In this study, we found that the open-circuit voltage (V_oc) of dye-sensitized solar cells was improved by using interhalogen ions (XY₂⁻; X, Y = I or Br) synthesized by mixing iodide and bromide redox couples. I⁻ ions are important for obtaining a higher short-circuit current (J_sc) in the bromine-based electrolyte. The charge transfer and diffusion resistances were determined by electrochemical impedance spectroscopy. The interhalogen redox mediators improved the photoenergy conversion efficiency (PCE) and achieved a high V_oc of 0.91 V.

The void defect inside the electroformed nickel microcolumns is a common problem affecting the performance of the microsystem. In this study, a simulation model for the dynamic deposition of microcolumns is set up to clarify the changing characteristics of ion mass transfer and electric field distribution inside the microcavities under the electroforming process, with the aim of revealing the formation mechanism of the void effect. The simulation results show that the dynamic aspect ratio (DAR) of the microcavity increases from the initial 2 : 1 to infinity during the electroforming process. As a result, the ion mass transfer within the microcavity decreases, resulting in a gradual deterioration in the uniformity of the nickel ion concentration distribution along the microcavity sidewall. The increased difference in the electrolyte potential along the microcavity sidewall leads to a reduction in the uniformity of the overpotential distribution. These two factors lead to a faster deposition rate at the open side of the microcavities, and consequently to the formation of a void defect inside the microcolumn. Compared to the overpotential distribution, the nickel ion concentration distribution plays a dominant role in the size of the void defect. Aiming to eliminate the void defect, several approaches have been carried out to improve the uniformity of the nickel ion concentration distribution inside the microcavity. The experimental results show that compared to a high current density (1 A/dm²), the low current density (0.25 A/dm²) helps to reduce the ion consumption rate, thus contributing to a uniform distribution of nickel ion concentration, as well as a reduced void defect size. The pulse reverse current proves effective in eliminating the effects of the nonuniform distribution of the ion concentration and the overpotential on the microcavity deposition and realized the defect-free electroforming of the microcolumn with a width of 30 µm and a height of 60 µm.

In this paper, an ionic liquid (IL) was dripped onto a reduced graphene oxide (R-GO) and composite-modified glassy carbon electrode (GCE) used as an electrochemical sensor. The sensor was used to detect the lead and cadmium ions codeposited with bismuth ions in rice by differential pulse voltammetry. The method exhibited good linearity and perfect applicability. The developed sensor was used to determine the contents of lead and cadmium in rice, and the results were compared with those of the certified method; there was no significant difference between the developed sensor and the certified method at the 95 % confidence level, so the method could be applied in practice.

Coulometric determination of perfluorooctane sulfonate (PFOS⁻) and perfluorohexanesulfonate (PFHxS⁻), which are ionic perfluoroalkyl substances (PFAS ion), was demonstrated with a thin-layer electrolysis flow cell for the ion transfer (flow-TLECIT). Flow-TLECIT has a simple structure consisting of a Ag/AgCl plate electrode, a spacer with a flow path for aqueous sample solution, an organic liquid membrane hold in the porous membrane, and the conducting polymer paste-coated carbon electrode. The conductive polymer paste was made of poly(3,4-ethylenedioxythiophene) modified with lauryl-terminated bispoly(ethyleneglycol) (PEDOT-PEG) for screen-printing the conducting polymer on the carbon electrode. Flow-TLECIT achieved the complete mass transfer of PFAS ion from the aqueous sample solution to the organic membrane under applying a constant potential between the Ag/AgCl plate electrode and the conducting polymer paste-coated carbon electrode and detects the transfer of PFAS ion as current. The integrated current (electrical charge) can be converted to the mole amount of PFAS ion. For PFHxS⁻, the evaluated amount was 97 %–103 % of the theoretical mole amount in the concentration range of 5–200 µM and the repeatability in the same cell were ±1 %–±5 % (n = 8). For PFOS⁻, the evaluated amount was 102 % of the theoretical mole amount in the concentration of 18.3 µM and the repeatability in the same cell is ±4 % (n = 3). Flow-TLECIT has advantages such as (1) the flow system suitable for continuous measurement, (2) a simple and inexpensive device, and (3) calibration-free.