Ionic compounds and uses thereof

Abstract

There are provided compounds of formulas (IV), and (IVa): Various chemical entities can be used for R4, R5, R6, and R12. These compounds can be particularly useful as anti-static agents or for preparing redox couples.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application claims priority on U.S. provisional application No. 60 / 635,015 filed on Dec. 13, 2004, which is incorporated herein by reference in its entirety.TECHNICAL FIELD [0002] The present invention relates to improvements in the field of electrochemistry. In particular, this invention relates to compositions that can be used for various purposes such as anti-static agents or for preparing redox couples or reversible switchable systems. BACKGROUND OF THE INVENTION [0003] Sun is a free and unlimited renewable source of energy. It can be converted directly to electricity by using p-n heterojunction solar cells (like silicon-based devices), electrochemical photovoltaic cells (EPC's) or dye-sensitized solar cells (DSSC 's). EPC's are systems based on a junction between a semiconductor (p-type or n-type) and an electrolyte containing one redox couple; an auxiliary electrode completes the device. Owing to the built-in potential ...

AI Technical Summary

Benefits of technology

"The invention relates to a composition comprising two different compounds that can be used in a variety of applications. The first compound is selected from a group of formulas (I), (III), and (V), while the second compound is selected from a group of formulas (II), (IV), and (VIII). The two compounds can be used alone or in combination with each other. The compounds have specific structures and can be used in various applications such as in the production of polymers, adhesives, and coatings. The patent text also describes the properties of the compounds and how they can be used in different industries."

Problems solved by technology

However, one main issue still to resolve is to find a redox couple that is electrochemically stable, non-corrosive, with a high degree of reversibility and a high electropositive (in conjunction with n-type semiconductors) or electronegative (in conjunction with p-type semiconductors) potential, and colorless when used in concentrations allowing high electrolyte ionic conductivities.

The main limitations of this system are (i) the fact that it absorbs a significant part of the visible light of the solar spectrum when used in the concentration range giving reasonably good ionic conductivities (which leads to a decrease in the energy conversion efficiency); (ii) its too low redox potential (which limits the device photovoltage); (iii) its reactivity towards silver (which prevents the use of this metal as a current collector); and (iv) the high volatility of the electrolyte when usual organic solvents are employed (which causes an irreversible instability of the device).

Moreover, regeneration of the dye molecules by the reduced species (CoII) (absolutely necessary to the operation of the device) may become more difficult due to association of the oxidized species (CoIII) with the sensitizer.

In EPC's, various redox couples dissolved in water were studied, such as Fe(CN)64− / Fe(CN)63−, I− / I3−, Fe2+ / Fe3+, S2− / Sn2−, Se2− / Sen2− and V2+ / V3+, and devices exhibiting a good energy conversion efficiency were generally unstable under sustained white light illumination due to photocorrosion of the semiconductor electrode.

The use of non-aqueous electrolytic media (liquid, gel or polymer) could eliminate the photocorrosion process, but in these cases the number of redox couples is very limited.

In addition to the coloration and potential problems occurring with the I− / I3− couple, as mentioned above, the device stability has not been demonstrated.

Furthermore, its solubility is not very good in organic media.

Thus, based on prior art relative to redox couples for EPC's and DSSC'S, there are no redox couples permitting to considerably optimize the device energy conversion efficiency.

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