Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Exploring the conversion of heat to electricity in single molecules

11.05.2017

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.


This is a schematic model of a single-molecule device. A molecule is interconnected to hot and cold electrodes via chemical bonds.

Credit: Osaka University

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.

Saori Obayashi | EurekAlert!

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Structured light and nanomaterials open new ways to tailor light at the nanoscale

23.04.2018 | Physics and Astronomy

On the shape of the 'petal' for the dissipation curve

23.04.2018 | Physics and Astronomy

Clean and Efficient – Fraunhofer ISE Presents Hydrogen Technologies at the HANNOVER MESSE 2018

23.04.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>