Rational Construction of 2D Fe O @Carbon Core-Shell Nanosheets as Advanced Anode Materials for High-Performance Lithium-Ion Half/Full Cells.

Transition metal oxides have vastly limited practical application as electrode materials for lithium-ion batteries (LIBs) due to their rapid capacity decay. Here, a versatile strategy to mitigate the volume expansion and low conductivity of Fe O by coating a thin carbon layer on the surface of Fe O nanosheets (NSs) was employed. Owing to the 2D core-shell structure, the Fe O @C NSs exhibit significantly improved rate performance and cycle capability compared with bare Fe O NSs.

2-Dinaphthopentacene: A Polycyclic Aromatic Hydrocarbon Core for Metal-Free Organic Sensitizers in Efficient Dye-Sensitized Solar Cells.

Continuous studies on the use of a polycyclic aromatic hydrocarbon as the central block of an organic photosensitizer have brought forth a new opportunity toward efficiency enhancement of dye-sensitized solar cells (DSCs). In this paper, a nonacyclic aromatic hydrocarbon 9,19-dihydrodinaphtho[3,2,1-:3',2',1'-]pentacene, tethered with four 4-hexylphenyl solubilizing groups is reported. The novel chromophore 9,9-19-19-tetrakis(4-hexylphenyl)-9,19-dihydrodinaphtho[3,2,1-:3',2',1'-]pentacene is further functionalized with diarylamines and 4-(7-ethynylbenzo[][1,2,5]thiadiazol-4-yl)benzoic acid to produce two donor-acceptor (D-A) organic photosensitizers, achieving good power conversion efficiencies up to 10.

Integrated hydrogen evolution and water-cleaning via a robust graphene supported noble-metal-free FeCoS system.

In an electrocatalytic hydrogen evolution reaction (HER) system, a cathodic H resource, an anodic sacrificial agent and a robust catalyst are three essential factors. Industry wastewater emissions, containing high levels of acidity and organic dyes, actually can satisfy the material requirements for the HER. Herein, a new HER method is proposed, taking acidic ions from wastewater as a cathodic resource to produce H, while organic dye waste acts as an anodic sacrifice to balance the reaction.

Correlating excited state and charge carrier dynamics with photovoltaic parameters of perylene dye sensitized solar cells: influences of an alkylated carbazole ancillary electron-donor.

Two perylene dyes characteristic of electron-donors phenanthrocarbazole (PC) and carbazyl functionalized PC are selected to study the complicated dynamics of excited states and charge carriers, which underlie the photovoltaic parameters of dye-sensitized solar cells (DSCs). We have combined femtosecond fluorescence up-conversion and time-resolved single-photon counting techniques to probe the wavelength-dependent photoluminescence dynamics of dye molecules not only dissolved in THF but also grafted on the surface of oxide nanoparticles. Excited state relaxation and electron injection both occur on a similar timescale, resulting in a very distributive kinetics of electron injection.

Design of two electrode system for detection of antioxidant capacity with photoelectrochemical platform.

Recently, a flow photoelectrochemical cell has been first developed and applied to assay global antioxidant capacity in our group. Yet, shortcomings of liquid reference electrode such as sample contaminations from the leaking of the reference solution, mechanically fragile, temperature and light sensitivity, etc. are significant restrictions for integration and miniaturization of photoelectrochemical sensing instruments, which have greatly limited their practical applications.

Convenient recycling of 3D AgX/graphene aerogels (X = Br, Cl) for efficient photocatalytic degradation of water pollutants.

3D AgX/graphene aerogel (GA) composites (X = Br, Cl) are synthesized. Not only is the photocatalytic performance increased in comparison with pristine AgX, but also the photocatalytic cycling process is facilitated just using tweezers Thus, the comprehensive performance of the AgX/GA composites provides robust support for future industrial applications of the photocatalyst.

Biomolecule-free, selective detection of o-diphenol and its derivatives with WS2/TiO2-based photoelectrochemical platform.

Herein, a novel photoelectrochemical platform with WS2/TiO2 composites as optoelectronic materials was designed for selective detection of o-diphenol and its derivatives without any biomolecule auxiliary. First, catechol was chosen as a model compound for the discrimination from resorcinol and hydroquinone; then several o-diphenol derivatives such as dopamine, caffeic acid, and catechin were also detected by employing this proposed photoelectrochemical sensor. Finally, the mechanism of such a selective detection has been elaborately explored.

Rapid and specific sensing of gallic acid with a photoelectrochemical platform based on polyaniline-reduced graphene oxide-TiO2.

A novel photoelectrochemical sensor has been designed with polyaniline-reduced graphene oxide-titanium dioxide, which was further applied to sense gallic acid and exhibited extraordinary rapid response, high sensitivity and excellent anti-inference. Meanwhile, the mechanism has been elaborately explored.

The factors influencing nonlinear characteristics of the short-circuit current in dye-sensitized solar cells investigated by a numerical model.

A numerical model for interpretation of the light-intensity-dependent nonlinear characteristics of the short-circuit current in dye-sensitized solar cells is suggested. The model is based on the continuity equation and includes the influences of the nongeminate recombination between electrons and electron acceptors in the electrolyte and the geminate recombination between electrons and oxidized dye molecules. The influences of the order and rate constant of the nongeminate recombination reaction, the light-absorption coefficient of the dye, the film thickness, the rate constant of geminate recombination, and the regeneration rate constant on the nonlinear characteristics of the short-circuit current are simulated and analyzed.

Bionic radical generation and antioxidant capacity sensing with photocatalytic graphene oxide-titanium dioxide composites under visible light.

OH radicals as reactive oxygen species in an organism were applied to assay antioxidant capacity since the obtained results present high biological relevance. As a proper photocatalyst, titanium dioxide was employed to generate OH radicals under ultraviolet light irradiation. However, ultraviolet light can damage molecular probe (DNA or protein) during the detection of antioxidant capacity, which interferes with the results.

Coupled analysis of steady-state and dynamic characteristics of dye-sensitized solar cells for determination of conduction band movement and recombination parameters.

A new research strategy for determining the conduction band movement of TiO(2) films and charge recombination between electrons in the TiO(2) film and electron acceptors in the electrolyte was proposed. Steady-state short-circuit current density versus open-circuit voltage was employed to attain the exchange current density and recombination reaction order. Transient photovoltage decay and open-circuit voltage decay measurements were carried out to obtain the energetic distribution of trapped electrons.

Improvement in the assessment of direct and facilitated ion transfers by electrochemically induced redox transformations of common molecular probes.

A new strategy based on a thick organic film modified electrode allowed us, for the first time, to explore the voltammetric processes for a series of hydrophilic ions by electrochemically induced redox transformations of common molecular probes. During the limited time available for voltammetry, this thick organic film ensured that the generated product of the molecular probe, which is within a limited diffusion layer, was kept far away from the aqueous-organic solvent interface; therefore, regardless of the degree of hydrophobicity, the generated product never participates in ion exchange across the interface and the charge neutrality of the organic film (containing an extremely hydrophobic electrolyte) can only be maintained by the injection of ions from the aqueous phase. Taking advantage of this fact, common redox probes, such as ferrocene (Fc) and 7,7,8,8-tetracyanoquinodimethane (TCNQ), which are almost useless for both three-phase electrode (TPE) and thin-layer cyclic voltammetry (TLCV) methods, can induce the transfer of numerous highly hydrophilic anions and cations.

Influences of cation charge density on the photovoltaic performance of dye-sensitized solar cells: lithium, sodium, potassium, and dimethylimidazolium.

We investigate the dependence of the photovoltaic performance of dye-sensitized solar cells on the cations with different charge densities, such as lithium (Li(+)), sodium (Na(+)), potassium (K(+)), and dimethylimidazolium (DMI(+)). The efficiencies of light harvesting, electron injection and charge collection were evaluated to clarify the influence of cation selection on photocurrent generation. It is found that the short-circuit photocurrents of DSCs gradually diminish with decreasing cation charge densities, partially owing to reduced electron injection rates which are intimately related to the reaction Gibbs free energies.

Which mechanism operates in the electron-transfer process at liquid/liquid interfaces?

We present a more general expression for the relationship of potential dependence, which implies that a change in the interfacial drop across the interface has little effect on the free energy of the reaction, but mainly affects the surface concentration of reactant in each phase. Abundant experimental results from several well-known groups are analyzed in great detail to confirm our conclusion. At the same time, we define a new parameter named Frumkin correction factor to describe this relationship of potential dependence, which expresses the thermodynamic effect of double diffuse layers within both phases in contrast with the so often suggested kinetic electron-transfer (ET) coefficient; we also find that it depends on two intimately related aspects: the charges of reactive species and the ratio of the diffuse layer potential to the total potential within each phase, so it is quite arbitrary to ignore the diffuse layer effect in the aqueous phase just because of its relatively small values.

Real-time PCR microfluidic devices with concurrent electrochemical detection.

Electrochemistry-based detection methods hold great potential towards development of hand-held nucleic-acid analyses instruments. In this work, we demonstrate the implementation of in situ electrochemical (EC) detection method in a microfluidic flow-through EC-qPCR (FTEC-qPCR) device, where both the amplification of the target nucleic-acid sequence and subsequent EC detection of the PCR amplicon are realized simultaneously at selected PCR cycles in the same device. The FTEC-qPCR device utilizes methylene blue (MB), an electroactive DNA intercalator, for electrochemical signal measurements in the presence of PCR reagent components.