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The mechanism of photocatalytic biomass reforming for H2 production is far from fully understood. This study uses functionalized graphene dots with Pt-cocatalyst to reform cellulose in an alkaline ...

High stability and uniform Li deposition are essential for realizing applications of Li-metal batteries (LMBs). Therefore, a scaffold for polymer electrolytes is designed to achieve highly stable operation and dendrite-free Li deposition. A porous membrane of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) is synthesized as a scaffold to host a networked poly(ethylene oxide) (PEO)-based solid polymer electrolyte (NSPE) and form a scaffold-hosted electrolyte (NSPE@PF) that exhibits a considerably higher ionic conductivity and Li+-transference number at 30 °C than the reported PEO-based solid polymer electrolytes do. The PVdF-HFP scaffold renders the NSPE@PF electrochemically stable until 5.4 V (vs. Li/Li+). The PVdF-HFP membrane facilitates uniform Li deposition on both Cu- and Li-metal anodes with negligible dendrite growth in both solid-polymer and liquid electrolyte systems. LMBs containing the NSPE@PF exhibit high capacities and a high cycling stability of up to 1100 cycles. The high-dielectric feature of the PVdF-HFP scaffold facilitates counter-ion-pair dissociation and extends the stable voltage range. Its anion-tethering ability minimizes the space-charge zones on the Li-anode surface and suppresses Li-dendrite growth. Moreover, the high mechanical strength of the scaffold facilitates the synthesis of thin and practically usable NSPE@PFs. This scaffold design is promising for realizing LMB applications.

Highly efficient nanocomposite electrolytes were prepared by mixing the montmorillonite (MMT) clay nanofillers and iodide poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) gel electrolytes for the purpose of measuring the performance of quasi-solid-state dye-sensitized solar cells (QS-DSSCs). The impacts of different amounts of MMT nanofillers on the ion diffusivity, conductivity of the polymer gel electrolytes (PGEs), and the photovoltaic performance of the cells using the PGEs were evaluated. The results indicated that the use of 5 wt.% MMT markedly increase the ion diffusivity and conductivity of the PVDF-HFP PGE. The introduction of 5 wt.% nanofillers considerably reduced the Warburg diffusion resistance, which made to the high performance of the QS-DSSCs. Cells utilizing 5 wt.% MMT nanofillers were shown to obtain a power conversion efficiency (PCE) (6.77%) higher than that obtained for cells using pure PGEs and identical to that obtained using liquid electrolytes (LEs) (6.77%). The high PCE was a result of an enhance in the current density in the presence of the 5 wt.% MMT nanofillers. The DSSC efficiency was found to maintain 99.9% of its initial value after 194 h of testing at 60℃ under dark environments. The stability of the DSSC using PGEs with the optimal amount of MMT nanofillers was higher than that for the cells using liquid electrolyte and pure PGE.

Electrochemical water splitting using renewable energy shows promise for the development of sustainable hydrogen production methods. The process requires a highly active electrocatalyst for oxygen evolution to improve the overall water splitting efficiency. The present study showed that oxygen evolution improved dramatically upon the addition of glycine to cobalt phosphate, when the glycine was added to the electrolyte solution during electrodeposition. The functionality of the organic molecules was investigated using in situ UV-vis absorption, in situ X-ray absorption fine structure, and in situ infrared (IR) absorption spectroscopy in the attenuated total reflection mode. The results demonstrated that the glycine molecules assembled cobalt oxide clusters composed of CoO6 (CoOOH) octahedrons a few nanometers in diameter upon the electrodeposition of cobalt catalysts. This suggests that the cobalt-glycine catalyst can decompose water to oxygen gas efficiently, because the number of cobalt oxide clusters increased as active reaction sites upon the addition of glycine molecules.

High-efficiency, stable bifacial dye-sensitized solar cells (DSSCs) are prepared for application under indoor light conditions. A 3-methoxypropionitrile solvent and cobalt redox couples are utilized to prepare the electrolytes. To obtain the best cell performance, the components of the DSSCs, including electrolytes, photoanodes, and counter electrodes (CEs), are regulated. The experimental results indicate that an electrolyte comprising a Co (II/III) ratio of 0.11/0.025 M, 1.2 M 4-tert-butylpyridine, Y123 dye, a CE with the platinum (Pt) layer thickness of 0.16 nm, and a photoanode with titanium dioxide (TiO2) layer thickness of 10 μm (6 μm main layer and 4 μm scattering layer) are the best conditions under which to achieve a high power conversion efficiency. It is also found that the best cells have high recombination resistance at the photoelectrode/electrolyte interface and low charge transfer resistance at the counter electrode/electrolyte interface, which contributes to, respectively, the high current density and open-circuit voltage of the corresponding cells. This DSSC can achieve efficiencies of 22.66%, 23.48%, and 24.52%, respectively, under T5 light illumination of 201.8, 607.8, and 999.6 lx. For fabrication of bifacial DSSCs with a semitransparent property, photoanodes without the TiO2 scattering layer, as well as an ultrathin Pt film, are utilized. The thicknesses of the TiO2 main layer and Pt film are reregulated. This shows that a Pt film with 0.55 nm thickness has both high transmittance (76.01%) and catalytic activity. By using an 8 μm TiO2 main layer, optimal cell efficiencies of 20.65% and 17.31% can be achieved, respectively, for the front-side and back-side illuminations of 200 lx T5 light. The cells are highly stable during a long-term performance test at both 35 and 50 °C.

High-efficiency and stable quasi-solid-state dye-sensitized solar cells (QS-DSSCs) are fabricated using printable polymer gel electrolytes for application under room light conditions. The printable electrolytes are prepared based on 3-methoxypropionitrile liquid electrolytes containing iodide/triiodide redox mediator, polyethylene oxide/polyvinylidene fluoride gelator, and titanium dioxide nanofillers. To obtain the optimal performance of the DSSCs, the composition of the printable electrolytes and the thickness of the photoelectrode are regulated. The results show that the polymers composition has little effect on the conversion efficiency of the QS-DSSCs under ambient-light conditions. However, the iodine concentration and the thickness of the titanium dioxide film are important parameters. The experimental results indicate that the printable electrolyte containing 0.01 M iodine, and a titanium dioxide photoelectrode with the thickness of 4 µm main layer and 4 µm scattering layer are the optimal condition to obtain high cell efficiencies. It also shows that the best QS-DSSCs have high recombination resistance and high incident photon to current efficiency values, which contribute, respectively, to the high open circuit voltage and the current density of the corresponding cells. Therefore, the cells can achieve efficiencies of 15.39% and 20.63% under 200 and 600 lx illuminance, respectively. These efficiencies are almost similar to the conversion efficiencies of the corresponding liquid-state DSSC. By applying this printable electrolyte to a sub-module cell, an energy conversion efficiency of 12.23% is achieved under 200 lx illuminance. The study of long-term stability shows that the efficiency of the QS-DSSC can retain 97% of its initial performance after 1000 h testing under 200 lx illuminance, exhibiting high stability of the cells.

Highly efficient quasi-solid-state dye-sensitized solar cells (QS-DSSCs) are fabricated using nanocomposite gel electrolytes and applied under room light conditions (200 lx). To obtain high energy conversion efficiency in QS-DSSCs, the important components of the DSSC are systematically optimized based on their performance in liquid-state DSSCs. It shows that the liquid cell using the 3-methoxypropionitrile-based cobalt electrolyte has higher efficiency (18.91%) than the cell using the acetonitrile-based electrolyte (17.82%) under 200 lx illumination due to the higher charge recombination resistance at the photoelectrode/electrolyte interface for the 3-methoxypropionitrile system. Poly(vinylidene fluoride-co-hexafluoropropylene) is utilized as the gelator of the liquid electrolytes to prepare polymer gel electrolytes. Furthermore, to improve the performance of the QS-DSSCs, different metal oxide nanoparticles are introduced as nanofillers of the polymer gel electrolytes. It shows that the zinc oxide nanof...

Solid-oxide electrolytes (SEs) are an alternative to using conventional organic liquid electrolytes for lithium ion batteries (LIBs) and offer solutions to the challenges associated with safety and energy density. However, SE-based LIBs suffer from high interfacial resistance between the electrolyte and electrodes. In this study, we develop a gelled poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) framework to facilitate Li+ transfer across the interface between an SE pellet of garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZTO) and a LiFePO4 cathode. The gelled polymeric framework exhibits high ionic conductivity and a large Li+ transference number (tLi+) of 0.67 that results from the synergy between the nitrile and acrylate functionalities and minimizes the formation of ion–solvent clusters and mobility of PF6− anions. The large tLi+ characteristic is advantageous for forming a junction with SEs featuring a unity tLi+ and suppressing polarization caused by PF6− accumulation. When coupled with the LLZTO pellet, the gel polymer electrolyte may exhibit collimated Li+ transport that suppresses Li-dendrite formation. The resulting Li|LLZTO|LiFePO4 battery demonstrates outstanding capacity (e.g., 154 mA h g−1 at 0.1 mA cm−2 and 25 °C), high rate retention, and excellent cycling stability. The present study demonstrates that the gelled P(AN-co-MA) framework acts an ideal interface between the SE and cathode for fabricating quasi-solid LIBs.

Major challenges in the development of lithium metal batteries (LMBs) are nonuniform Li deposition and substantial variation in Li volume, resulting in Li dendrite growth and Li consumption. A networked solid-state polymer electrolyte (NSPE) that comprises poly(ethylene oxide-co-propylene oxide) (P(EO-co-PO)) and poly(dimethylsiloxane) diglycidyl ether (PDMSDGE) chains and a lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is developed for resolving the Li deposition challenges. The methyl pendants on P(EO-co-PO) and PDMSDGE chains render the NSPE a low-surface-energy film for complete coverages on the high-energy Li electrode and regulating Li+ transport. The low-surface-energy characteristics induces overspreading of the highly lithiophilic C-F ends of the TFSI− anion at the Li electrode–NSPE interface, forming Li−F bonds and facilitating uniform Li deposition. The elastic PDMS chains enable the NSPE to accommodate Li volume changes. Liquid-phase Li||LiFePO4 and Cu||LiFePO4 cells with the NSPE as an artificial interface or a solid-state Li||LiFePO4 cell with the NSPE as solid electrolyte had uniform anodic Li deposition, resulting in long cycle life and high coulombic efficiency. Our study demonstrated that (a) low surface energy to completely cover the Li anode and (b) the presence of interfacial Li − F bonds are two essential requirements for uniform Li deposition in LMBs.

A graphene oxide sponge (GOS) is utilized for the first time as a nanofiller (NF) in printable electrolytes (PEs) based on poly(ethylene oxide) and poly(vinylidene fluoride) for quasi-solid-state dye-sensitized solar cells (QS-DSSCs). The effects of the various concentrations of GOS NFs on the ion diffusivity and conductivity of electrolytes and the performance of the QS-DSSCs are studied. The results show that the presence of GOS NFs significantly increases the diffusivity and conductivity of the PEs. The introduction of 1.5 wt % of GOS NFs decreases the charge-transfer resistance at the Pt-counter electrode/electrolyte interface (Rpt) and increases the recombination resistance at the photoelectrode/electrolyte interface (Rct). QS-DSSC utilizing 1.5 wt % GOS NFs can achieve an energy conversion efficiency (8.78%) higher than that found for their liquid counterpart and other reported polymer gel electrolytes/GO NFs based DSSCs. The high energy conversion efficiency is a consequence of the increase in both...

All-solid-state polymer electrolytes (SPEs) are key for improving lithium-ion battery (LIB) safety and the practical application of metallic Li anodes. The major challenges of developing SPEs are their ionic conductivity, interfacial affinity, and flammability. In this article, synthesis of an SPE comprising lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and poly(ethylene oxide) networked with an acylamino-functionalized crosslinker is reported. The acylamino sites, urethane and biuret linkages, dissociate LiTFSI and may form deep-eutectic-solvent domains to facilitate ion transport. This SPE is fire-retarding because CO2 evolves when the urethane decomposes at high temperatures. When operated at room temperature, the all-solid-state Li|SPE|LiFePO4 cell exhibits a high rate capability and long lifespan. Due to the high elasticity of the SPE, the polymers can self-rearrange during operation to reduce the Li–SPE interfacial resistance and regulate Li+-ion transport for uniform Li deposition. The rearrangement may involve migration of the low-energy alkane chains in the crosslinker toward the Li-anode, resulting in overspreading of lithiophilic carbonyl groups and F-atoms of TFSI− at the interface. This rearrangement property enables the SPE to act as an artificial interlayer in liquid-electrolyte LIBs. The advantages of using an acylamino-functionalized crosslinker to synthesize a networked SPE for high ionic conductivity and interfacial compatibility are demonstrated.

In this study, highly efficient printable electrolytes (PEs) were prepared for a quasi-solid-state dye-sensitized solar cell (QS-DSSC). A liquid electrolyte based on iodide/triiodide redox couples and 3-methoxypropionitrile (MPN) was utilized to prepare the PEs. Poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) were employed as solidifying agents to optimize the properties of the PEs. Moreover, TiO2 nanofillers (NFs) were added to the PEs to enhance the performance of the DSSCs. The results indicate that a PE based on a PEO/PMMA ratio of 7/3 was optimal for efficient printing. The energy conversion efficiency of the DSSC achieved by using this PE was 8.48%, which was higher than the efficiencies of the cell using only PEO PE (7.63%) and liquid-cells (8.32%). This was mainly due to the increase in the electrolyte conductivity and charge transfer resistance at the photoelectrode/electrolyte interface of the DSSC. The presence of 10 wt% TiO2 NFs in the PEs increased the efficiency of the QS-DSSC to 9.12%. The sub-module cell fabricated by using the PE with TiO2 NFs achieved an efficiency of 6.78%. The PE based DSSC exhibited stable long-term efficiency during thermal aging at 60 °C.

Low-cost counter electrodes for dye-sensitized solar cells (DSSCs) are prepared using platinum/carbon black (Pt/CB) composites via a spin-coating process. Ethyl cellulose (EC) is used as a binder to regulate the viscosity of the Pt/CB composites to facilitate the spin-coating process. The ratio of Pt to CB is ca. 1:3. The effects of film composition (Pt/CB:EC = 30:15, 30:4) and number of coating layers on the electrochemical properties of the Pt/CB electrodes and the performance of the corresponding DSSCs are studied. The results show that Pt/CB films with the lower concentration of EC (Pt/CB:EC = 30:4) exhibit high electrochemical activity, low charge transfer resistance, and good DSSC performance. These results are attributed to the lower loading of EC, which facilitates the charge transfer of the electrodes. DSSCs using these Pt/CB composite counter electrodes with lower loading of EC achieve a high conversion efficiency (8.06%) comparable to that of cells using Pt.

Introduction: When dietary carbohydrate replaces fat, HDL cholesterol (HDL-C) and the primary HDL protein apolipoprotein A1 (apoA1) decrease. The proportion in plasma of large HDL2 decreases while small HDL3 increases. These findings suggest that diet affects metabolically important attributes of HDL that produce the size changes. We studied in humans the effect of dietary carbohydrate and unsaturated fat on the HDL proteome and metabolism of 9 HDL proteins across 5 HDL sizes. Methods and Results: Twelve participants were placed on a healthy, controlled diet high in unsaturated fat (HF) or high in carbohydrate (HC) in a randomized crossover design. At the end of each 4-week diet period, subjects were infused with a stable isotope tracer (D3-Leu) in order to label all newly synthesized HDL proteins. Blood samples were collected and tracer was followed for 70 hrs post-infusion. ApoA1-HDL was isolated by immunoaffinity purification, separated into 5 HDL particle sizes, and prepared for analysis by mass spectrometry. We used label free quantification to characterize the HDL proteome. The proteome composition and distribution across the 5 HDL sizes were remarkably conserved in all subjects on both diets. Diet altered the abundance of several proteins on the major HDL sizes alpha2 and alpha3. The HC diet increased proteins involved in lipid metabolism (apoC3, apoA2) and decreased antioxidant (PON1, PON3) and protease inhibitor (SERPINA3, SERPING1) proteins. We also monitored the metabolism of 9 proteins that likely affect HDL metabolism - apoA1, apoA2, apoA4, apoC3, apoE, apoJ, apoL1, apoM and LCAT. We used parallel reaction monitoring and XPI software to measure the amount of D3-Leu tracer over time in these 9 proteins across the 5 HDL sizes. We found that the HC diet increased apoA2 and apoJ and decreased apoA1 pool sizes on large HDL. The HC diet also increased apoM turnover in large HDL, and apoA1, apoA2, and apoE turnover across the HDL size range. Conclusions: Dietary carbohydrate when it replaces unsaturated fat alters the HDL proteome and metabolism of several HDL proteins on specific HDL sizes. Carbohydrate increases the abundance of proteins involved in lipid metabolism, decreases antioxidant and protease inhibitor proteins, and accelerates turnover of apoA1, apoA2, apoE, and apoM. This study suggests that diet modulates HDL function by affecting HDL composition and the metabolism of major HDL proteins.

High-performance quasi-solid-state electrolytes with printable characteristics are developed herein for dye-sensitized solar cells (DSSCs). The printable electrolytes are prepared based on a 3-methoxypropionitrile liquid electrolyte containing I−/I3− redox couples. Poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF) are utilized as agents to regulate the viscosity and properties of the electrolyte pastes; furthermore, TiO2 nanoparticles are used as a filler to enhance the performance of the electrolytes. The results show that PEO is a required material to prepare the electrolyte pastes for operation by a printing process. However, if only PEO is utilized, the conversion efficiency of the corresponding cell (7.65%) is much lower than that of the liquid one (8.34%). By introducing PVDF as a co-regulating agent, the resultant cell can achieve an efficiency of 8.32% similar to that of the liquid cell, mainly attributed to the decrease of charge transfer resistance at the electrolyte/Pt counter electrode interface. In addition, if 4 wt% TiO2 nanoparticles are introduced as fillers into the printable electrolyte, the cell efficiency can be further increased to 8.91%. By applying this printable electrolyte to a sub-module cell, a conversion efficiency of 6.45% is achieved. The DSSCs prepared by the printing process are stable under a long-term stability test at 60 °C.

A facile and cost-effective method is proposed herein to fabricate highly electrocatalytic carbon black/copper sulfide (CB/CuXS) composite counter electrodes for quantum-dot-sensitized solar cells (QDSSCs). In brief, mesoporous CB thin films and copper salts are first deposited on FTO substrates by a spin-coating process; a sulfidation treatment is then conducted to facilitate accumulations of CuXS catalysts in the mesoporous structure. Experimental results illustrate that during the sulfidation, an ion exchange reaction and a reduction of Cu(II) to Cu(I) take place simultaneously, and that the obtained CuXS catalyst possesses a nonstoichiometric phase. The electrochemical properties of the resultant composite films are carefully investigated. The results show that the electrocatalytic activity of the CB/CuXS films related to the polysulfide redox reaction is much superior to that of common platinum. Compared to a solar cell equipped with a solution-processed CuS counter electrode, the QDSSC using a composite film prepared only by a single spin-coating displays similar photovoltaic performance. Furthermore, increasing the coating times can lead to improvements both in the electrocatalytic activity of the CB/CuXS films and in the cell performance of the relevant QDSSCs. When CdS/CdSe sensitizers are employed, the QDSSC using a CB/CuXS counter electrode fabricated with three coating times demonstrates a conversion efficiency of 5.62% under 1 sun irradiation.

Propionitrile (PPN) solvent based iodide/triiodide liquid-electrolyte is utilized to prepare highly efficient poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) polymer gel electrolytes (PGEs) of dye-sensitized solar cells, aiming at improving the energy conversion efficiency as well as the stability of gel-state DSSCs. The concentrations effect of the PVdF-HFP on the properties of PGEs and the performance of the corresponding cells are studied. The results show that the in-situ gelation is performed for the PVdF-HFP concentration range of 8–18% at room temperature. However, increasing the concentration of polymer in the PGEs triggers a decrease in the diffusivity and conductivity of the PGEs, but an increase in the phase transition temperature of the PGEs. A high phase transition temperature is obtained for the PGEs with 18 wt% PVdF-HFP, which increase the long-term stability of the gel-state DSSC. By using the 18 wt% PVdF-HFP in the presence of 5 wt% TiO2 nanofillers (NFs), gel-state cells with an efficiency of 8.38% can be obtained, which is higher than that achieved by liquid-state cells (7.55%). After 1000 h test at room temperature (RT) and 50 °C, the cell can retain 96% and 82%, respectively, of its initial efficiency.

Polymer gel electrolytes (PGEs) of cobalt redox system are prepared for dye sensitized solar cell (DSSC) applications. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is used as a gelator of an acetonitrile (ACN) liquid electrolyte containing tris(2,2'-bipyridine)cobalt(II/III) redox couple. Titanium dioxide (TiO2) and titanium carbide (TiC) nanoparticles are utilized as nanofillers (NFs) of this PGE, and the effects of the two NFs on the conductivity of the PGEs, charge-transfer resistances at the electrode/PGE interface, and the performance of the gel-state DSSCs are studied and compared. The results show that the presence of TiC NFs significantly increases the conductivity of the PGE and decreases the charge-transfer resistance at the Pt counter-electrode (CE)/PGE interface. Therefore, the gel-state DSSC utilizing TiC NFs can achieve a conversion efficiency (6.29%) comparable to its liquid counterpart (6.30%), and, furthermore, the cell efficiency can retain 94% of its initial value after a 1000 h stability test at 50 °C. On the contrary, introduction of TiO2 NFs in the PGE causes a decrease of cell performances. It shows that the presence of TiO2 NFs increases the charge-transfer resistance at the Pt CE/PGE interface, induces the charge recombination at the photoanode/PGE interface, and, furthermore, causes a dye desorption in a long-term-stability test. These results are different from those reported for the iodide redox system and are ascribed to a specific attractive interaction between TiO2 and cobalt redox ions.

Sodium acetate (NaAc) is utilized as an additive in cationic precursors of the successive ionic layer adsorption and reaction (SILAR) process to fabricate CdS quantum-dot (QD)-sensitized photoelectrodes. The effects of the NaAc concentration on the deposition rate and distribution of QDs in mesoporous TiO 2 films, as well as on the performance of CdS-sensitized solar cells are studied. The experimental results show that the presence of NaAc can significantly accelerate the deposition of CdS, improve the QD distribution across photoelectrodes, and thereby, increase the performance of solar cells. These results are mainly attributed to the pH-elevation effect of NaAc to the cationic precursors which increases the electrostatic interaction of the TiO 2 film to cadmium ions. The light-to-energy conversion efficiency of the CdS-sensitized solar cell increases with increasing concentration of the NaAc and approaches a maximum value (3.11%) at 0.05 M NaAc. Additionally, an ionic exchange is carried out on the photoelectrode to transform the deposited CdS into CdS 1−x Se x ternary QDs. The light-absorption range of the photoelectrode is extended and an exceptional power conversion efficiency of 4.51% is achieved due to this treatment.

This study proposes incorporating nitrogen-doped graphene oxide dots (NGODs) with graphene oxide (GO) sheets to form a stable and effective NGOD:GO composite for photocatalytic H 2 production through water splitting under visible light illumination. Although Pt-deposited NGOD catalysts were active in the photocatalytic H 2 production reaction, they were only moderately stable. Introducing GO sheets in light-absorbing NGODs effectively mediated the transfer of photogenerated electrons from the NGODs to the GO sheets. This vectorial electron transfer, confirmed by a photoluminescence spectroscopy analysis, led to the relocation of the reaction sites from the NGODs to the GO sheets, protecting the NGODs from attack by reaction intermediates. Moreover, the GO sheets acted as an electron sink, facilitating charge separation in the NGODs. When 3 wt% Pt was deposited on the developed NGOD:GO catalyst, the catalyst steadily catalyzed H 2 production from a 10 vol% aqueous solution of triethanolamine under visible light illumination for 96 h, unlike a NGOD catalyst that exhibited an activity decay of 50% within 96 h. The apparent quantum yield of H 2 under 420-nm light irradiation was 16.0%, demonstrating the high activity of the NGOD:GO catalyst.

Cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM) are used to study the electrodeposition of copper on an ordered Au(111) electrode modified with mercaptoacetic acid (MAA) in 0.1 M H 2 SO 4 + 0.1 mM CuSO 4 . A CV experiment with potential ramping at 5 mV/s from 0.4 to 0 V (vs. Ag/AgCl) results in a monolayer of Cu on this electrode, demonstrating a minor effect of MAA on Cu deposition, an atypical behavior for a thiol modifier on gold electrode. The MAA-modified Au(111) is imaged by STM, which reveals ordered structures on atomically smooth terraces punctured by steps and pits one atom deep. Cu deposition starts at these defective sites and grows to the entire electrode. The MAA modifier prompts uniform Cu deposition, leading to a smooth Cu film on Au(111). On top of the Cu film there is a major striped phase due to MAA molecules and a minor Moire pattern due to bisulfate anions. These ordered surface structures suggest a crystalline Cu substrate, possibly a face-centered cubic (fcc) structure with its (111) plane lying parallel to the Au(111) substrate. Triangular Cu blocks with their apexes pointing in opposite directions are observed, which implies twinned fcc Cu crystallites. Anodic stripping of the Cu deposit restores the MAA adlayer with a notable amount of defects in the film, which implies a simultaneous loss of MAA and Cu.

This paper reports a gel polymer electrolyte (GPE) that is synthesized as a liquid solution and transforms into a gel on-site after injection into lithium-ion batteries (LIBs). The GPE is produced by mixing poly (acrylonitrile-co-methacrylate) (P(AN-co-MA)) and polyethylene glycol (PEG) with a conventional carbonate-solvated LiPF6 liquid electrolyte (LE). P(AN-co-MA) dissociates counter-ion pairs and PEG promotes polymer-crosslinking for electrolyte gelation. The GPE has a high dielectric constant and low dielectric loss because of ion-pair dissociation and facilitated ion motion. When incorporated with a separator, the GPE exhibits an ionic conductivity of 1.7 × 10−3 S cm−1 and a Li transference number (tLi+) of 0.62. The corresponding values for the LE are 9.1 × 10−4 S cm−1 and 0.37, respectively. The high dielectric permittivity and tLi+ render the GPE stable at 5.2 V (vs. Li/Li+). The GPE outperforms the LE when assembled into Li||LiFePO4 batteries, exhibiting superior capacity, high rate retention, and cycling stability. Moreover, the GPE has low flammability such that a graphite|GPE|LiFePO4 pouch-cell battery operates smoothly under folding or after truncation. The on-site coagulation design ensures that the developed GPE can be used in existing LIB assembly lines to produce high-quality LIBs that can be applied in diverse power devices.

High-performance printable electrolytes (PEs) containing Co+2/Co+3 or I−/I3− redox-couple are prepared to fabricate quasi-solid-state (QS) dye-sensitized solar cells (QS-DSSCs) for room light environment applications. Polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are utilized to prepare PEs. Various parameters are regulated to obtain the optimal power conversion efficiencies (PCEs). For the I−/I3− system, the QS-DSSCs using PEO and PEO/PMMA PEs achieve nearly identical PCEs (16.32% and 16.40%, respectively) under the optimal conditions. However, the PCEs obtained for the Co+2/Co+3 system are markedly higher and the cell using PEO PE has a higher PCE (21.06%) than that using PEO/PMMA (18.14%). This difference is ascribed to the different composition of Li+ and Co+3 around the photoelectrode. The presence of Li+ around the interface will repel Co+3 away from the interface, decreasing the recombination of excited electrons to Co+3. According to the molecular structure, PMMA has more lone pair electrons to coordinate with Li+ ions, which will decrease the concentration of free Li+ more significantly than does by PEO. Therefore, the presence of PMMA will decrease and increase, respectively, the Li+ and Co+3 concentrations at the photoelectrode/electrolyte interface, resulting in more significant recombination of electrons to the Co+3. Consequently, the PCE of the PEO/PMMA cell is lower than that of the PEO cell. This effect doesn’t occur in I−/I3− system because the concentration variation of negatively charged ions did not affect significantly the electrons recombination at the interfacial. By using this cobalt PE, a bifacial QS-DSSC can achieve PCEs of 17.22% and 14.25%, respectively, under front-side and back-side illumination by 200 lx T5 light. A sub-module QS-DSSC using the cobalt PE can attain a PCE of 12.56%.

Introduction: When dietary carbohydrate replaces fat, HDL-C and apoA1 decrease. The proportion in plasma of large HDL2 decreases while small HDL3 increases. These findings suggest that diet affects metabolically important attributes of HDL that produce the size changes. We studied in humans the effect of dietary carbohydrate and unsaturated fat on the HDL proteome and metabolism of 9 HDL proteins across 6 HDL sizes. Methods and Results: Twelve participants were placed on a controlled high unsaturated fat (HF) or high carbohydrate (HC) diet in a randomized crossover design. At the end of each 4-week diet period, subjects were infused with D3-Leu tracer, and blood was collected for 70 hrs. ApoA1-HDL was prepared by immunoaffinity purification, separated into 6 sizes α0, α1, α2, α3, preβ, and Conclusions: Dietary carbohydrate when it replaces unsaturated fat alters the HDL proteome and metabolism of several HDL proteins on specific HDL sizes. Carbohydrate increases the abundance of proteins involved in lipid metabolism and the acute phase response, decreases antioxidant and protease inhibitor proteins, and enhances turnover of apoE and apoA1. This study suggests that diet modulates HDL function by affecting HDL composition and the metabolism of major HDL proteins.

In this study, without the use of any organic solvents, the performance of an ionic liquid (IL) electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMIm-TFSI), is improved by linking some of the EMIm+ cations with an ether bridge (–O(CH2)2O–) to form C6O2(MIm)22+ dications in the IL. After replacing 5% of cations with dications, the resultant IL (EM-di5) exhibits a lowered freezing temperature and an amorphous ion arrangement. Spectroscopic analyses clarify that introducing dications reduces the interionic interaction in the IL. When carbon-based electric double-layer capacitors (EDLCs) are assembled using the ILs, the EM-di5 EDLC exhibits lower ion transport resistance and a wider operation temperature range (60 to −20 °C) than does the EMIm-TFSI EDLC (60 to 0 °C). The EM-di5 EDLC presents high electrode capacitances of 200 and 160 F g−1 over a 3.5 V window at 25 and −20 °C, respectively, because the presence of dications facilitates ion penetration into the micropores. The EM-di5 EDLC delivers a specific energy of 70 W h kg−1 at a specific power of 1.3 kW kg−1 (on total carbon mass) at −20 °C. This study presents a molecular-architecture strategy to extend the applicability of ILs in EDLCs to low-temperature environments with improved capacitance.

Printable electrolytes for dye-sensitized solar cells (DSSCs) are prepared using a low volatile solvent, gamma-butyrolactone (gBL). Various polymers including polyvinyl acetate (PVA), polyacrylonotrile (PAN), and poly(acrylonitrile-co-vinylacetate) (PAN-VA) are used to regulate the viscosity of the electrolytes. The results show that PAN is the best polymer interms of viscosity, conductivity, and performance of the DSSCs. Increasing the concentration of PAN increases the viscosity of the electrolyte paste, which is advantageous to the operation of a printing process but decreases the electrolyte conductivity and cell performance. This drawback can be compensated by introducing of TiO2 or TiC nanofillers. The quasi-solid-state DSSC prepared using a printing process achieves a conversion efficiency (7.85%) similar to that of the corresponding liquid cell (7.87%). The stability test shows that the presence of TiO2 nanofillers triggers a gradual desorption of dye, decreasing DSSC performance. However, this problem does not appear for the electrolyte using TiC nanofillers, with cell efficiency retaining 96% of its initial value after a 500 h test.

Propionitrile (PPN) or 3-methoxypropionitrile (MPN) is mixed with acetonitrile (ACN) to prepare ACN/PPN and ACN/MPN co-solvents and used to fabricate polymer gel electrolytes (PGEs) of dye-sensitized solar cells (DSSCs), aiming at improving the stability of gel-state DSSCs. Co-solvents with various ratios are utilized to prepare PGEs using poly(acrylonitrile-co-vinyl acetate) (PAN-VA) as the gelator. The ratio effects of the co-solvents on the properties of PGEs and the performances of the corresponding DSSCs are studied. The results show that in-situ gelation of the gel-electrolytes can still be performed at the presence of 40% PPN or 30% MPN. However, increasing the composition of PPN and MPN in the co-solvents triggers a decrease in the diffusivity and conductivity of the PGEs, but an increase in the viscosity. Therefore, the energy conversion efficiencies of the cells decrease as a result. However, the introduction of PPN and MPN elevates the gel-to-liquid transition temperature (Tp) of the PGEs which significantly increases the stability of the gel-state DSSCs. Comparing between the effects of the two co-solvents, PPN and MPN have similar effect on elevation of Tp, but the conductivity of PGEs and the corresponding cell efficiency are higher for the ACN/PPN system, attributed to its lower viscosity compared with ACN/MPN system. By using the ACN/PPN (60/40) co-solvent at the presence of TiO2 fillers, gel-state cell with an efficiency of 8.3% can be achieved, which is even higher than that obtained by the liquid state cell (8%). After 500 h test at 60 °C, the cell can retain 95.4% of its initial efficiency.

This study uses graphene oxide quantum dots (GOQDs) to enhance the Li+ -ion mobility of a gel polymer electrolyte (GPE) for lithium-ion batteries (LIBs). The GPE comprises a framework of poly(acrylonitrile-co-vinylacetate) blended with poly(methyl methacrylate) and a salt LiPF6 solvated in carbonate solvents. The GOQDs, which function as acceptors, are small (3-11 nm) and well dispersed in the polymer framework. The GOQDs suppress the formation of ion-solvent clusters and immobilize PF6- anions, affording the GPE a high ionic conductivity and a high Li+ -ion transference number (0.77). When assembled into Li|electrolyte|LiFePO4 batteries, the GPEs containing GOQDs preserve the battery capacity at high rates (up to 20 C) and exhibit 100% capacity retention after 500 charge-discharge cycles. Smaller GOQDs are more effective in GPE performance enhancement because of the higher dispersion of QDs. The minimization of both the ion-solvent clusters and degree of Li+ -ion solvation in the GPEs with GOQDs results in even plating and stripping of the Li-metal anode; therefore, Li dendrite formation is suppressed during battery operation. This study demonstrates a strategy of using small GOQDs with tunable properties to effectively modulate ion-solvent coordination in GPEs and thus improve the performance and lifespan of LIBs.

Fluorescent graphene oxide dots (GODs) are environmentally friendly and biocompatible materials for photoluminescence (PL) applications. In this study, we employed annealing and hydrothermal ammonia treatments at 500 and 140 °C, respectively, to introduce nitrogen functionalities into GODs for enhancing their green-color PL emissions. The hydrothermal treatment preferentially produces pyridinic and amino groups, whereas the annealing treatment produces pyrrolic and amide groups. The hydrothermally treated GODs (A-GODs) present a high conjugation of the nonbonding electrons of nitrogen in pyridinic and amino groups with the aromatic π orbital. This conjugation introduces a nitrogen nonbonding (nN 2p) state 0.3 eV above the oxygen nonbonding state (nO 2p state; the valence band maximum of the GODs). The GODs exhibit excitation-independent green-PL emissions at 530 nm with a maximum quantum yield (QY) of 12% at 470 nm excitation, whereas the A-GODs exhibit a maximum QY of 63%. The transformation of the solvent relaxation-governed π* → nO 2p transition in the GODs to the direct π* → nN 2p transition in the A-GODs possibly accounts for the substantial QY enhancement in the PL emissions. This study elucidates the role of nitrogen functionalities in the PL emissions of graphitic materials and proposes a strategy for designing the electronic structure to promote the PL performance.

This study reports a networked solid polymer electrolyte (N-SPE) containing no solvent, ionic liquid, oligomer, or semisolid additives for lithium-ion batteries (LIBs). The N-SPE comprises a lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt as well as a polymer framework constructed using cage-like polyhedral oligomeric silsesquioxane (POSS) and serving as hubs to network poly(ethylene oxide-co-polypropylene oxide) (P(EO-co-PO)) chains. The networking prevents polymer chain twisting that hinders ion transport. Raman analysis indicates that the POSS hubs improve the dissociation of LiTFSI and localize TFSI− anions. The N-SPE exhibits a low glass transition temperature of −43 °C, a high 25 °C ionic conductivity of 1.1 × 10−4 S cm−1, and a small activation energy of 3.5 kJ mol−1 for ion conduction. The localization of TFSI− results in a high lithium transference number of 0.62, which is determined to be beneficial to Li+ transport. By incorporating the N-SPE into the LiFePO4 cathode and using a free-standing N-SPE membrane, this study assembles a Li|N-SPE|LiFePO4 battery, which delivers a high capacity of 160 mAh g−1 at 25 °C and exhibits excellent charge−discharge cycling stability. The free-standing feature of the N-SPE makes roll-to-roll assembly of LIBs readily scalable for industrial applications.

Poly (vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) and poly (acrylonitrile-co-vinyl acetate) (PAN-VA) are used as gelator to prepare gel- and solid-state polymer electrolytes for dye sensitized solar cells (DSSCs) applications. The electrolytes prepared using PVDF-HFP have higher conductivities than those prepared using PAN-VA. In blended polymers, the conductivities of the electrolytes increase with increasing composition of PVDF-HFP; at 75% PVDF-HFP, conductivity of the blended polymer surpassed that of pure polymers. It is also found that the viscosity of the electrolyte prepared by PAN-VA (1.2 kPaS) is much lower than that by PVDF-HFP (11 kPaS). Therefore, increasing PAN-VA composition can decrease the viscosity of the electrolyte, improving the penetration of electrolytes in the TiO2 matrix. By controlling the ratio of PVDF-HFP/PAN-VA, the conductivity and viscosity of the electrolyte can be regulated and an optimal ratio based on the conversion efficiency of the gel- and solid state DSSCs is obtained at the ratio of 3/1. The highest efficiency achieved by the gel- and solid-state cells using the blending polymers are 6.3% and 4.88%, respectively, which are higher than those prepared using pure polymers (5.53% and 4.56%, respectively). The introduction of TiO2 fillers to the solid electrolyte can further increase the cell efficiency to 5.34%.

Regioregular poly(3-hexyl thiophene) (rr-P3HT) and mixed P3HT/octadecyl amine (ODA) were used as template monolayers to adsorb the gold nanoparticles (AuNPs) dispersed in subphase. The behaviors of P3HT and P3HT/ODA monolayers were investigated by surface pressure area per molecule ( π – A ) isotherms, transmission electron microscopy (TEM) and atomic force microscopy (AFM). The experimental results show that P3HT does not form a homogeneous film and tends to aggregate at the air/water interface. Meanwhile, the amount of AuNPs adsorbed by the P3HT monolayers is low, attributable to the weak interaction between AuNPs and P3HT. By introduction of ODA molecules into the P3HT monolayer, the spreading of P3HT molecules at the air/water interface is improved and the aggregation of P3HT is significantly inhibited. A nearly uniform and homogeneously mixed P3HT/ODA monolayer can be obtained when 50% of ODA is introduced. It is also found that the introduction of ODA can significantly increase the adsorption of AuNPs. For the mixed monolayer with low ratio of ODA (P3HT/ODA = 1/0.2), a higher concentration of adsorbed AuNPs was observed on the corresponding monolayer. However, when the ODA/P3HT ratio increases to 1/1, the AuNPs tend to form three-dimensional (3D) aggregates and the AuNPs cannot distribute well as a homogeneous monolayer. This result is ascribed to the increasing hydrophobicity of the adsorbed AuNPs because of capping of more ODA molecules.

A novel method is developed to prepare orderly arranged mono-molecular layers of poly(3,4-ethylenedioxythiophene) (PEDOT) by surface polymerization of adsorbed 3,4-ethylenedioxythiophene (EDOT) monomers on Au(111) surfaces. To decrease the EDOT-substrate adhesion force, obtaining a highly ordered EDOT monolayer, the adsorption is performed in a phosphate buffer solution (PBS), rather than the acid solutions commonly utilized in the literature. Furthermore, potentials are applied on the electrode to regulate the adsorption rate of EDOT, and to simultaneously control the adsorption/polymerization mechanism of EDOT molecules. According to the observation of an in-situ electrochemical scanning tunneling microscopy (EC-STM), a highly ordered EDOT monolayer can be prepared by performing the adsorption in a PBS solution, as well as by slowly increasing the electrode potential, attributed to the slow adsorption of EDOT. In the following polymerization of the EDOT monolayer, if the reaction is performed at a constant potential (0.5 V vs. Ag/AgCl reference) or in an acid solution, the EDOT in the solution will take part in the reaction on the surface, leading to a disordered and multilayered structure of PEDOT film. Alternatively, by applying cyclic potentials between 0.0 and 0.5 V, as well as the utilization of a PBS solution, the polymerization could perform only on the pre-adsorbed EDOT monolayer, and an ordered PEDOT monolayer can be prepared. Impedance spectroscopy analysis indicates that the ordered PEDOT monolayer has a charge transfer resistance not only much lower than that of an EDOT monolayer, but also lower than that of the disordered PEDOT multilayer.

A new mechanism is proposed against the Grotthuss-type exchange reaction, to interpret the TiO2 nanofiller effect in quasi-solid-state dye-sensitized solar cells. Generally, the inclusion of TiO2 nanofillers in a polymer gel electrolyte causes an enhanced diffusion coefficient and a reduced charge transfer resistance at the electrolyte/counter-electrode interface, thereby improving the photovoltaic performance of the corresponding solar cell. Herein, liquid electrolytes are treated by TiO2 nanoparticles, and the resultant electrolytes yield similar effects on both the electrolyte properties and cell performance. This result suggests a facilitated movement of the triiodide species; however, it cannot be elucidated by the Grotthuss-type mechanism, because of the absence of nanoparticles in such liquid electrolytes. The X-ray photoelectron spectroscopy analysis shows that the TiO2 particles can adsorb iodide ions through their acidic surfaces. The adsorption of iodide ions leads to negatively charged surfaces, which further induces attraction to cations. As a result, cation concentrations in the electrolyte are reduced, and furthermore, the triiodide species can move more easily owing to the attenuated electrostatic interaction with cations. This mechanism is considered to be a dominant reason for the TiO2 nanofiller effect in quasi-solid-state dye-sensitized solar cells.

A novel copolymer, poly(acrylonitrile- co -vinyl acetate) (PAN-VA), is used as the solidification agent to prepare solid-state redox electrolytes for dye-sensitized solar cell (DSSC) applications. TiO 2 nano-particles are used as the fillers to enhance the performance of the solid electrolytes. Furthermore, to improve the penetration of solid electrolytes in the mesoporous TiO 2 matrixes, an external pressure is applied on the electrodes during the solvent evaporation process. The results show that the ionic conductivities of the solid-state electrolytes are comparable with those of gel electrolyte, indicating that the PAN-VA matrix itself may contribute to the charge transfer through the Grotthuss charge transfer mechanism. Based on the temperature-controllable viscosity of the polymer electrolytes, as well as the effect of an applied force, the solid electrolyte can penetrate well in the TiO 2 film, making good contact with the photoelectrode. It is also found that the introduction of TiO 2 fillers does not affect the conductivity of the electrolyte, but greatly enhance the charge transfer at the interface of the electrolyte and Pt counter electrode. On based of the high performance of the electrolyte system, an energy conversion efficiency of 8.65% is achieved for the solid-state DSSC.

Tantalum nitride photoanodes for water splitting are fabricated by anodizing tantalum foils, with subsequent nitridation of the foils in NH3. The as-synthesized Ta3N5 film has n-type conductivity. Loading Co ions during and after the anodization process forms a Ta3N5:Co film consisting of p- and n-type Ta3N5 domains. Both the Ta3N5 and Ta3N5:Co electrodes have a band gap of 2.0 eV. The p–n junctions in the Ta3N5:Co electrode create an internal electrical field favorable for hole transfer from the n-type domains to the p-type domains. When the photoanodes are immersed in a 0.5 M KOH aqueous solution for water splitting with one-sun illumination, the Ta3N5:Co photoanode exhibits photocurrents an order of magnitude higher than those of the bare Ta3N5 photoanode. AC impedance spectroscopy analysis reveals that the p–n junctions formed by Co-doping reduce the interfacial charge transfer resistance by an order of magnitude. The diffuse reflectance spectra of the electrodes indicate that Co incorporation minimizes the defect states in the bulk Ta3N5. Intensity-modulated photocurrent spectroscopy analysis reveals that the high electron transit rate of the Ta3N5:Co electrode can be attributed to its fewer defect states. A photoelectrochemical reaction using the Ta3N5:Co photoanode produces H2 and O2 at a ratio close to 2 : 1, and N2 evolution from the reaction is negligible. The present study demonstrates the establishment of a p–n junction configuration that considerably enhances the performance of nitride anodes in photocatalyzed water splitting.

This study reports on a high ionic-conductivity gel polymer electrolyte (GPE), which is supported by a TiO2 nanoparticle-decorated polymer framework comprising poly(acrylonitrile-co-vinyl acetate) blended with poly(methyl methacrylate), i.e. , PAVM: TiO2. High conductivityTiO2 is achieved by causing the PAVM:TiO2 polymer framework to swell in 1 M LiPF6 in carbonate solvent. Raman analysis results demonstrate that the poly(acrylonitrile) (PAN) segments and TiO2 nanoparticles strongly adsorb PF6(-) anions, thereby generating 3D percolative space-charge pathways surrounding the polymer framework for Li(+)-ion transport. The ionic conductivity ofTiO2 is nearly 1 order of magnitude higher than that of commercial separator-supported liquid electrolyte (SLE).TiO2 has a high Li(+) transference number (0.7), indicating that most of the PF6(-) anions are stationary, which suppresses PF6(-) decomposition and substantially enlarges the voltage that can be applied toTiO2 (to 6.5 V vs Li/Li(+)). Immobilization of PF6(-) anions also leads to the formation of stable solid-electrolyte interface (SEI) layers in a full-cell graphite|electrolyte|LiFePO4 battery, which exhibits low SEI and overall resistances. The graphite|electrolyte|LiFePO4 battery delivers high capacity of 84 mAh g(-1) even at 20 C and presents 90% and 71% capacity retention after 100 and 1000 charge-discharge cycles, respectively. This study demonstrates a GPE architecture comprising 3D space charge pathways for Li(+) ions and suppresses anion decomposition to improve the stability and lifespan of the resulting LIBs.

This study employed real-time in situ STM imaging to examine the adsorption of PEG molecules on Pt(111) modified by a monolayer of copper adatoms and the subsequent bulk Cu deposition in 1 M H(2)SO(4) + 1 mM CuSO(4)+ 1 mM KCl + 88 μM PEG. At the end of Cu underpotential deposition (~0.35 V vs Ag/AgCl), a highly ordered Pt(111)-(√3 × √7)-Cu + HSO(4)(-) structure was observed in 1 M H(2)SO(4) + 1 mM CuSO(4). This adlattice restructured upon the introduction of poly(ethylene glycol) (PEG, molecular weight 200) and chloride anions. At the onset potential for bulk Cu deposition (~0 V), a Pt(111)-(√3 × √3)R30°-Cu + Cl(-) structure was imaged with a tunneling current of 0.5 nA and a bias voltage of 100 mV. Lowering the tunneling current to 0.2 nA yielded a (4 × 4) structure, presumably because of adsorbed PEG200 molecules. The subsequent nucleation and deposition processes of Cu in solution containing PEG and Cl(-) were examined, revealing the nucleation of 2- to 3-nm-wide CuCl clusters on an atomically smooth Pt(111) surface at overpotentials of less than 50 mV. With larger overpotential (η150 mV), Cu deposition seemed to bypass the production of CuCl species, leading to layered Cu deposition, starting preferentially at step defects, followed by lateral growth to cover the entire Pt electrode surface. These processes were observed with both PEG200 and 4000, although the former tended to produce more CuCl nanoclusters. Raising [H(2)SO(4)] to 1 M substantiates the suppressing effect of PEG on Cu deposition. This STM study provided atomic- or molecular-level insight into the effect of PEG additives on the deposition of Cu.

Glucose oxidase (GOx) molecules were adsorbed from aqueous solution onto template monolayer of octadecylamine (ODA) or stearic acid (SA) at the air/liquid interface. The effects of the template layers on the GOx adsorption and the characteristics of the mixed template/GOx monolayers are studied. The monolayers at the air/liquid interface were then transferred onto Pt substrates to prepare GOx Langmuir–Blodgett (LB) films for glucose sensing study. The results show that the SA/GOx monolayer has a pressure–area isotherm resembles that of a SA monolayer, indicating that only a small amount of GOx was incorporated in the mixed film. On the contrary, the ODA/GOx monolayers exhibit high expanded and high compressible characteristics, attributed to the high incorporation amount of GOx induced by the electrostatic interaction between ODA and GOx. The glucose sensing experiments demonstrate that the ODA/GOx LB films have much better performance than SA/GOx films in terms of current sensitivity and current responding rate. Furthermore, an ODA/GOx film prepared after approaching the second equilibrium stage of GOx adsorption (8 h adsorption) shows a better performance than that prepared at the first equilibrium stage. Good linear relationship between response current and glucose concentration was obtained for the GOx-LB films between 0.1 and 5 mM.

Self-assembled monolayers (SAMs) of 3,3′-thiobis(1-propanesulfonic acid, sodium salt) (TBPS) on Au(111) electrodes have been characterized by scanning tunneling microscopy and cyclic voltammetry in aqueous perchloric acid solutions. TBPS exhibits an adsorption behavior typically observed for dialkyl sulfides including intact adsorption and low coverage phases with molecules predominantly lying flat on the surface. On the other hand, an untypical chemical bond and well-ordered domains were determined which resemble the characteristics of alkenethiol SAMs. When the adlayer was prepared at its open circuit potential (OCP), a (6 × 3√3) TBPS adlayer phase was observed at potentials E > 0.7 VRHE in TBPS-free electrolyte. At more cathodic potentials, the adlayer transforms irreversible to a disordered phase. In contrast, in situ STM studies in TBPS-containing electrolyte reveal a very complex, potential-dependent adsorption behavior. With increasing electrode potential, the structure of the adlayer transforms in...

A highly efficient gel-state electrolyte was fabricated by using poly(acrylonitrile -co-vinyl acetate) (PAN–VA) as the gelator of an 3-methoxypropionitrile (MPN)-based liquid electrolyte and was applied in dye-sensitized solar cells (DSSCs). The VA segaments act to dissolve the copolymer into the electrolyte, forming a gel-state structure. The electric conductivity of the gel-state electrolyte is comparable to that of the liquid electrolyte, attributed to the enhancement effect of the AN segments to the dissociation of LiI and 1-propyl-2,3-dimethylimidazolium iodide (DMPII). This effect also leads to a slightly downward shift of the TiO2 conduction band edge toward positive potentials. The energy conversion efficiency of the DSSC achieved by using this gel-electrolyte is 8.34%, which is 97% the value of the liquid-state cell (8.63%).

In situ scanning tunneling microscope (STM) was used to examine the spatial structures of pentacene molecules adsorbed onto a Au(111) single-crystal electrode from a benzene dosing solution containing 16-400 microM pentacene. Molecular-resolution STM imaging conducted in 0.1 M HClO(4) revealed highly ordered pentacene structures of ( radical31 x radical31)R8.9 degrees , (3 x 10), ( radical31 x 10), and ( radical7 x 2 radical7)R19.1 degrees adsorbed on the reconstructed Au(111) electrode dosed with different pentacene solutions. These pentacene structures and the reconstructed Au(111) substrate were stable between 0.2 and 0.8 V [vs reversible hydrogen electrode, RHE]. Increasing the potential to E0.8 V lifted the reconstructed Au(111) surface and disrupted the ordered pentacene adlattices simultaneously. Ordered pentacene structures could be restored by applying potentials negative enough to reinforce the reconstructed Au(111). At potentials negative of 0.2 V, the adsorption of protons became increasingly important to displace adsorbed pentacene admolecules. Although the reconstructed Au(111) structure was not essential to produce ordered pentacene adlayers, it seemed to help the adsorption of pentacene molecules in a long-range ordered pattern. At room temperature (25 degrees C), approximately 100 pentacene molecules seen in STM images could rotate and align themselves to a neighboring domain in 10 s, suggesting that pentacene admolecules could be mobile on Au(111) under the STM imaging conditions of -150 mV in bias voltage and 1 nA in feedback current.

Cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots (QDs) are sequentially assembled onto a nanocrystalline TiO2 film to prepare a CdS/CdSe co-sensitized photoelectrode for QD-sensitized solar cell application. The results show that CdS and CdSe QDs have a complementary effect in the light harvest and the performance of a QDs co-sensitized solar cell is strongly dependent on the order of CdS and CdSe respected to the TiO2. In the cascade structure of TiO2/CdS/CdSe electrode, the re-organization of energy levels between CdS and CdSe forms a stepwise structure of band-edge levels which is advantageous to the electron injection and hole-recovery of CdS and CdSe QDs. An energy conversion efficiency of 4.22% is achieved using a TiO2/CdS/CdSe/ZnS electrode, under the illumination of one sun (AM1.5,100 mW cm−2). This efficiency is relatively higher than other QD-sensitized solar cells previously reported in the literature.

A polysulfide electrolyte considering simultaneously the penetration of the electrolyte in a mesoscopic TiO2 film and the ion dissociation in the solution is developed for application in a CdS-sensitized solar cell (CdS-DSSC). A methanol/water (7:3 by volume) solution was found to be a good solvent for fitting the requirement mentioned above. The optimal composition of the electrolyte, based on the performance of the CdS-DSSCs, was found to contain 0.5 M Na2S, 2 M S, and 0.2 M KCl. By using a photoelectrode prepared after 4 cycles of chemical bath deposition, FTO/TiO2/CdS-4, the efficiency of the CdS-DSSC obtained for this polysulfide electrolyte is 1.15% under the illumination of 100% sun (AM1.5, 100 mW cm−2). This efficiency is less than that obtained using I−/I3− redox couple (1.84%), mainly caused from the smaller values of fill factor and open circuit potential. However, the CdS sensitizer is stable and, furthermore, a much higher short circuit current and IPCE (80%) are obtained by using the polysulfide electrolyte.

An organic solvent, tetrahydrofuran (THF), was employed to modify the Ag anode of a top-emissive polymer light-emitting diode (T-PLED) for improving the hole injection capability and the performance of a T-PLED device. The X-ray photoelectron spectroscope analysis shows that the THF molecules were chemically adsorbed on the Ag surface, forming oxygen-rich species by substrate-catalyzed decomposition. The THF-modification were found to enhance the hole injection on the Ag anode, decrease the threshold voltage, and increase the light intensity and luminous efficiency of a T-PLED device, attributing mainly to the increase of work function of the Ag anode.

Polystyrenesulfonate acid (PSS) and alkyltrimethylammonium bromide (CnTAB, n = 8, 14, or 18) were dissolved in a chloroform/methanol solution and cospread on an air/water interface. The surfactant−...

A novel method is proposed to prepare an ordered array of pentacene adlayer on a Au(111) electrode by self-organization in benzene solution without using an ultra-high-vacuum (UHV) system. Because of the electron-rich characteristic, the pentacene monolayer acts as a template to incorporate electron-accepting fullerenes, forming a stable C60/pentacene complex adlayer. The adlayer structure was investigated by an in situ scanning tunneling microscopy (STM). Two adsorbed structures, (√31 × √13) and (6 × √31), were observed for the pentacene adlayer. For the C60/pentacene complex adlayer, molecular resolution STM revealed two ordered arrays, (2√3 × 2√3)R30° and “in phase” structures, for the C60 molecules respected to the Au(111) substrate. The complex adlayer is stable between operational potential 0.35 and 0.9 V and is able to be decomplexed by selectively removing the fullerenes through the action of a high tip potential (0.75 V). The STM investigation also confirms that the complexation is performed by f...

In-situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV) were used to study the phase evolution of 11-mercapto-1-undecanol (MUO) adlayer on an Au(111) electrode. The effect of various electrolytes, including HClO4 and H2SO4, on the adsorption behavior was studied. The MUO adsorption was found to initiate mainly at the intersectional corner of herringbone rows of an Au(111) reconstruction structure in both of the electrolytes. The following growth of an adsorbed cluster develops first along the face-centered-cubic (fcc) position of the herringbone structure. In the HClO4 solution, the MUO molecule is first adsorbed in a flat-lying orientation when the dose concentration of MUO is low, growing to an ordered domain of striped structure (β phase) with a molecular arrangement of (12 × √3). When the surface coverage becomes high, the hydrocarbon chains of MUO lift off from the Au(111) plane, forming a more condensed and saturated phase, the φ phase, identified as (√3 × √3)R30°. At a high dose con...

Three silane derivatives including dodecyltrichlorosilane (DDTS), phenyltriethoxysilane (PTES) and 3-aminopropyl-methyl-diethoxysilane (APMDS) were used to modify the indium tin oxide (ITO) surfaces. The effects of various terminal groups of the self-assembled monolayers (SAMs) on the growth behavior and interfacial morphologies of N,N′-di(naphthalene-1-yl)-N,N′-diphenylbenzidine (NPB) film deposited on the SAM-modified ITO were studied, as well as their effects on the performance of organic light-emitting diodes (OLED) devices. The results show that the growth behavior of NPB film over-deposited on the SAM-modified ITO is mainly determined by the wettability of the surface. The covering ability and thermal stability of NPB film on the SAM-modified ITO decrease in the order: bare ITO > ITO/PTES > ITO/APMDS > ITO/DDTS. However, the covering characteristic of NPB films on these substrates did not show direct relation to the transport of carriers across the anode/NPB interface as evaluated from the cyclic voltammogram and OLED performance. The turn-on voltages for these SMA-modified OLED devices increase in the order: ITO/PTES