Development of a simple analytical method to determine arsenite using a DNA aptamer and gold nanoparticles.

A simple analytical method was developed to determine the arsenite (As(III)) concentration using a DNA aptamer and gold nanoparticles (AuNPs). Prior to sample measurements, the method sensing mechanism was confirmed by analyzing the particle size of the AuNPs at each step of the analysis procedure, and the key operational parameters that affect the method performance were optimized. The optimal final NaCl concentration, incubation time with NaCl and pH of a 3-(N-morpholino) propanesulfonic acid buffer were 60 mM, 10 min and 7.3, respectively. A calibration curve was created under optimized operational conditions. The calibration curve was linear from a 1.0- to 10-µM As(III) concentration. The detection limit was 2.1 µM (161 µg/L). Using the calibration curve, we evaluated groundwater samples spiked with As(III). As(III) concentrations in groundwater pretreated with a 0.2-µm-pore-size membrane filter and cation-exchange resin were determined by using the method, which suggests that the proposed method can be used to determine the As(III) concentration in groundwater.

Dependence of the efficiency improvement of black-dye-based dye-sensitized solar cells on alkyl chain length of quaternary ammonium cations in electrolyte solutions.

Dependence of the suppression of the backward electron transfer reaction from the TiO2 photoelectrode to I3(-) in the electrolyte on the alkyl chain length of the quaternary ammonium cation has been investigated for further efficiency improvement of high-performance cosensitized dye-sensitized solar cells (DSCs). The tetraheptylammonium cation was found to be more effective than the tetraethylammonium and tetrabutylammonium cations for the suppression of the backward electron transfer reaction without changing the conduction band energy of TiO2. 12.0% conversion efficiency, which is the second highest efficiency for DSCs based on ruthenium sensitizers, was achieved in the cosensitized DSC with Black dye and D131 by using an electrolyte solution containing a moderate concentration of tetraheptylammonium iodide.

Effective enhancement of the performance of black dye based dye-sensitized solar cells by metal oxide surface modification of the TiO2 photoelectrode.

Effective enhancement of the performance of black dye based dye-sensitized solar cells has been achieved by MgO or Al(2)O(3) surface modification of the TiO(2) photoelectrode. The conversion efficiency was improved from 10.4% to 10.8% due to the blocking effect of the thin overlayer at the TiO(2) surface.

Characterization of photovoltaic performance of the dye-sensitized solar cell with a novel ruthenium complex having a bisdemethoxycurcumin as a ligand.

The first example of a ruthenium sensitizer (TUS-22) having a natural dye, bisdemethoxycurcumin, as a ligand has been synthesized. The dye-sensitized solar cell based on this novel dye showed 5.8% conversion efficiency under AM 1.5 (100 mW/cm(2)) irradiation.