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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: Organic Electronics and Photovoltaics - Hybrid and Organic Layer Systems
CPP 13.5: Talk
Monday, March 12, 2018, 16:00–16:15, C 243
Hot electrons and hot spins at metal-organic interfaces — •Thorsten Arnold1, Ainhoa Atxabal2, Subir Parui2, Luis E. Hueso2, and Frank Ortmann1 — 1Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany — 2CIC nanoGUNE, 20018 Donostia-San Sebastian, Basque Country, Spain
Metal-organic barriers between the metal Fermi energy and the molecular levels of the organic semiconductor play a fundamental role in the performance of organic electronic devices. In order to measure these barriers, recently, a hot-electron transistor device has been developed [1]. We propose a theoretical model [2], which describes all the transport effects of the hot electrons for the first time. The model is able to reproduce the experimental results with excellent accuracy.
The model is extended to predict the transport characteristics of spin-polarized hot electrons in these devices. We find a spatial variation of the spin diffusion length, which scales inversely proportional to the variation of the electron density. The spin current can be increased by increasing the hot electron energy and by decreasing the image charge barrier without changing the spin diffusion length. We also provide unprecedented insight into the effects of disorder at the metal-organic interface. Finally, we establish conditions when pure spin currents appear, where majority and minority spin carriers propagate in opposite directions.
[1] A. Atxabal et al., Adv. Mater. 29, 1606901 (2017).
[2] T. Arnold et al., Adv. Funct. Mater. (to be published).