Shinji Murai

Quasi-solid dye-sensitized solar cells containing chemically cross-linked gel: How to make gels with a small amount of gelator

Quasi-solid dye-sensitized solar cells equipped with chemically cross-linked gels are reported. The gelator contains multi-functional pyridine or imidazole derivatives and multifunctional halogen derivatives. The former reacts with the latter to give three-dimensional ionomer structures even in liquid electrolytes. Gelators polymerized directly in liquid electrolytes of cells have not been reported so far. This makes the cell fabrication process easier, where electrolyte precursors are injected into cells, followed by gelled directly in the cells. In addition, a micro-phase separation technique is introduced in order to decrease the amount of gelators. This makes it possible for the liquid electrolytes to be solidified without losing the high performance of liquid-type cells before gelation.

Quasi-solid dye sensitised solar cells filled with phase-separated chemically cross-linked ionic gels

Quasi-solid dye sensitised solar cells were prepared by gelling ionic liquid electrolytes with phase-separated chemically cross-linked gels which make it possible to solidify DSSC without losing the performance of the parent DSSC.

Novel latent initiator for cationic polymerization of epoxides

A novel latent initiator for cationic polymerization of epoxides, a composite catalyst containing aluminum complexes and phenol derivatives protected with tert-butoxycarbonyl groups (tBOC), is reported. At a certain temperature, protected phenols generate the parent phenols which are coinitiators with aluminum complexes. The deprotection temperature of the tBOC group depends on the structure of the phenol moieties. Bis(p-t-butoxycarbonyloxyphenyl)sulfone (Ph1) generates (p-dihydroxyphenyl)sulfone (PhH1) at around 150°C, the temperature at which the curing of epoxides is conventionally carried out. The thermally generated PhH1 and aluminum complexes initiate the curing of epoxides. Epoxy resin compositions containing these composite catalysts have a long shelf life at room temperature and are cured at around 150°C, showing that the composite catalyst has excellent latent properties.

Quasi-solid dye-sensitized solar cells: control of TiO2-gel electrolyte interfaces

Quasi-solid dye sensitized solar cells (Q-DSSC) were fabricated by employing gel electrolytes containing ionic liquids and gelators. Sufficient physical contacts between nano-crystalline TiO2 particles and gel electrolytes in nano-porous TiO2 layers were achieved by solidifying gel electrolyte precursors after the cells are filled with the electrolytes. Photo-currents increased largely by embedding carboxylic acids among dye molecules on TiO2 crystals. The nano-porous TiO2 electrolytes were fabricated by dipping the dye anchored TiO2 substrates in dilute solutions of carboxylic acids. It was found that resistances in the TiO2 layers decreased by these treatments.

Oxygen-crosslinked polysilane: the new class of Si-related material for electroluminescent devices

The preparation and optical properties of the novel silicon-related material named oxygen-crosslinked polysilane were investigated. The oxygen-crosslinked polysilane was prepared by the thermal annealing of the precursor polysilane bearing alkoxyl groups. The photoluminescence consisting of a broad visible band at about 440u2009nm and a relatively sharp band at about 360u2009nm was observed at room temperature. The relative intensities of the visible emission were changed during the crosslinking. The visible emission was greatly affected by the steric hindrance of the alkoxyl groups of the precursor. The visible electroluminescene (EL) was also observed uniformly from the EL cell consisting of the oxygen-crosslinked polysilane film sandwiched between A1 electrode and indium-tin-oxide (ITO) electrode. The current densities of the EL cell increased with an increase in the oxygen-crosslinking.