By Maeva Chabrier,
Japanese and Swiss scientists have created glass that generates an electric current when exposed to light, an innovation they hope could lead to the production of clean energy in the long term.
The researchers at the Tokyo Institute of Technology and the Swiss Federal Institute of Technology Lausanne confirmed the generation of a current on the glass after they etched a circuit into its surface with a femtosecond laser, which emits ultrashort pulses of light.
Their discovery was reported on the website of the U.S. science magazine Physical Review Applied in January.
Yves Bellouard, an associate professor at the Swiss school and director of its Galatea Lab, told Kyodo News that the technology is "surprising and innovative" as it can transform a material without adding anything.
According to the expert on laser technologies, a student in his laboratory named Goezden Torun had prior experience using a femtosecond laser on different types of glass, including tellurite glass, an industrial substance used to make optical fibers. The collaborative project involved using tellurite glass prepared by the Japanese institute.
During the research, Torun, who earlier studied at Japan's Tohoku University, created a semiconductor crystal on the glass by accident. With a laser-inscribed circuit on its surface, the tellurite glass generated an electric current in reaction to ultraviolet and visible light, the researchers said.
"We didn't expect to see that kind of phenomenon by using lasers," said Tetsuo Kishi, an associate professor at the institute.
"The glass is a passive material which just lets the light through, but after using a femtosecond laser, the glass changes to an active material which can transmit electrical current like a semiconductor," Kishi said.
"We could change the shape of the glass and make it lighter and thinner by altering the composition so that it will be more useful and practical," Kishi added.
Although challenges remain, the researchers hope the day will come when windows partially covered by tellurite glass transformed by femtosecond lasers may be developed.
"This would be a source of clean energy and reduce the need for fossil fuels," Bellouard said.
