Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Department Seminar
Host: T. Kumagai

Monday, February 13, 2017, 11:00 am
Willstätter House, Faradayweg 10
Dr. Tomoko K. Shimizu
Nanomechanics Group, Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, Tsukuba
Submolecular AFM Imaging and Spectroscopy on Single Molecules Using KolibriSensor and Cantilevers
Submolecular imaging using frequency-modulation (FM) atomic force microscopy (AFM) has recently been established as a stunning technique to reveal the chemical structure of unknown molecules, to characterize intra-molecular charge distributions, and to observe chemical transformations. So far, most of these feats were achieved on planar molecules using the so-called qPlus sensor, a specially designed quartz AFM sensor. The KolibriSensor, another type of quartz AFM sensor, is also expected to be capable of high-resolution imaging, but only very few experimental results have been reported to date.
Here, I present submolecular resolution images and spectroscopic data on single molecules of a porphycene derivative [1] using small oscillation amplitudes with KolibriSensors. I will discuss force volume data and possible imaging mechanism of two isomers of porphycene molecules. We also report a novel imaging method to achieve submolecular resolution on three-dimensional molecules and structures using a silicon (Si) cantilever-based AFM operated with large oscillation amplitudes. At variance with previous implementations, this method allowed us to simultaneously image both intra-molecular structures and the atomic arrangement of the substrate [2]. Force volume measurements over C60 molecules clarified the validity of our method to achieve submolecular resolution [2].
[1] K. Oohora, A. Ogawa, T. Fukuda, A. Onoda, J. Hasegawa, T. Hayashi, Angew. Chem. Int. Ed. 54, 6227 (2015).
[2] C. Moreno, O. Stetsovych, T. K. Shimizu, O. Custance, Nano Lett. 15, 2257 (2015).