Nav: Home

Golden sandwich could make the world more sustainable

September 09, 2018

Scientists have developed a photoelectrode that can harvest 85 percent of visible light in a 30 nanometers-thin semiconductor layer between gold layers, converting light energy 11 times more efficiently than previous methods.

In the pursuit of realizing a sustainable society, there is an ever-increasing demand to develop revolutionary solar cells or artificial photosynthesis systems that utilize visible light energy from the sun while using as few materials as possible.

The research team, led by Professor Hiroaki Misawa of the Research Institute for Electronic Science at Hokkaido University, has been aiming to develop a photoelectrode that can harvest visible light across a wide spectral range by using gold nanoparticles loaded on a semiconductor. But merely applying a layer of gold nanoparticles did not lead to a sufficient amount of light absorption, because they took in light with only a narrow spectral range.

In the study published in Nature Nanotechnology, the research team sandwiched a semiconductor, a 30-nanometer titanium dioxide thin-film, between a 100-nanometer gold film and gold nanoparticles to enhance light absorption. When the system is irradiated by light from the gold nanoparticle side, the gold film worked as a mirror, trapping the light in a cavity between two gold layers and helping the nanoparticles absorb more light.

To their surprise, more than 85 percent of all visible light was harvested by the photoelectrode, which was far more efficient than previous methods. Gold nanoparticles are known to exhibit a phenomenon called localized plasmon resonance which absorbs a certain wavelength of light. "Our photoelectrode successfully created a new condition in which plasmon and visible light trapped in the titanium oxide layer strongly interact, allowing light with a broad range of wavelengths to be absorbed by gold nanoparticles," says Hiroaki Misawa.

When gold nanoparticles absorb light, the additional energy triggers electron excitation in the gold, which transfers electrons to the semiconductor. "The light energy conversion efficiency is 11 times higher than those without light-trapping functions," Misawa explained. The boosted efficiency also led to an enhanced water splitting: the electrons reduced hydrogen ions to hydrogen, while the remaining electron holes oxidized water to produce oxygen -- a promising process to yield clean energy.

"Using very small amounts of material, this photoelectrode enables an efficient conversion of sunlight into renewable energy, further contributing to the realization of a sustainable society," the researchers concluded.
-end-


Hokkaido University

Related Semiconductor Articles:

Paving a way to achieve unexplored semiconductor nanostructures
A research team of Ehime University paved a way to achieve unexplored III-V semiconductor nanostructures.
Researchers repurpose failed cancer drug into printable semiconductor
Many potential pharmaceuticals end up failing during clinical trials, but thanks to new research from the University of Illinois, biological molecules once considered for cancer treatment are now being repurposed as organic semiconductors for use in chemical sensors and transistors.
Clarification of a new synthesis mechanism of semiconductor atomic sheet
Researchers at Tohoku University in Japan succeeded in clarifying a new synthesis mechanism regarding transition metal dichalcogenides (TMD), which are semiconductor atomic sheets having thickness in atomic order.
Future of portable electronics -- Novel organic semiconductor with exciting properties
Organic semiconductors have advantages over inorganic semiconductors in several areas.
A new method for quantifying crystal semiconductor efficiency
Japanese scientists have found a new way to successfully detect the efficiency of crystal semiconductors.
X-rays reveal monolayer phase in organic semiconductor
An international team of researchers has investigated how the electrical properties of dihexyl-quarterthiophene thin films depend on their structure.
Atomic 'patchwork' using heteroepitaxy for next generation semiconductor devices
Researchers from Tokyo Metropolitan University have grown atomically thin crystalline layers of transition metal dichalcogenides (TMDCs) with varying composition over space, continuously feeding in different types of TMDC to a growth chamber to tailor changes in properties.
Tuning into the LCDs of tomorrow: Exploring the novel IGZO-11 semiconductor
Indium-gallium-zinc oxide ceramics are used as the backplane for flat-panel displays, this was made possible through substantial synergistic contributions coming from the powerhouse that is Japan.
Probing semiconductor crystals with a sphere of light
Tohoku University researchers have developed a technique using a hollow sphere to measure the electronic and optical properties of large semiconducting crystals.
Organic electronics: a new semiconductor in the carbon-nitride family
Teams from Humboldt-Universit├Ąt and the Helmholtz-Zentrum Berlin have explored a new material in the carbon-nitride family.
More Semiconductor News and Semiconductor Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.