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My name is Tim Cornelissen and I am a PhD student in the Complex Materials and Devices group of Martijn Kemerink. I have obtained my Bachelor and Master’s degree at the department of Applied Physics at Eindhoven University of Technology in the Netherlands. For my Master thesis I worked on the all-optical switching of ferromagnetic thin films, using ultrashort (fs) laser pulses [1].

At Linköping University, I have shifted from inorganic ferromagnets to organic ferroelectrics. Together with my colleague Indre Urbanaviciute, we try to characterize and understand the behavior of a variety of organic ferroelectric materials.

These materials all have a similar structure and form columnar liquid crystals, as shown in Figure 1 for one of our simplest materials: BTA. They have a core that facilitates π-stacking, three dipolar amide groups, and long tails that improve solubility. The dipolar amide groups will order in a head-to-tail fashion, giving rise to a switchable macrodipole [2]. We have shown that this BTA is truly ferroelectric [3], but there are still some properties left to be investigated. We do this both with experiments as well as modelling, such as the Ising model that is shown in Figure 2.

Figure 1: BTA, which forms a columnar liquid crystal with a switchable macro dipole. [2]
Figure 2: A small simulation box of the Ising model, showing 9 columns of BTA with either up (black) or downwards (green) oriented microdipoles.

 

In collaboration with organic chemists we can synthesize and measure and endless amount of possible materials based on the same core-dipole-tail principle. A very exciting possibility is the introduction of a semiconducting core, creating a semiconducting ferroelectric. One of our current projects is to investigate the coupling between the ferroelectric and semiconducting properties in these materials. We have for example shown that is possible to get a switchable injection barrier [4].

There is wide variety of possible applications for these ferroelectrics, such as thin-film transistors, sensors, ferroelectric memories and solar cells. Compared to inorganic electronics, organics have the advantage of easy processing, mechanical flexibility and the absence of toxic or rare elements. And with the power of organic chemistry the possibilities to tune the material properties are endless.

 

 [1] Cornelissen, T. D., Córdoba, R., & Koopmans, B. (2016). Microscopic model for all optical switching in ferromagnets. Applied Physics Letters, 108(14), 142405. http://doi.org/10.1063/1.4945660

[2] Fitié, C. F. C., Roelofs, W. S. C., Magusin, P. C. M. M., Wübbenhorst, M., Kemerink, M., & Sijbesma, R. P. (2012). Polar Switching in Trialkylbenzene-1,3,5-tricarboxamides. The Journal of Physical Chemistry B, 116(13), 3928–3937. http://doi.org/10.1021/jp300008f

[3] Gorbunov, A. V., Putzeys, T., Urbanavičiūtė, I., Janssen, R. A. J., Wübbenhorst, M., Sijbesma, R. P., & Kemerink, M. (2016). True ferroelectric switching in thin films of trialkylbenzene-1,3,5-tricarboxamide (BTA). Phys. Chem. Chem. Phys. http://doi.org/10.1039/C6CP03835B

[4] Gorbunov, A. V., Haedler, A. T., Putzeys, T., Zha, R. H., Schmidt, H. W., Kivala, M., Urbanavičiūtė, I., Wübbenhorst, M., Meijer, E. W., Kemerink, M. (2016). Switchable Charge Injection Barrier in an Organic Supramolecular Semiconductor. ACS Applied Materials & Interfaces, acsami.6b02988. http://doi.org/10.1021/acsami.6b02988


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Last updated: 09/05/16