Domestic researchers have developed a technology that can dramatically increase the efficiency of converting light energy into electrical or chemical energy. This is expected to accelerate the commercialization of future energy technologies, including next-generation solar cells and eco-friendly hydrogen production technologies.
Professor Park Jung-young of the Korea Advanced Institute of Science and Technology (KAIST), along with Professor Lee Moon-sang of Inha University, announced on the 12th that they have developed a technology that extends the lifetime of 'hot holes' necessary for converting light energy into other forms of energy and amplifies their flow. The research findings were published online in the journal 'Science Advances' on the 7th.
'Plasmonic hot carriers,' which are instantaneously generated when light hits a metallic nanostructure, are important mediators that convert light energy into high-value energy sources such as electricity and chemical energy. Among them, hot holes are crucial when converting light into electrical or chemical energy, but they were challenging to apply since they dissipate within a short time of ㎰ (picoseconds, one trillionth of a second).
The research team created a 'nano diode structure' by placing a metal nanonet on a substrate made of a special semiconductor material (p-type gallium nitride) to facilitate the extraction of hot holes from the substrate surface. They successfully amplified the flow of hot holes by about two times.
They also utilized a photoconductive atomic force microscope (pc-AFM) to analyze the flow of hot holes in real-time at the level of ㎚ (nanometers, one billionth of a meter). The researchers found that the flow of hot holes is strongly activated at 'hot spots' where light is locally concentrated on the gold nanonet, but changing the growth direction of the gallium nitride substrate also activates the flow of hot holes in areas outside the hot spots.
The researchers stated, "We have found an efficient method for converting light into electrical and chemical energy, and utilizing this is expected to greatly advance technologies such as next-generation solar cells, photocatalysis, and hydrogen production."
Professor Park Jung-young remarked, "We were able to control the flow of hot holes for the first time using the nano diode technique, and this could make innovative contributions to various optoelectronic devices and photocatalytic applications" and added, "For example, it can be applied to energy conversion technologies utilizing solar power (solar cells, hydrogen production, etc.) or the development of ultra-small optoelectronic devices (light sensors, nano semiconductor devices)."
References
Science Advances (2025), DOI: https://doi.org/10.1126/sciadv.adu0086