Researchers develop near-zero epsilon material controllable by thermal radiation and capable of withstanding extreme environments

Thermal radiation is electromagnetic radiation emitted by all objects having a temperature and, more representatively, there is the spectrum of solar radiation that penetrates the Earth and causes the greenhouse effect.

Control and energy utilization of thermal radiation emitted by solar energy, thermal power generation and waste heat in industrial sites can reduce the cost of electricity generation. Therefore, interest in radiation spectrum control technology is increasing in areas such as cooling, heat dissipation and power generation.

Until now, radiation spectrum control technology has mainly been used in general environmental conditions, but recently, materials capable of withstanding extreme environments such as space, aviation and TPV systems have become required.

A team led by lead researcher Jongbum Kim of the Nanophotonics Research Center has developed a refractory material to control the spectrum of thermal radiation that retains its optical properties even at high temperatures of 1,000°C in atmospheric atmosphere and strong illumination ultraviolet. The study is published in Advanced science.

The team fabricated lanthanum-doped barium stannate oxide (“LBSO”) as a nanoscale thin film without lattice constraints by pulsed laser deposition. Unlike conventional refractory conductive materials such as tungsten, nickel and titanium nitride, which are easily oxidized at high temperatures, LBSO material maintains its performance even when exposed to high temperatures of 1000°C and to intense ultraviolet light of 9 MW/cm.².

The researchers then fabricated a thermal emitter based on a multilayer structure with high spectral selectivity in the infrared band using LBSO, and found that the multilayer structure was stable to heat and light as with the single-layer thin film, thus confirming its applicability to TPV power generation. technology. The LBSO material allows thermal radiation to be transferred to the photovoltaic cell without any additional method to prevent it from oxidizing in contact with air.

“As an alternative to solar and wind renewable energy, whose electricity production varies depending on weather conditions, environmentally friendly thermoelectric power generation technology that uses radiant energy emitted by the sun and high-temperature environments for generating electricity are attracting more and more attention,” KIST said. lead researcher Jongbum Kim. “LBSO will help combat climate change and the energy crisis by accelerating the commercialization of thermoelectric power generation.”

Researchers expect that LBSO can be applied not only to thermoelectric power generation technology and waste heat recycling of industrial equipment, but also to heat management technology generated by exposure and absorption of strong sunlight in extreme environments such as space and aviation, as it is highly resistant to UV exposure.