Tag Archives: organic materials

Bendable phones that are partially organic

It’s been about nine  or 10 years since I first heard about bendable phones (my September 29, 2010 posting). The concept keeps popping up from time to time (my April 25, 2017 posting) and this time, we have Australian scientists to thank for this latest work described in an October 5, 2018 news item on Nanowerk (Note: A link has been removed),

Engineers at ANU [Australian National University] have invented a semiconductor with organic and inorganic materials that can convert electricity into light very efficiently, and it is thin and flexible enough to help make devices such as mobile phones bendable (Advanced Materials, “Efficient and Layer-Dependent Exciton Pumping across Atomically Thin Organic–Inorganic Type-I Heterostructures”).

The invention also opens the door to a new generation of high-performance electronic devices made with organic materials that will be biodegradable or that can be easily recycled, promising to help substantially reduce e-waste.

An October 5, 2018 ANU press release (also on EurekAlert but published October 4, 2018) expands on the theme,

The huge volumes of e-waste generated by discarded electronic devices around the world is causing irreversible damage to the environment. Australia produces 200,000 tonnes of e-waste every year – only four per cent of this waste is recycled.

The organic component has the thickness of just one atom – made from just carbon and hydrogen – and forms part of the semiconductor that the ANU team developed. The inorganic component has the thickness of around two atoms. The hybrid structure can convert electricity into light efficiently for displays on mobile phones, televisions and other electronic devices.

Lead senior researcher Associate Professor Larry Lu said the invention was a major breakthrough in the field.

“For the first time, we have developed an ultra-thin electronics component with excellent semiconducting properties that is an organic-inorganic hybrid structure and thin and flexible enough for future technologies, such as bendable mobile phones and display screens,” said Associate Professor Lu from the ANU Research School of Engineering.

PhD researcher Ankur Sharma, who recently won the ANU 3-Minute Thesis competition, said experiments demonstrated the performance of their semiconductor would be much more efficient than conventional semiconductors made with inorganic materials such as silicon.

“We have the potential with this semiconductor to make mobile phones as powerful as today’s supercomputers,” said Mr Sharma from the ANU Research School of Engineering.

“The light emission from our semiconducting structure is very sharp, so it can be used for high-resolution displays and, since the materials are ultra-thin, they have the flexibility to be made into bendable screens and mobile phones in the near future.”

The team grew the organic semiconductor component molecule by molecule, in a similar way to 3D printing. The process is called chemical vapour deposition.

“We characterised the opto-electronic and electrical properties of our invention to confirm the tremendous potential of it to be used as a future semiconductor component,” Associate Professor Lu said.

“We are working on growing our semiconductor component on a large scale, so it can be commercialised in collaboration with prospective industry partners.”

Here’s a link to and a citation for the paper,

Efficient and Layer‐Dependent Exciton Pumping across Atomically Thin Organic–Inorganic Type‐I Heterostructures by Linglong Zhang, Ankur Sharma, Yi Zhu, Yuhan Zhang, Bowen Wang, Miheng Dong, Hieu T. Nguyen, Zhu Wang, Bo Wen, Yujie Cao, Boqing Liu, Xueqian Sun, Jiong Yang, Ziyuan Li. Advanced Materials Volume30, Issue 40 1803986 (October 4, 2018) DOI:https://doi.org/10.1002/adma.201803986 First published [onliine]: 30 August 2018

This paper is behind a paywall.

Interfaces are the device—organic semiconductors and their edges

Researchers at the University of British Columbia (UBC; Canada) have announced a startling revelation according to an Oct. 6, 2015 news item on ScienceDaily,

As the push for thinner 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.

An Oct. 6, 2015 UBC news release on EurekAlert, which originated the news item, expands on the theme,

Organic [as in carbon-based] 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. [emphasis mine] “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.

Here’s a link to and a citation for the paper,

Pronounced polarization-induced energy level shifts at boundaries of organic semiconductor nanostructures by K. A. Cochrane, A. Schiffrin, T. S. Roussy, M. Capsoni, & S. A. Burke. Nature Communications 6, Article number: 8312 doi:10.1038/ncomms9312 Published 06 October 2015

This paper is open access. Yes, I borrowed from Nobel Laureate, Herbert Kroemer for the headline. As Woody Guthrie (legendary American folksinger) once said, more or less, “Only steal from the best.”