The “black swan theory” refers to real events beyond the realm of normal expectations–and that’s how an international team of researchers at SciTech Solar (lead by a former professor emeritus from Penn State) are referring to their latest breakthrough, a technology that allows for ultra high-efficiency solar cells to generate DC, or direct current electricity.
Why is this such a big deal in the solar world? Apparently because it makes possible the design and fabrication of a new class of solar energy converters which could allow for a dramatic increase in energy conversion efficiency and cost savings of solar cells. According to the company, this is a technology that can successfully compete with today’s semiconductor-based solar cells while exceeding efficiencies and decreasing costs. They’re hailing it as a scalable, sustainable, adaptable and environmentally-friendly technology that will allow manufacturers to quickly and economically shift to new materials if a shortage of any one type occurs.
The technology is based on a new “optical rectification” process that makes use of a simple, cost-effective, single element system that extracts energy from the solar spectrum from the infrared through the visible light spectrum. This broad-spectrum absorption significantly contributes to the gain in efficiency as compared to today’s solar cells, allowing these single element cells to act simultaneously as both a receiving antenna and as a rectifier to absorb and convert solar energy to an electric current. Such a device is historically termed a “rectenna” and was developed for microwave power transmission.
In extensive computer simulations, scientists from United States, Belgium and Korea performed quantum-mechanical calculations that agree with the rectification results of the actual operation of the device, showing rectification of light throughout the visible region and a significant DC current output. The scientists obtained efficiencies comparable to and exceeding those of current solar cell devices (efficiencies as high as 50% were recorded). The scientists are currently developing prototype devices which include more robust antenna structures and plasmonic effects to enhance output and efficiency.