Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 86: Organic electronics and photovoltaics V (CPP, jointly with HL, O)

HL 86.12: Vortrag

Donnerstag, 14. März 2013, 18:15–18:30, H34

Magnetoresistive Field-Effect Transistors based on Spiro-TAD/Spiro-PFPy Donor/Acceptor-Blends — •Thomas Reichert, Carolin Isenberg, Tobat Saragi, and Josef Salbeck — Macromolecular Chemistry and Molecular Materials (mmCmm), Department of Mathematics and Science and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132, Kassel, Germany.

One promising opportunity for the realization of next generation magnetooptoelectronic devices is the use of the electron spin as an additional control parameter. In organic semiconductors the spin states of quasiparticles can be adjusted with low magnetic fields, which leads to large (up to 20% at 10mT) magnetoresistive effects at room temperature. We show that the sign of magnetoresistance (MR) in organic field-effect transistors (OFETs) can be tuned from positive to negative by simply applying illumination. In darkness an external magnetic-field increases the resistance (positive MR) while a magnetic-field induced resistance decrease (negative MR) can be achieved under illumination. The key aspect of this promising effect is the application of co-evaporated Spiro-TAD/Spiro-PFPy blends as the charge transport layers in OFETs. Due to the hole (electron) stabilizing properties of Spiro-TAD (Spiro-PFPy) a mixed donor/acceptor blend is formed, which leads to the observed photoinduced MR sign change. This effect can pave the way to future multifunctional spintronic devices.