Nav: Home

Exploring the conversion of heat to electricity in single molecules

May 09, 2017

Osaka, Japan -- The direct conversion of a temperature difference into electricity, known as the thermoelectric effect, is an environmentally friendly approach to directly harvesting electricity from heat. The ability of a material to convert heat to electricity is measured by its thermoelectric figure of merit. Materials with a high thermoelectric figure of merit are thus widely desired for use in energy harvesting. Quantum confinement effects in nanomaterials arising from their discrete electronic states may increase their thermoelectric figure of merit. In particular, a single molecule bridging two electrodes displays quantum confinement. Optimization of the electronic states of a single molecule bridging electrodes could yield a large thermoelectric effect. The contact between the molecule and electrodes will also influence its thermoelectric behavior. However, this relationship has seldom been considered because of technical difficulties.

Researchers at Osaka University have recently investigated the influence that the geometry of single molecule-electrode contacts has on the thermoelectric behavior of the molecule. As reported in a recent edition of Scientific Reports, they simultaneously measured the electrical conductance and thermovoltage of molecules with different groups anchoring the molecules to the electrodes at room temperature in vacuum.

The team first fabricated structures consisting of gold electrodes bridged by various single molecules. The distance between the electrodes, which were held under a temperature gradient, was repeatedly increased and decreased while the electrical conductance and thermovoltage of each structure was measured.

"We investigated the thermoelectric characteristics of various single benzene-based molecules with an emphasis on influence of their junction structures," says corresponding author Makusu Tsutsui. "The molecules displayed different behavior depending on their electrode-anchoring groups, and all molecule types displayed multiple thermovoltage states."

The multiple thermovoltage states of the molecules were investigated by thermoelectric measurements and theoretical analysis. The largest thermoelectric effect was observed for structures containing a stretched thiol linkage with the gold electrode. The increased thermovoltage of the structures with a stretched gold-thiol bond was attributed to this configuration shifting the energy level of the molecule involved in electron transport to a more favorable position.

"The observed dependence of thermovoltage on the anchoring group in the junction structures reveals a way to modulate the thermoelectric performance of single-molecule devices," explains Tsutsui.

The group's results expand our understanding of how the geometry of a single-molecule device can influence its thermoelectric figure of merit. These findings should contribute to the development of single-molecule thermoelectric devices that can efficiently derive electricity from heat.
-end-


Osaka University

Related Electricity Articles:

Windows will soon generate electricity, following solar cell breakthrough
Semi-transparent solar cells that can be incorporated into window glass are a 'game-changer' that could transform architecture, urban planning and electricity generation, Australian scientists say in a paper in Nano Energy.
Static electricity as strong as lightening can be saved in a battery
Prof. Dong Sung Kim and his joint research team presented a new technology that can increase the amount of power generated by a triboelectric nanogenerator.
To make amino acids, just add electricity
By finding the right combination of abundantly available starting materials and catalyst, Kyushu University researchers were able to synthesize amino acids with high efficiency through a reaction driven by electricity.
Using renewable electricity for industrial hydrogenation reactions
The University of Pittsburgh's James McKone's research on using renewable electricity for industrial hydrogenation reactions is featured in the Journal of Materials Chemistry A's Emerging Investigators special issue.
Water + air + electricity = hydrogen peroxide
A reactor developed by Rice University engineers produces pure hydrogen peroxide solutions from water, air and energy.
Producing electricity at estuaries using light and osmosis
Researchers at EPFL are working on a technology to exploit osmotic energy -- a source of power that's naturally available at estuaries, where fresh water comes into contact with seawater.
Experimental device generates electricity from the coldness of the universe
A drawback of solar panels is that they require sunlight to generate electricity.
Capturing bacteria that eat and breathe electricity
WSU researchers traveled to Yellowstone National Park to find bacteria that may help solve some of the biggest challenges facing humanity -- environmental pollution and sustainable energy.
Converting Wi-Fi signals to electricity with new 2D materials
Imagine a world where smartphones, laptops, wearables, and other electronics are powered without batteries.
Static electricity could charge our electronics
Static electricity is one of the most common, yet poorly understand, forms of power generation.
More Electricity News and Electricity Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.