As the push for tinier and faster electronics continues, a new finding by University of British Columbia scientists could help inform the design of the next generation of cheaper, more efficient devices.
The work, published this week in Nature Communications, details how electronic properties at the edges of organic molecular systems differ from the rest of the material.
Organic materials--plastics--are of great interest for use in solar panels, light emitting diodes and transistors. They're low-cost, light, and take less energy to produce than silicon. Interfaces--where one type of material meets another--play a key role in the functionality of all these devices.
"We found that the polarization-induced energy level shifts from the edge of these materials to the interior are significant, and can't be neglected when designing components," says UBC PhD researcher Katherine Cochrane, lead author of the paper.
'While we were expecting some differences, we were surprised by the size of the effect and that it occurred on the scale of a single molecule," adds UBC researcher Sarah Burke, an expert on nanoscale electronic and optoelectronic materials and author on the paper.
The researchers looked at 'nano-islands' of clustered organic molecules. The molecules were deposited on a silver crystal coated with an ultra-thin layer of salt only two atoms deep. The salt is an insulator and prevents electrons in the organic molecules from interacting with those in the silver--the researchers wanted to isolate the interactions of the molecules.
Not only did the molecules at the edge of the nano-islands have very different properties than in the middle, the variation in properties depended on the position and orientation of other molecules nearby.
The researchers, part of UBC's Quantum Matter Institute, used a simple, analytical model to explain the differences which can be extended to predict interface properties in much more complex systems, like those encountered in a real device.
"Herbert Kroemer said in his Nobel Lecture that 'The interface is the device' and it's equally true for organic materials," says Burke. "The differences we've seen at the edges of molecular clusters highlights one effect that we'll need to consider as we design new materials for these devices, but likely they are many more surprises waiting to be discovered."
Cochrane and colleagues plan to keep looking at what happens at interfaces in these materials and to work with materials chemists to guide the design rules for the structure and electronic properties of future devices.
The experiment was performed at UBC's state-of-the-art Laboratory for Atomic Imaging Research, which features three specially designed ultra-quiet rooms that allow the instruments to sit in complete silence, totally still, to perform their delicate measurements. This allowed the researchers to take dense data sets with a tool called a scanning tunnelling microscope (STM) that showed them the energy levels in real-space on the scale of single atoms.
Chris Balma | EurekAlert!
A new tool for discovering nanoporous materials
23.05.2017 | Ecole Polytechnique Fédérale de Lausanne
Did you know that packaging is becoming intelligent through flash systems?
23.05.2017 | Heraeus Noblelight GmbH
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy