Nothing lasts forever, even something as old as 165 years!
A student research team at Pennsylvania State University has reportedly demonstrated a “dramatic breaking” of the long-standing Kirchhoff’s law of thermal radiation.
According to an article posted on the Penn State website, the team and their academic advisors designed a structure utilizing nonreciprocal emitters that can send emissions in different directions. Their breakthrough directly counters the long-standing premise that materials that absorb electromagnetic radiation at a given wavelength and angle must be equal to their capability to emit at the same wavelength and angle.
Zhenong Zhang, a doctoral candidate in mechanical engineering at Penn State, says that the team’s findings could be used to make the harvesting of solar energy even more efficient. “If we have nonreciprocal emitters,” says Zhang, “we can send emissions toward a different direction. Then, we could place another solar cell there to absorb this part of energy, increasing the overall power conversion efficiency.”
Linxiao Zhu, an assistant professor of mechanical engineering at Penn State, expanded further on the team’s research. “We designed a structure that has five semiconductor layers, each with slightly different compositions…the structure absorbs and emits thermal radiation over multiple wavelengths, so we expect to see the effect over a broad wavelength band.”
The article describing the research of the Penn State student research team is available at https://www.psu.edu/news/engineering/story/rewriting-scientific-law-unlock-potential-energy-sensing-and-more.
The results of the work conducted by the team were published in late June in Physics Magazine (available at https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.135.016901).
