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2018 Wilken Seemann

(Institute of Solid State Phycics) visiting the National School of Higher Studies Unit Morelia, National Autonomous University of Mexico (ENES Morelia UNAM)

17 January - 8 May 2018

- Intermediate Report -

Starting mid-January 2018 I have had the opportunity to visit the National Autonomous University of Mexico (UNAM), campus Morelia. Here I am working with Dr. Alejandra Castro-Carranza, research ambassador of the University of Bremen in Mexico and guest in the group “Science of Sustainable Materials” - ENES Morelia UNAM, in order to conduct electrical characterization and modeling of the semiconducting polymer P3HT for sensing applications. For this purpose, it has been combined with glyphosate, a commonly used pesticide which has been found to be genotoxic in humans [1]. These electrical experiments will complement an optical analysis that has been performed in Bremen. In addition, it is worth mentioning that I am the first student to be exchanged in a collaboration between ENES Morelia UNAM and the University of Bremen.

As of now – I am writing this intermediate report nearly one month into my stay – electrical characterization has been performed on hybrid P3HT:glyphosate heterojunctions (diodes) in cooperation with Dr. Jairo C. Nolasco. We have observed evidence of a sensing effect; however, the interface has to be improved. It is planned to include a PEDOT:PSS conducting interlayer at the contact interface. Furthermore, an in depth characterization of this hybrid blend will be performed using thin-film-transistors and the analysis of their transfer and output characteristics. Up to now, discussions of the results obtained in Bremen and Morelia with the group “Science of Sustainable Materials” have been very fruitful, as there will be additional input from theoreticians, i.e., Dr. Yesenia Arredondo and Dr. Claudia Briones-Jurado, who will model the molecular interactions within the hybrid blend in order to better understand our experimental results.

I am convinced that the experience I am gaining here in electrical measurement techniques and modeling will surely be very helpful for future projects as for example a planned PhD project in Bremen.

Finally, I, as well as the responsible persons in Bremen and Morelia, hope that my stay here can foster a stronger collaboration between both Universities, including an exchange of more students in the future.

[1] J.V. Tarazona, D. Court-Marques, M. Tiramani, H. Reich, R. Pfeil, F. Istace and F. Crivellente: Glyphosate toxicity and carcinogenicity: a review of the scientific basis of the European assessment and its differences with IARC, Archives of Toxicology 91 (2017), 2723-2743.

Wilken Seemann
Updated by: MAPEX