By manipulating fundamental physics, researchers can enhance energy-harvesting devices like solar cells
M2020/Shutterstock
Researchers have challenged long-standing principles of physics, paving the way for more efficient energy harvesting technologies, such as solar cells.
Linxiao Zhu from Penn State University has aimed to break Kirchov’s law of thermal radiation for nearly ten years. Established in the 1800s, this law states that the amount of thermal radiation emitted by an object is proportional to the heat it absorbs, linking to the fundamental principles of thermodynamics. Historically, it was believed that these constraints were absolute.
“In standard physics literature, it’s indicated that Kirchov’s law is a fundamental requirement of the second law of thermodynamics. However, this is not entirely accurate,” explains Zhu.
Previous breaches of this law were seen, but only concerning specific wavelengths of radiation. Zhu and his team have achieved a more significant departure from the norm.
This breakthrough required two significant elements: precisely structured materials and magnetic fields. Both the arrangement of the material and the magnetic environment play crucial roles in the behavior of the particles making up the radiation, like photons, and the energy they carry.
The researchers developed thin-layered semiconductors from indium, gallium, and arsenides, meticulously organizing the atoms. They positioned this setup near a strong electromagnet, illuminating it with lights of various colors at distinct temperatures, angles, and magnetic field strengths.
This combination of material structure and ongoing magnetic influence led to a significant disparity between the radiation absorbed and emitted—up to 43% more radiation was released than was originally absorbed. Zhu attributes this phenomenon to the presence of multiple colors of light. This characteristic is particularly beneficial since sunlight comprises a mixture of colors when hitting solar cell devices.
Aaswath Raman from UCLA indicates that this trial is a major advancement toward turning previously theoretical concepts into reality. He remarks that the stark difference between absorbed and emitted radiation is “a significant breakthrough.”
While novel materials can enhance the efficiency of light and heat-absorbing devices, the requirement for magnetic fields presents challenges. However, Raman remains optimistic about the emergence of new materials that display magnetic properties without requiring proximity to magnets, which could resolve these issues through innovative electromagnetic techniques.
Source: www.newscientist.com
