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by Rosalind Sanders solar pool cover blog.

American Institute of Physics displays more productive Selenium photo voltaic cells.

Did you know that many scientists would like to find light-catching components in order to transform more of the sun's power into carbon-free electric power?

A new analysis described in the journal Applied Physics Letters in August 2010 (written and published by the American Institute of Physics), describes how solar power could potentially be collected by using oxide elements that contain the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, embedded selenium in zinc oxide, a relatively cheap material that could make more cost-efficient use of the sun's power.

The team discovered that even a relatively small quantity of selenium, just nine per-cent of the mostly zinc-oxide base, considerably improved the material's effectiveness in absorbing light.

The principal author of this research, Marie Mayer (a fourth-year University of California, Berkeley doctoral student) reveals that photo-electrochemical water splitting, that means employing power from the sun to cleave water into hydrogen and oxygen gases, could potentially be the most exciting future application for her labor. Managing this reaction is key to the eventual creation of zero-emission hydrogen powered motors, which hypothetically will run only on water and sunlight.

Journal Research: Marie A. Mayer et all. Applied Physics Letters, 2010

The conversion productivity of a PV cell is the percentage of sunlight energy that the photo voltaic cell converts to electrical power. This is very important when discussing PV devices, because improving this efficiency is vital to making Photovoltaic electricity competitive with more standard sources of energy (e.g., classic fuels).

For comparison, the earliest Pv products converted about 1%-2% of sunlight power into electric energy. Today's Pv devices convert 7%-17% of light energy into electrical energy. Of course, the other side of the equation is the dollars it costs to produce the PV devices. This has been improved over the years as well. In fact, today's PV systems make electricity at a fraction of the cost of early PV systems.

In the 1990s, when silicon cells were twice as thick, efficiencies were much smaller than nowadays and lifetimes were reduced, it may well have cost more energy to produce a cell than it could generate in a lifetime. In the meantime, the technological innovation has moved on substantially, and the energy repayment time (defined as the recovery time needed for generating the energy spent to manufacture the respective technical energy systems) of a modern photovoltaic module is generally from 1 to 4 years depending on the module type and location.

Usually, thin-film technologies - despite having comparatively low conversion efficiencies - obtain significantly shorter energy repayment times than conventional systems (often < 1 year). With a typical lifetime of 20 to 30 years, this signifies that current solar cells are net energy producers, i.e. they produce significantly more energy over their lifetime than the energy expended in producing them.

About the author - Rosalind Sanders shares knowledge for the solar pool cover blog, her personal hobby web log focused on suggestions to help home owners to spend less energy with solar energy.

 

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