Dye-sensitized solar cells with solvent-free ionic liquid electrolytes

We systematically studied the temperature-dependent physicochemical properties, such as density, conductivity, and fluidity, of 1,3-dialkylimidazolium iodides. In combination with the amphiphilic Z907Na sensitizer, we have found that it is important to use low-viscosity iodide melts with small cations to achieve high-efficiency dye-sensitized solar cells. By employing high-fluidity eutectic-based melts the device efficiencies considerably increased compared to those for cells with the corresponding state of the art ionic liquid electrolytes.

Properties of poly(sodium 4-styrenesulfonate)-ionic liquid composite film and its application in the determination of trace metals combined with bismuth film electrode

A new kind of bismuth film modified electrode to sensitively detect trace metal ions based on incorporating highly conductive ionic liquids 1-butyl-3-methyl-imidazolium hexafluorophosphate (BMIMPF6) in solid matrices at glassy carbon (GC) was investigated. Poly(sodium 4-styrenesulfonate) (PSS), silica, and Nafion were selected as the solid matrices. The electrochemical properties of the mixed films modified GC were evaluated. The electron transfer rate of Fe(CN)(6)(4-)/Fe(CN)(6)(3-) can be effectively improved at the PSS-BMIMPF6 modified GC.

Dynamic mechanical properties of gel polymer electrolytes containing ionic liquid

The copolymer of acrylonitrile (AN), methyl methacrylate (MMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) is synthesized in 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF(4)). The dynamic mechanical properties of the resulting gel polymer electrolytes containing ionic liquid are measured.

Characterization and electrocatalytic application of a fullerene/ionic-liquid composite

A fullerene/ionic-liquid composite was explored. Transmission Electron Microscopy (TEM) study showed that in the composite, C-60 mainly exists as nano-clusters, Raman spectrum proved that the composite formed only by physical Mix of C-60 and 1-Butyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6), the combination did not change the chemical naturation of C-60. The electrochemical properties of the composite modified electrode, including the electrode reaction control function and the interfacial potential effect were studied.

Nucleation and growth of CUSO4 center dot 5H(2)O crystals on the liquid state stearic acid Langmuir-Blodgett film

Oriented crystallization of CUSO4 center dot 5H(2)O on a Langmuir-Blodgett (LB) film of stearic acid has been studied in the temperature ranges of 73-68 degrees C and 53-20 degrees C, respectively. This is the first time that the LB film at temperature above its melting point has been served as a template to induce nucleation and growth of crystals. The experimental results demonstrated that the LB film in the liquid state has the ability of directing the nucleation and growth of crystals. Moreover, X-ray diffraction patterns of the as prepared crystals revealed that the orientation of the attached crystals on the LB film is affected by temperature greatly.

Size-controlled synthesis of monodispersed gold nanoparticles stabilized by polyelectrolyte-functionalized ionic liquid

The size-controlled synthesis of monodispersed gold nanoparticles (AuNPs) stabilized by polyelectrolyte-functionalized ionic liquid (PFIL) is described. The resulting AuNPs' size, with a narrow distribution, can be tuned by the concentration of HAuCl4. Such PFIL-stabilized AuNPs (PFIL-AuNPs) showed a high stability in water at room temperature for at least one month; they were also quite stable in solutions of pH 7-13 and high concentration of NaCl.

Synthesis and characterisation of novel imidazolium-based ionic liquid crystals with a p-nitroazobenzene moiety

A novel series of compounds with different counter anions, i.e. 1-{[4-(4-nitrophenylazo)phenyloxy]}alkyl-3-methyl-1H-imidazol-3-ium bromide salts (C-n , n=3, 6, 10) and tetrafluoroborate salts (D-n , n=3, 6, 10), were synthesised by the incorporation of an imidazolium group into paraffin side chain-terminated 4-nitroazobenzene derivatives. Their chemical structures were determined by H-1 NMR, C-13 NMR, UV spectroscopy and elemental analysis.

Holmium porphyrin compound liquid crystals: Synthesis and properties

5,10,15,20-Tetra-[(p-alkoxy-m-ethyloxy)phenyl]porphyrin and [5-(p-alkoxy)phenyl-10,15,20-tri-phenyl]porphyrin and their holmium(III) complexes are reported. They display a hexagonal columnar discotic columnar Col(h)) liquid crystal phase and were studied by cyclic voltammetry, surface photovoltage spectroscopy (SPS), electric-field-induced surface photovoltage spectroscopy (EFISPS) and luminescence spectroscopy. Within the accessible potential window, all these compounds exhibit two one-electron reversible redox reactions. Quantum yields of Q band are in the region 0.0045-0.21 at room temperature. The SPS and EFISPS reveal that all the compounds are p-type semiconductors and exhibit photovoltaic response due to pi-pi* electron transitions.

An Engineering-Purpose Preparation Strategy for Ammonium-Type Ionic Liquid with High Purity

A new strategy for preparing ammonium-type ionic liquid (IL) by acid/base neutralization reaction was proposed. The method contributed to preparing hydroxide-based ammonium IL and resulting task specific ionic liquid (TSIL) with high purity using a low-costly and environment-friendly synthetic. route. Halide contamination in the prepared ILs could be markedly decreased than those prepared by well-established anion metathesis method. Moreover, some novel TSILs composed of cations and anions with big steric hindrances could be prepared by this method. Physicochemical properties of the bifunctional TSILs, i.e., density, water content, decomposition temperature, and munal solubility, were also studied in this article.

Facile EG/ionic liquid interfacial synthesis of uniform RE3+ doped NaYF4 nanocubes

Uniform multicolor upconversion luminescent RE3+ doped NaYF4 nanocubes are fabricated through a facile ethylene glycol (EG)/ionic liquid interfacial synthesis route at 80 degrees C, with the ionic liquids acting as both reagents and templates.

Application of a New Cyclic Guanidinium Ionic Liquid on Dye-Sensitized Solar Cells (DSCs)

A new cyclic guanidinium ionic liquid OGI (1,3-dimethyl-2-N ''-methyl-N ''-octylimidazoguanidinium iodide) has been used as a quasi-solid-state electrolyte for dye-sensitized solar cells (DSCs), and 6.38% conversion efficiency was achieved at AM 1.5 simulated sunlight (9.81 mW cm(-2)). Further gelation with SiO2 nanoparticles afforded the solid-state electrolyte, which presented overall conversion efficiency of 5.85%. The diffusion properties of these OGI-based electrolytes were investigated. In the meantime, the optimal structure and ion-pairing interaction in OGI have been proposed by density functional theoretical calculation (DFT) at the B3LYP/6-21G(d,p) level.

The synthesis and properties of meso-tetra(4-alkylamidophenyl)porphyrin liquid crystals and their Zn complexes

A series of novel, long-chain-substituted, porphyrin derivatives, meso-tetra (4-alkylamidophenyl) porphyrin ligands and their Zn complexes (alkyl = 8,10,12,14,16,18) were prepared by acylation of the amino groups of 5,10,15,20-tetra(4-aminophenyl)porphyrin by alkyl chloride. Mesomorphism was investigated by DSC, polarized optical microscopy (POM) and X-ray diffraction (XRD). Only ligands containing chains > 12 carbon atoms displayed liquid crystalline behaviour, which exhibited a high phase transition temperature and a broad mesophase temperature span, Zn complexes showed no liquid crystalline behaviour. Cyclic voltammetry, luminescence spectra and surface photovoltage spectroscopy revealed that covalent linking of an alkylamido group to the tetraphenylporphyrin molecule influences, significantly, the properties of the porphyrin macrocycle.

Enhanced electrochemiluminescence sensor from tris(2,2 '-bipyridyl) ruthenium(II) incorporated into MCM-41 and an ionic liquid-based carbon paste electrode

The electrochemiluminescence (ECL) of tris(2,29-bipyridyl) ruthenium(II) [Ru(bpy)(3)(2+)] ion-exchanged in the sulfonic-functionalized MCM-41 silicas was developed with tripropylamine (TPrA) as a co-reactant in a carbon paste electrode (CPE) using a room temperature ionic liquid (IL) as a binder. The sulfonic-functionalized silicas MCM-41 were used for preparing an ECL sensor by the electrostatic interactions between Ru( bpy)(3)(2+) cations and sulfonic acid groups. We used the IL as a binder to construct the CPE (IL-CPE) to replace the traditional binder of the CPE (T-CPE)-silicone oil. The results indicated that the MCM-41-modified IL-CPE had more open structures to allow faster diffusion of Ru( bpy)(3)(2+) and that the ionic liquid also acted as a conducting bridge to connect TPrA with Ru( bpy)(3)(2+) sites immobilized in the electrode, resulting in a higher ECL intensity compared with the MCM-41-modified T-CPE. Herein, the detection limit for TPrA of the MCM-41-modified IL-CPE was 7.2 nM, which was two orders of magnitude lower than that observed at the T-CPE. When this new sensor was used in flow injection analysis (FIA), the MCM-41-modified IL-CPE ECL sensor also showed good reproducibility. Furthermore, the sensor could also be renewed easily by mechanical polishing whenever needed.

Rhythmic growth of ring-banded spherulites in blends of liquid crystalline methoxy-poly(aryl ether ketone) and poly(aryl ether ether ketone)

Rhythmic growth of ring-banded spherulites in blends of liquid crystalline methoxy-poly(aryl ether ketone) (M-PAEK) and poly(aryl ether ether ketone) (PEEK) has been investigated by means of differential scanning calorimetry (DSC), polarized light microscopy (PLM), and scanning electron microscopy (SEM) techniques. The measurements reveal that the formation of the rhythmically grown ring-banded spherulites in the M-PAEK/PEEK blends is strongly dependent on the blend composition. In the M.-PAEK-rich blends, upon cooling, an unusual ring-banded spherulite is formed, which is ascribed to structural discontinuity caused by a rhythmic radial growth. For the 50:50 M-PAEK/PEEK blend, ring-banded spherulites and individual PEEK spherulites coexist in the system. In the blends with PEEK as the predominant component, M-PAEK is rejected into the boundary of PEEK spherulites. The cooling rate and crystallization temperature have great effect on the phase behavior, especially the ring-banded spherulite formation in the blends. In addition, the effects of M-PAEK phase transition rate and phase separation rate on banded spherulite formation is discussed.

Electrochemical catalysis and thermal stability characterization of laccase-carbon nanotubes-ionic liquid nanocomposite modified graphite electrode

The hydrophobic carbon nanotubes-ionic liquid (CNTs-IL) get forms a stable modified film on hydrophobic graphite electrode surface. Laccase immobilized on the CNTs-IL gel film modified electrode shows good thermal stability and enhanced electrochemical catalytic ability. The optimal bioactivity occurs with increasing temperature and this optimum is 20 degrees C higher in comparison to free laccase. The improvement of laccase thermal stability may be due to the microenvironment of hydrophobic CNTs-IL gel on graphite electrode surface. On the other hand, the sensitive detection of oxygen has been achieved due to the feasibility of oxygen reduction by both of laccase and nanocomposite of CNTs-IL gel. Furthermore, the laccase hybrid nanocomposite also shows the fast electrochemical response and high sensitivity to the inhibitors of halide ions with the approximate IC50 of 0.01, 4.2 and 87.5 mM for the fluoride, chloride and bromide ions, respectively. It implies the feasibility of laccase modified electrode as an inhibition biosensor to detect the modulators of laccase.