Electrochemical Synthesis of Novel Zn-Doped TiO Nanotube/ZnO Nanoflake Heterostructure with Enhanced DSSC Efficiency.

Abstract: The paper reports the fabrication of Zn-doped TiO nanotubes (Zn-TONT)/ZnO nanoflakes heterostructure for the first time, which shows improved performance as a photoanode in dye-sensitized solar cell (DSSC). The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy, scanning electron microscopy, and X-ray diffractometer. The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency, over pure TiO photoanodes.

A novel cost effective fabrication technique for highly preferential oriented TiO2 nanotubes.

Single crystal like TiO(2) nanotubes with preferential orientation along the [001] direction, parallel to the growth direction of nanotubes, that offer ease of charge transport much higher than reported so far, are fabricated using a cost effective two step technique. The success of this method to grow the nanotubes with the anomalous intense [001] preferential orientation is attributed to the zinc assisted minimization of the (001) surface energy. The single crystal like TiO(2) nanotubes show superior performance as supercapacitor electrodes compared to the normal polycrystalline titanium dioxide nanotubes.

Micellar control of the photooxidation pathways of 10-methyl phenothiazine: electron versus energy transfer mechanisms.

10-Methyl phenothiazine (MPS) was chosen as a model compound to investigate the effects of compartmentalisation and of charged interfaces on the primary mechanisms involved in the phototoxic reactions related to phenothiazine drugs. Two most important pathways resulting from the interaction of the triplet excited state of MPS ((3)MPS*) with molecular oxygen ((3)O2) have to be considered: (i) energy transfer producing singlet oxygen ((1)O2) and (ii) electron transfer generating the superoxide anion (O2˙(-)) and the radical cation (MPS˙(+)). The quantum yields of (1)O2 production by MPS solubilized in the dispersed pseudo-phase of aqueous micellar systems were found to be similar to those determined in solvents of various polarities, regardless of the anionic or cationic nature of the surfactant (SDS or CTAC).

Self sensitized photooxidation of N-methyl phenothiazine: acidity control of the competition between electron and energy transfer mechanisms.

The reaction pathways following electronic excitation of 10-methyl phenothiazine (MPS) in the presence of oxygen have been investigated as a contribution to establish the mechanisms involved in the phototoxic reactions related to phenothiazine drugs. In the context of previously published results, the pathways of oxidation via the radical cation and/or by reactive oxygen species, such as singlet oxygen and superoxide anion, are of particular interest. The effects of polarity of the medium as well as of proton donors on the different reaction pathways, in particular on the formation of reactive oxygen species and the intermediates of the oxidation of 10-methyl phenothiazine, have been investigated.