Nav: Home

Hand-knitted molecules

January 18, 2019

The fabrication of electronic components usually follows a top-down pathway in specialized physical laboratories. Using special carving tools in clean rooms, scientists are capable of fabricating structures reaching only a few nanometers. However, atomic precision remains very challenging and usually requires special microscopes such as an Atomic Force Microscope (AFM) or a Scanning Tunneling Microscope (STM). Chemists on the other hand routinely achieve a tour de force: They can synthesize large numbers of molecules that are all exactly identical. But synthesizing a single molecule with atomic precision and monitoring this assembly process remains a formidable challenge.

A research team from Empa, the University of Basel and the University of Oviedo has now succeeded in doing just that: The researchers synthesized chain-shaped molecules between two microscopically small gold tips. Each molecule is created individually. The properties of the resulting molecule can be monitored and documented in real time during synthesis.

Micro-manufactory between gold tips

Anton Vladyka, Jan Overbeck and Mickael Perrin work at Empa's "Transport at Nanoscale Interfaces" laboratory, headed by Michel Calame. For their experiments, they used a technique called mechanically controllable break junction (MCBJ). A gold bridge only a few nanometers thin is slowly stretched in a reagent solution until it breaks. Individual molecules can attach themselves to the fracture tips of the nano-bridge and undergo chemical reactions.

Empa researchers dipped the gold tips in a solution of 1,4-diisocyanobenzene (DICB), a molecule with strong electrical dipoles at both ends. These highly charged ends readily bond with gold atoms. The result: When the bridge is torn apart, a DICB molecule detaches individual gold atoms from the contact and thus builds a molecular chain. Each DICB molecule is followed by a gold atom, followed by another DICB molecule, a gold atom, and so on.

High success rate

What is remarkable: the molecular assembly was not dependent on any coincidences, but worked highly reproducible - even at room temperature. The researchers repeatedly opened and closed the gold bridge to better understand the process. In 99 out of 100 trials identical molecular chains of gold and DICB were formed. By monitoring the electrical conductivity between the gold contacts the researchers were even able to determine the length of the chain. Up to three chain links can be detected. If four or more chain links are formed, the conductivity is too low and the molecule remains invisible during this experiment.

Basis for chemical and physical analyses

This new method allows researchers to produce electrically conductive molecules as unique specimens and to characterize them using a variety of methods. This opens up completely new possibilities to change the electrical properties of individual molecules directly ("in situ") and to adjust them with atomic precision. This is considered a crucial step towards the further miniaturization of electronic components. At the same time, it offers deep insights into transport processes at the atomic level. "In order to discover new properties in molecular assemblies, we must first be able to build these molecular structures in a reproducible manner," says Michel Calame. "This is exactly what we have now achieved."
-end-


Swiss Federal Laboratories for Materials Science and Technology (EMPA)

Related Molecules Articles:

Water molecules are gold for nanocatalysis
Nanocatalysts made of gold nanoparticles dispersed on metal oxides are very promising for the industrial, selective oxidation of compounds, including alcohols, into valuable chemicals.
Water molecules dance in three
An international team of scientists has been able to shed new light on the properties of water at the molecular level.
How molecules self-assemble into superstructures
Most technical functional units are built bit by bit according to a well-designed construction plan.
Breaking down stubborn molecules
Seawater is more than just saltwater. The ocean is a veritable soup of chemicals.
Shaping the rings of molecules
Canadian chemists discover a natural process to control the shape of 'macrocycles,' molecules of large rings of atoms, for use in pharmaceuticals and electronics.
The mysterious movement of water molecules
Water is all around us and essential for life. Nevertheless, research into its behaviour at the atomic level -- above all how it interacts with surfaces -- is thin on the ground.
Spectroscopy: A fine sense for molecules
Scientists at the Laboratory for Attosecond Physics have developed a unique laser technology for the analysis of the molecular composition of biological samples.
Looking at the good vibes of molecules
Label-free dynamic detection of biomolecules is a major challenge in live-cell microscopy.
Colliding molecules and antiparticles
A study by Marcos Barp and Felipe Arretche from Brazil published in EPJ D shows a model of the interaction between positrons and simple molecules that is in good agreement with experimental results.
Discovery of periodic tables for molecules
Scientists at Tokyo Institute of Technology (Tokyo Tech) develop tables similar to the periodic table of elements but for molecules.
More Molecules News and Molecules 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

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.