Photoelectrochemical cell

Photoelectrochemical cells or PECs are solar cells and extract electrical energy from light, including visible light. Each cell consists of a semiconducting photoanode and a metal cathode immersed in an electrolyte.

Some photoelectrochemical cells simply produce electrical energy, while others produce hydrogen in a process similar to the electrolysis of water.

Photogeneration cell

In this type of photoelectrochemical cell, electrolysis of water to hydrogen and oxygen gas occurs when the anode is irradiated with electromagnetic radiation. This is also referred to as artificial photosynthesis and has been suggested as a way of converting solar energy into a transportable form, namely hydrogen.

There are two types of photochemical systems with photocatalysis, one that use semiconductor surfaces as catalysts (the semiconductor surface absorbs solar energy and acts as an electrode for water splitting) the other uses in-solution metal complexes as catalysts (When the dissolved metal complex absorbs energy, it creates an electric charge separation that drives the water-splitting reaction) [ [http://www.hnei.hawaii.edu/h2_appendix.pdf Assessing the Feasibility of Hydrogen and Fuel Cells in Hawaii Pag.3] ] .

The photogeneration cells passed the 10 percent economic efficiency barrier. Lab tests confirmed the efficiency of the process. The main problem is the corrosion of the semiconductors which are in direct contact with water [ [http://today.slac.stanford.edu/feature/hydrogen2.asp 2006 - Slac] ] .Research is going on to meet the United States Department of Energy requirement, a service life of 10000 hours.

Graetzel cell

Graetzel cells or dye-sensitized solar cells; these cells use dye-adsorbed highly porous nanocrystalline titanium oxide (nc-TiO₂) to produce electrical energy.

History

*1967 Akira Fujishima discovers the Honda-Fujishima effect.

ee also

*Photohydrogen
*Artificial photosynthesis
*Glossary of fuel cell terms
*Photodissociation
*Photoelectrolysis
*Photosynthesis
*Photochemical reaction
*Photochemistry
*Timeline of hydrogen technologies;Other third generation solar cells
*Nanocrystal solar cell
*Polymer solar cell

References

Further reading

*Michael Gratzel. Photoelectrochemical Cells. Nature, Vol 414, 15 November 2001.
*Michael Gratzel. Solar Energy Conversion By Dye-Sensitized Photovoltaic Cells. Inorganic Chemistry, 2005, vol 44, 6841-6851.
*Juan Bisquert, David Cahen, Gary Hodes, Sven Ru1hle, and Arie Zaban. Physical Chemical Principles of Photovoltaic Conversion with Nanoparticulate, Mesoporous Dye-Sensitized Solar Cells. J. Phys. Chem. B 2004, 108, 8106-8118

External links

* [http://www.hydrogen.energy.gov/pdfs/review08/pdp_15_misra.pdf EERE-Photoelectrochemical Generation of Hydrogen Using Heterostructural Titania Nanotube ArraysMano]
* [http://www.wired.com/news/technology/0,1282,65936,00.html Wired]