American institute of physics displays us more economical Selenium photo voltaic cells
Did you know that many researchers would like to find light-catching elements in order to transform more of the sun's power into carbon-free electricity?
A new analysis announced in the journal Applied Physics Letters in August this year (released by the American Institute of Physics), describes how solar power could potentially be collected by using oxide elements that include the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, inserted selenium in zinc oxide, a relatively economical material that could make more efficient use of the sun's energy.
The team identified that even a relatively small quantity of selenium, just 9 percent of the mostly zinc-oxide base, significantly increased the material's productivity in absorbing light.
The key author of this analysis, Marie Mayer (a fourth-year College of California, Berkeley doctoral student) affirms that photo-electrochemical water splitting, that means using energy from the sun to cleave water into hydrogen and oxygen gases, could possibly be the most stimulating future application for her efforts. Managing this reaction is key to the eventual generation of zero-emission hydrogen powered automobiles, which hypothetically will run only on water and sunlight.
Journal Reference: Marie A. Mayer et all. Applied Physics Letters, 2010 [link: http://link.aip.org/link/APPLAB/v97/i2/p022104/s1]
The conversion productivity of a PV cell is the portion of sunlight energy that the photo voltaic cell converts to electricity. This is very important when discussing Photo voltaic devices, because increasing this efficiency is vital to making Pv electricity competitive with more common sources of energy (e.g., classic fuels).
For comparison, the initial Photo voltaic units converted about 1%-2% of sunlight energy into electrical energy. Today's Photo voltaic products convert 7%-17% of light energy into electric energy. Of course, the other side of the equation is the dollars it costs to produce the PV devices. This has been enhanced over the years as well. In fact, today's PV systems generate 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 today and lifetimes were shorter, it may well have cost more energy to make a cell than it could generate in a lifetime. In the meantime, the technological innovation has moved on considerably, and the energy repayment time (defined as the recovery time required for generating the energy spent to make 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 - achieve substantially shorter energy repayment times than conventional systems (often < 1 year). With a common lifetime of 20 to 30 years, this signifies that contemporary photo voltaic cells are net energy producers, i.e. they generate significantly more energy over their lifetime than the energy expended in producing them.
The author - Rosalind Sanders publishes articles for the pool solar covers review blog, her personal hobby website centered on guidelines to help home owners to save energy with solar power.