom effect. [ABSTRACT FROM AUTHOR]

Two novel quadrupolar organic compounds, 3-(4-(( E)-2-(9-butyl-9 H-carbazol-6-yl) vinyl)styryl)-9-propyl-9 H-carbazole ( BCSPC) and 3-(3-(3-((1 E)-2-(4-(( E)-2-(3-(3,5-bis(9-butyl-9 H-carbazol-6-yl)phenyl)-9-butyl-9 H-carbazol-6-yl)vinyl)phenyl) vinyl)-9-butyl-9 H-carbazol-6-yl)-5-(9-butyl-9 H-carbazol-6-yl)phenyl)-9-butyl-9 H-carbazole ( BCPBC), with different conjugated arms, have been designed and synthesized. Their one- and two-photon absorption (TPA) and excited fluorescence properties have been experimentally investigated. The two-photon absorption cross-sections of two compounds were estimated by two-photon excited fluorescence technique using 200 fs, 76 MHz, Ti:sapphire laser, which are 22 and 154 GM for BCSPC and BCPBC, respectively. The optimal excitation wavelengths are 780 nm for both BCSPC and BCPBC. A data recording experiment proved the potential application of the materials. [ABSTRACT FROM AUTHOR]

Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work, the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450°C. Then, the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal, and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs, the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light, which have been confirmed by the photoelectrochemical measurements. [ABSTRACT FROM AUTHOR]

Four photopolymerization initiators with D-π-D (D, donor; π, conjugation system) structure have been synthesized by solvent-free reaction and characterized by 1H NMR spectroscopy, IR and elemental analysis. The one-photon and two-photon excited fluorescence have been investigated in different solvents. Experimental results of the one-photon and two-photon absorption cross sections show different trends in OPA and TPA ability with different substitution groups in donor units. [ABSTRACT FROM AUTHOR]

Two carbazole-based polymerization initiators possessing blue fluorescence emission have been synthesized via Wittig reaction in the solid phase at room temperature. Two-photon excited fluorescence (TPEF) spectra for them were investigated under 800 nm fs laser pulse and two-photon absorption cross sections were determined by the Z-scan technique. Then two-photon initiating polymerization (TPIP) microfabrication experiments were successfully carried out. Three-dimensional lattice and artificial defects were gained, indicating that they were viable candidates for the two-photon polymerization initiator in practical application of microfabrication. [ABSTRACT FROM AUTHOR]

Two new metal-centered ferrocene complexes Ni(SCN)2(L)4 (1) and Cu(OAc)2(L)2 (2) (L = 1-[1-ferrocenylmethyl]imidazole) have been synthesized and characterized by elemental analysis, single crystal X-ray diffraction analysis, spectroscopic and cyclic voltammetric measurements. The geometry of Ni(II) in 1 is octahedral, with four ligands in the equatorial plan and two thiocyanate anions at the axial site, while that of Cu(II) in 2 is a distorted octahedron formed by two chealted OAc− and two ligands. Single crystal X-ray diffraction studies reveal that there is partial electron delocalization from ferrocene to imidazole in the two complexes. Electrochemical measurements exhibit that complexes 1 and 2 undergo similar reversible one electron redox processes, suggesting that the ferrocene moieties are equivalent and there are no interactions among them. [ABSTRACT FROM AUTHOR]

Two triphenylamine-based derivatives that can be used as two-photon absorption chromophore, tris{4-[4-(3-trifluoromethyl-3-oxopanoyl)]phenyl}amine (1) and tris{4-[4-(3-phenyl-3-oxopanoyl)] phenyl} amine (2) were successfully synthesized and fully characterized by elemental analysis, IR, 1H NMR and MS. The single crystal X-ray diffraction analysis showed that the molecules possess D-(π-A)3 structures. One-and two-photon absorption and fluorescence in various solvents were experimentally investigated. A data recording experiment proved the potential application of these chromophores. [ABSTRACT FROM AUTHOR]

Molecular packing arrangements play a key role in dominating the photophysical properties of luminophores in aggregated state but fine control of the molecular packing is a great challenge. This article describes a unique cyano substituted styrene pyridinium with interesting solid-state fluorescence that can be finely tuned by simple change of counteranions. The dilute solutions of the organic salts (PyCl, PyNO3, PyOTs and PyPh4B) exhibit very weak fluorescence. The crystals of the organic salts (PyCl, PyNO3, and PyOTs) show much enhanced fluorescence compared with their dilute solutions. It is interesting that the emissions changed from bluish-green to deep-blue and fluorescence quantum yields increase from 2.5% to 13.1% with the increasing of steric hindrance of the anions from chloridion, nitrate, to p-toluenesulfonate. Crystal and DFT studies reveal that the enhanced fluorescence is ascribed to the formation of dimers and bigger anions induce larger molecular separation in dimers. Tetraphenylboron anion with very large steric hindrance impedes the formation of dimers and thus results in non-fluorescent salt (PyPh4B). Meanwhile, this unique dimeric packing endows the crystal of PyNO3 with anisotropic fluorescence. [ABSTRACT FROM AUTHOR]