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Solar Cells, Reborn through Nano Design?

  • 조회. 578
  • 등록일. 2017.02.27
  • 작성자. Administrator

Solar Cells, Reborn through Nano Design?

-Special Interview with Professor Chang-Hee Cho and Senior Researcher Seong Ho Baek


DGIST, there are many opportunities to exchange research content. Once a year,

Convergence Research Festivals are held, and on the second and fourth Tuesdays

of each month, small-scale seminars are also held. At the festival, Professor Chang-Hee

Cho suggested an idea that I had not thought about, and that became the

starting point of my convergence research."


Researcher, Seong Ho Baek from the DGIST Smart Textile Convergence Research

Group recalled three years ago when he first discussed his research topic with

Professor Chang-Hee Cho from the Department of Emerging Materials Science.

Professor Cho started talking about the research to Baek who had been

researching solar cells that convert solar light energy into electric energy by

saying, "Why don"t we try to do the basic research together to make a semiconductor,

which is a basic element of solar cells, absorb solar light well?"



Nanoscience to Semiconductors



photoelectric conversion efficiency of solar cells is good" means they absorb

more light and convert it to electric energy as efficiently as possible. The

ability to absorb light at this time is called "light absorption efficiency".

It depends on the light absorbing ability of the semiconductor, which is the

basic element of the solar cells. Professor Cho said that, "I thought the

nanotechnology field that I was researching was the key to overcoming the

limitations of solar cells that senior researcher Baek was researching at that

time." The idea was to increase the light absorption efficiency by forming

a nanomaterial with a specific pattern on the existing semiconductor surface.

He then explained, "Since then, we have been meeting more than once a week

and developing our research."



years after the research, the two succeeded in increasing the light absorption

efficiency by designing nanostructures in semiconductors for the first time and

published the results as a cover paper in the April 2016 issue of "

. Professor Cho said, “Semiconductors that absorb light well at

specific wavelengths can absorb light at high efficiency at wide wavelengths in

the visible light range.”



Cho and senior researcher Baek have formed nanostructures with wave-like

periodicity on the surface of a cylindrical structure on a semiconductor

surface. As a result, a resonance phenomenon was caused by the reaction with

the light within a wide wavelength and the absorption rate increased by the

light of the visible light range staying longer on the semiconductor. In the

course of the research, the two thought that nanodesign semiconductors that

absorb more light could be applied to high performance optical sensor

technology in addition to solar cells. Professor Cho then added, "Light

sensors can convert light into electrical signals, so by adjusting the design

of the nanostructure, the sensitivity of the sensor can be improved."


Now in

its fourth year, their encounter is not over yet. Professor Cho said, "In

recent years, senior researcher Baek has helped other research teams by

suggesting applications of our nano semiconductor design technology to photo-electrochemical




is a growing interest in research on clean renewable energy sources. Among

them, hydrogen is considered a clean energy source. When separating water into

hydrogen and oxygen, light acts as a catalyst. Things that play such roles are

called the photoelectric chemical devices. In fact, the light absorbed by this

device helps catalysis. Professor Cho and senior researcher Baek have designed

a photoelectric chemical device in the form of a disk, which has been used in

thin film form, and has increased light absorption by causing resonance with

light at a specific wavelength. Professor Cho said, "A paper on photo-electrochemical

devices was published in the journal "
Energy and Environmental Science"

in June 2016. With the research with senior researcher Baek, I have written

three papers and applied for two patents so far."



the two are working on their next study on the topic of solar cells. When light

absorbed by semiconductors is converted into electrical signals, metal is

needed. It is their goal to increase the conversion efficiency of electrical

signals by applying nanodesign to these metals.



X Chemistry Exploded


convergence research between the two, which has continued for three years, has

become a representative model for win-win cooperation research between research

institutes and colleges at DGIST. Senior researcher Seong Ho Baek said, “Since

I started my research voluntarily rather than at the request of an institution

or society, I was able to succeed through continuous communication.” Professor

Cho then added, “There is often a chemical reaction that occurs between people.

With people whom you lack chemistry, it is difficult to get along no matter how

hard you try. Fortunately, the more we conduct research, the better our

chemistry works."

Original version of this

article appears on the Donga Science
By: Lee Gyu Chul

Translation: International Affairs Team