Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A better image for plastic solar cells

08.07.2008
EUROCORES’ SONS 2 Programme demonstrates new nanostructure measurements

A new way to help technologists develop efficient and inexpensive plastic electronic devices, such as plastic solar cells and a new type of transistor was showcased by physicist Andrea Liscio, who is supported by the European Science Foundation (ESF) through the EUROCORES programne SONS 2 (Self-Organised NanoStructures), at the EMRS (European Material Research Society) Spring Meeting held in Strasbourg, France at the end of May.

Liscio, a researcher at the Istituto per la Sintesi Organica e la Fotoreattività - Consiglio Nazionale delle Ricerche (CNR) in Bologna, Italy is working in the SUPRAMATES collaborative research project and is using an analytical technique based on a powerful type of microscopy, to analyse materials and map their electrical properties with nanoscopic detail.

Liscio explained how he and his colleagues are using Kelvin Probe Force Microscopy (KPFM), which is an extension of atomic force microscopy, and is 1000 times more powerful than an optical microscope.

He presented details of a systematic study of KPFM measurements of nanostructures. "We studied an extensive range of samples and structures with sizes spanning from several micrometres down to a few nanometres," explained Liscio, "Our results indicated that by operating the KPFM at high frequencies it is possible to visualize different electrical behaviour in nanostructured samples."

A standard AFM has a very sharp probe (just a few atoms across) that scans across a surface the tip bobs up and down following the atomic detail of the surface as forces between the probe and the surface change. The probe's movement is recorded by a highly focused laser linked to a computer. KPFM extends this approach by applying an electric potential to the probe, which allows the electronic properties and composition of the surface to be measured as well as its topography. One property revealed is the work function of the surface, which is linked to a material's catalytic activity, corrosion resistance, and its electronic properties.

"KPFM is a highly versatile tool," explained Liscio, "useful for studying both conducting and semiconducting samples, as well as thin oxide layers, in a non-invasive way."

One group of materials on which the researchers have focused is conjugated nanomaterials. These materials have been widely adopted as the active components of a variety of optoelectronic devices, including organic light-emitting diodes (OLEDs), thin film transistors, solar energy conversion materials.

Optimising such devices depends on being able to fine-tune the movement of electrons at the interface between the electrode and the organic material as well as how they travel through the material. Mapping quantitatively the electronic properties of the surface with a high degree of precision is crucial to this endeavour.

To measure electrostatic interactions, the KPFM probe must be vibrating.
As the probe bobs up and down the force required to keep it oscillating at a steady rate changes measurably, which tells the scientists about the nature of the scanned surface. By using different vibration frequencies, it is possible obtain nanoscale measurements on materials.
Liscio and co-workers and others have shown that vibrating the probe above its natural resonant frequency, they could make the device more sensitive.

Liscio explains that within the frame of SUPRAMATES, the collaborative effort is addressing the question of how nanoscale architecture and function are linked. He and his colleagues have a strong interaction with the research groups of Klaus Müllen (MPIP Mainz) and Alan Rowan (Radboud University Nijmegen), which means they can develop new functional nanostructures for testing in organic electronics.

Within these collaborations, the researchers at the CNR Bologna node have used KPFM to investigate organic semiconductors that can undergo self-assembly on a surface to form sophisticated nanoscopic structures and nanofibres of other organic semiconductors, both of which might one day find application in molecular electronics.

The CNR Bologna team has also applied the technique to studies of organic photovoltaic materials, plastic solar cells in other words, which could significantly cut the costs of renewable solar energy and make it commercially viable. They are testing structurally well-defined plastics known as polyisocyanopeptide polymers as scaffolds on which they can arrange thousands of electron-accepting molecules, among them a group of organic molecules known as the perylene-bis(dicarboximides).

The result is that they can produce hundreds of nanometre-long light-absorbing wires.

They then used KPFM measurements to visualize directly the photovoltaic activity of the nano wires, which offered new insights into how plastic solar cells might be made. Within SUPRAMATES, the performance of devices based on these systems will be explored in the groups of Richard Friend at the University of Cambridge and Franco Cacialli of University College London and the London Center for Nanotechnology.

Thomas Lau | alfa
Further information:
http://www.esf.org
http://www.isof.cnr.it
http://www.esf.org/activities/eurocores/programmes/sons-2.html

More articles from Power and Electrical Engineering:

nachricht Filter may be a match for fracking water
26.09.2017 | Swansea University

nachricht Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent
25.09.2017 | Fraunhofer-Institut für Solare Energiesysteme ISE

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Nerves control the body’s bacterial community

26.09.2017 | Life Sciences

Four elements make 2-D optical platform

26.09.2017 | Physics and Astronomy

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>