Welcome to the Nickel Research Group on Organic Electronics and Lipid Membranes
We are interested in the physics of ordered molecular materials. Depending on the detailed shape of a molecule, various phases are observed which have no direct analogue for pure elements; a prominent example are liquid crystalline and lyotropic phases, which provide the structural concept of cell membranes. If the molecules allow for even closer packing, solid crystalline phases, so called van der Waals crystals, are observed, which share all crystallographic characteristics of inorganic materials. If such molecules exhibit also delocalized electrons, which is the case for conjugated and aromatic molecules, the rich field of organic electronics opens.
In the Nickel group, we build up thin film structures composed of small molecules. For organic electronics applications, aromatic and conjugated molecules such as C60 or pentacene are deposited from vacuum to build field-effect-transistors, solar cells, and biosensors. In order to reconstitute cell membranes on chip surfaces, we use natures own building blocks, lipids, which are deposited from solution via self assembly. Our goal is to understand the physical mechanisms which govern such systems. For this purpose we relate functional properties such as transistor I-V transfer curves to microscopic properties obtained from structural and optical characterization techniques. In particular, we employ brilliant x-rays and neutrons as complementary probes to unravel molecular arrangements at the nm scale.
Our research work on imaging structural phases in organic semiconductors was published in Nature Communications in June 2014. See also LMU press release "Organic semiconductors: Nano-imaging probes molecular disorder" for the full story.
Sub-micron phase coexistence in small-molecule organic thin films revealed by infrared nano-imaging
Christian Westermeier, Adrian Cernescu, Sergiu Amarie, Clemens Liewald, Fritz Keilmann, Bert Nickel
Nature Communications 5, Article Number 4101, doi: 10.1038/ncomms5101 (2014) get article
Our novel technique to image defects in organic semiconductors was selected as the cover article of the Advanced Materials issue 40 in October 2013. Many thanks to Chriss Hohmann (NIM) who designed the motive. See also LMU-news for the full story.
Thin Films: Mapping of Trap Densities and Hotspots in Pentacene Thin-Film Transistors by Frequency-Resolved Scanning Photoresponse Microscopy
Christian Westermeier, Matthias Fiebig and Bert Nickel
Advanced Materials 25 (40) p. 5677 (2013) get article
In recognition for his work, Christian Westermeier was awarded the Best Poster Prize of the symposia at the E-MRS meeting 2012 (Strasbourg) and the MRS meeting 2013 (Boston). Our article was granted the Publication Award 2013 of the Center for NanoScience (CeNS).
Our research on ambipolar transistors made it to the cover of the Advanced Materials issue 15 of April (2013). Many thanks to Chriss Hohmann (NIM) who designed the motive. See also NIM-news for the full story.
Thin Film Transistors: Dual Channel Operation Upon n-Channel Percolation in a Pentacene-C60 Ambipolar Organic Thin Film Transistor
Simon J. Noever, Stefan Fischer and Bert Nickel
Advanced Materials 25 (15) p 2105 (2013) get article
At the E-MRS spring meeting in May 2013, Simon Noever was awarded the Best Poster Prize in recognition for his results.