Technology
About Photovoltaics
Photovoltaics (PV) or solar cells as they are often referred to, are semiconductor devices that convert sunlight into direct current (DC) electricity. Groups of PV cells are electrically configured into modules and arrays, which can be used to charge batteries, operate motors, and to power any number of electrical loads.
With the appropriate power conversion equipment, PV systems can produce alternating current (AC) compatible with any conventional appliances, and operate in parallel with and interconnected to the utility grid.
Source: Florida Solar Energy Center
History of the Technology
The photovoltaic effect was discovered by Edmond Becquerel in France in 1839. In 1921, Albert Einstein won the Nobel Prize for his theories explaining the photoelectric effect. However, it was not until 1954 that G.L. Pearson, C.S. Fuller, and D.M. Chapin created an array of several strips of silicon (each about the size of a razor blade), placed them in sunlight, captured the free electrons and turned them into electrical current. This precursor to today's solar PV cells could convert only six percent of the sunlight into useful energy.
In 1963, Sharp Corporation (today the world's largest manufacturer of solar PV modules) succeeded in producing commercially viable silicon-based PV modules. Today, over 90% of all solar PV modules utilize silicon as their base material.
In general, there are three types of silicon-based solar PV cells: mono-crystalline, poly-crystalline and amorphous. Energy conversion efficiencies range from approximately 10% to 22% with each technology capturing and utilizing a different portion of the light spectrum.
Quantum PV's technology is based on Porous Silicon, a material which has not been utilized in the production of solar PV cells up to this point. While R&D efforts are at a relatively early stage, the Quantum Team believes it is theoretically possible to achieve efficiencies on the order of 40% to 60% using this new technology. Computer simulations incorporating Quantum's proposed alterations to the material at the nanometer scale indicate that such efficiencies are indeed possible.
Sources: http://www.solarfuture.org/www.att.com
What makes us unique
The majority of today's solar PV cells are limited to energy conversion efficiencies ranging from 10% to 22%. This means that a solar PV cell, based on the choice of materials used, can convert the energy from a portion of the light spectrum at this rate. Thus, a 22% efficient cell will produce 22 watts of energy for every 100 watts of energy it absorbs from the sun within a limited portion of the light spectrum.
Quantum PV intends to produce what have been referred to by some researchers as ?third-generation? solar PV cells. This involves manipulating the cell material (Porous Silicon) at a much higher degree of precision (the nano-meter level) relative to today's PV manufacturing techniques. Through the use of nano-structures called quantum dots (or quantum wells), a greater portion of the sun's energy can be absorbed and converted into electricity. The end result is improved energy conversion efficiencies estimated to be in the 40% to 60% range.
Quantum PV intends to bring together two disparate fields of research: inquiries relating to the efficiency of Porous Silicon (PSi), and research into the area of nanotechnology and the use of quantum dots. Current research into PSi reveals an understanding of the potential uses of PSi but fails to identify a process by which its efficiency can be raised to develop commercially viable products. By the same token, research into the use of quantum dots reveals an understanding of the potential for high efficiency devices such as solar PV cells and semiconductors, but has not as yet identified a low-cost semiconductor material that could have its band gap manipulated for optimal performance allowing the manufacturer to control the absorptive properties of the solar cell.