Cu­(I)/(II) complex redox couples in dye-sensitized solar cell (DSSC) are of particular interest because of their low reorganization energy between Cu­(I) and Cu­(II), which minimizes the potential loss during sensitizer regeneration, thus allowing the open-circuit voltage of the device to go over 1.0 V. However, Cu­(I)/(II)-based redox couples are reported to coordinate with 4-tert-butylpyridine (TBP), which is a standard additive in the electrolyte, and this is believed to account for the poor durability of a Cu­(I)/(II)-based DSSCs. Despite TBP coordination on Cu­(I)/(II) complexes are confirmed in the literature, its detailed mechanism is yet to be directly proven. In addition, how TBP coordination with Cu­(I)/(II) complexes affects the stability of the device is never reported. Here, we choose bis­(2,9-dimethyl-1,10-phenanthroline) copper­(I)/(II) ([Cu­(dmp)2 2+/+]) as the modeling redox couple to investigate its interaction with TBP. It is found that [Cu­(dmp)2 +] is resistive to TBP coordination but could form three new TBP-coordinated compounds. Moreover, it is also confirmed their electrochemical activity on Pt catalyst and mass transfer capability are both demoted significantly. As a result, serious fill factor loss is observed on the stability trail while short-circuit current density and open-circuit voltage are relatively unaffected. This unique degradation pattern may resemble a feature of Cu­(I)/(II)-based redox couple after TBP poisoning.

No abstract

In this work, we have synthesized a novel porphyrin dye named SK7, which contains two N,N-diarylamino moieties at two β-positions as electron-donating units and one carboxy phenylethynyl moiety at the meso-position as an electron-withdrawing, anchoring group. This novel dye was tested for the application in dye-sensitized solar cells. The light-harvesting behavior of SK7 and YD2 was investigated using UV–vis absorption and density functional calculation. The electron transport properties at the TiO2/dye/electrolyte interface for SK7- and YD2-based devices were evaluated by electrochemical impedance spectroscopy. X-ray crystallographic characterization was conducted to understand the influence of two N,N-diarylamino units at two β-positions. The power conversion efficiencies of ca. 6.54% under 1 sun illumination (AM 1.5G) and ca. 19.72% under a T5 light source were noted for the SK7 dye. The performance of SK7 is comparable to that of dye YD2, which contains only one N,N-diarylamino moiety at the meso-position (ca. 7.78 and 20.00% under 1 sun and T5 light, respectively).

A multimode ratiometric Hg2+ selective chemosensor based on a carbazole–thiobarbituric acid conjugate was developed. It responds to the presence of Hg2+ by colorimetry and by fluorescence. The sensor action is demonstrated in both aqueous homogeneous or microheterogeneous media.

Amino-terminated silane compound modification was wet-processed on a silicon wafer using four different solvents to investigate the property of the self-assembled monolayer (SAM) and its influence on the adhesion of electroless deposited nickel–phosphorus (Ni–P) films. Analyzed by various tools including dynamic light scattering, the atomic force microscope, X-ray photoelectron spectroscopy, inductively coupled plasma with mass spectroscopy, a proper link between the processing solvent and SAM quality is established. It is found that at least the chemical compatibility, the polarity, and the acidity of solvents can affect the final morphology of the resultant SAM. Unlike toluene and ethanol that are most frequently chosen in literature, we conclude that isopropyl alcohol (IPA) is a superior solvent for amino-terminated silane compounds. Owing to the good SAM quality formed in IPA, the adhesion of electroless deposited Ni–P films is largely strengthened, even as high as the bulk strength of silicon wafers.