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Welcome to the SDGs in the NEWS Podcast.
This is Susan Yoshimura, Managing Editor of Japan 2 Earth, coming to you from Tokyo.
Today, we bring you another English article on Japan and the SDGs.
You can find the full text on our website. Just click the link in the episode notes.
Have a listen.
The answer to eco-friendly semiconductors lies in your coffee.
Japanese researchers have discovered that a coffee compound boosts the conductivity
of organic semiconductors. Could it be time for Japan to make a comeback?
Japan's semiconductor industry was once the driving force of Japan's economy.
Now, it lags behind the United States and China. However, for the first time in the world,
a research team from the National Institute of Advanced Industrial Science and Technology
AASD, has successfully boosted the performance of organic semiconductors 100-fold. They did this
by applying caffeic acid, a substance which is naturally found in coffee, to the electrodes.
Because the technology uses compounds derived from biomass, it reduces the environmental impact.
It could also play a key role in lifting Japan out of its current predicament.
Until the 2000s, Japan was a global leader in the semiconductor industry.
The chips were called the rice of manufacturing for their crucial role in the domestic manufacturing
industry. However, Japan lost its global competitive edge due to failures in its
development investment strategy and the emergence of the United States, China, and Taiwan.
There are now no traces of its past glory.
To that end, the government put together a semiconductor strategy in June 2021.
It also began investing in massive subsidies to attract R&D and production bases. In an attempt
to turn the tables, Japan has also agreed with the U.S. to establish R&D centers for next-generation
semiconductors.
Semiconductors are indispensable for all kinds of electronic devices, including computers,
telecommunication devices, automobiles, and household appliances. From the standpoint of
economic security, Japan needs to boost research and development, and production capabilities.
There have been several game-changers in the semiconductor industry, from simple memory
devices like DRAMs to system LSIs, which combine multiple integrated circuits for efficient,
advanced functions. Now, it looks like organic semiconductors will take center stage.
While large equipment is necessary to make inorganic semiconductors,
organic semiconductors are manufactured by applying a substance to a substrate.
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Additionally, their flexibility, which allows them to bend, means they have the potential for
a wide range of applications. In fact, they are already being used in organic electroluminescent
displays, OELD, and foldable smartphones. But they also have a disadvantage. In semiconductors,
components acting as electrical conductors are sandwiched between electrodes. Their performance
is as good as the quantity of electricity they can conduct, and organic semiconductors are
limited in this respect. Increasing their conductivity is a major issue to solve for
their wider application. Therefore, the research team hypothesized that adding a layer of a
substance that would increase conductivity between the electrode and semiconductor material layers
would boost the chip's performance. Kuki Akike, the head researcher at AIST, leads the research
team. He decided to use a substance extracted from biomass, a plant-based and organic resource,
for the layer. By doing so, he hoped to contribute to the SDGs, which he calls a
common challenge across the planet. Semiconductors, which are used in large
quantities in all kinds of electronic devices, do not easily decompose. That means they become a
significant environmental burden when discarded. However, biomass-derived semiconductors can
easily decompose, thus reducing the environmental burden and making them suitable for a recycling
oriented society. To improve conductivity, it is imperative to choose a substance whose molecular
structure clearly separates its positive and negative electric charges. The team discovered
that a group of compounds called phenylpropanoids was the best candidate among biomass-derived
substances. They decided to test caffeic acid, a type of polyphenol found in coffee,
which has antioxidant properties. Not only does it have a clear intramolecular charge distribution,
but it is also easy to obtain at a low cost. The researchers sprayed caffeic acid onto an
electrode to create a layer between the organic semiconductor and the electrode.
When they checked its conductivity, they realized that it had increased 100-fold.
One end of the caffeic acid molecule has a catechol group structure, which easily bonds
with electrodes. When the molecules are sprayed onto an electrode, they align in the same
direction within the layer, which boosts conductivity. This is reportedly the first
time an eco-friendly, biomass-derived substance was used to pass electricity efficiently through
an organic semiconductor. The team aims to continue improving organic semiconductors by
increasing their conductivity through further research. If technology from Japan produces
efficient, eco-friendly organic semiconductors, it could provide a much-needed breakthrough for
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Japan's semiconductor industry. Akaike says, we aim to minimize the impact of discarded
semiconductors on the environment as much as possible. Going forward, we hope to create
an organic semiconductor entirely with biomass-derived substances, and not just the layer on top of the electrodes.
That brings us to the end of today's article. If you enjoyed this story, do let us know,
and check out our website by clicking on the link in the episode notes. You can follow us
on Twitter for our latest news. And don't forget to subscribe so you never miss an episode.
Until next time, this is Susan Yoshimura of Japan to Earth, signing off.
