Effect of $g$-factor anisotropy in the magnetoresponse of organic light-emitting diodes at high magnetic fields

Effect of $g$ -factor anisotropy in the magnetoresponse of organic light-emitting diodes at high magnetic fields

Daniel Nikiforov, Bagrat Khachatryan, Jenya Tilchin, Efrat Lifshitz, Nir Tessler, and Eitan Ehrenfreund

Phys. Rev. B 98, 235204 – Published 17 December 2018

Abstract

We report the magnetic field and temperature dependences of magnetoconductance (MC) and magnetoelectroluminescence (MEL) in organic light emitting diodes (OLED) made of homopolymer organic layers. We show that in these OLEDs a spin mixing mechanism due to the anisotropy of the organic layer $g$ factor has a significant effect in the measured MC( $B$ ) and MEL( $B$ ) at fields of order of $\sim 1 T$ . We discuss the model of spin mixing among polaron pairs due to the anisotropy of the $g$ factor and show that it can be described as an angle dependent $Δ g$ mechanism that is known to have significant magnetoresponse effects. We show that the internal structure of the polaron pair is material dependent rationalizing thus the differences in their electrical mobility.

Received 2 July 2018
Revised 13 September 2018

DOI:https://doi.org/10.1103/PhysRevB.98.235204

Physics Subject Headings (PhySH)

Electroluminescence Magnetoresistance Magnetotransport Spin dynamics

Organic LEDs Organic semiconductors

Resistivity measurements

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Daniel Nikiforov^1,2, Bagrat Khachatryan^1,2, Jenya Tilchin^2,3, Efrat Lifshitz^2,3, Nir Tessler⁴, and Eitan Ehrenfreund^1,2,*

¹Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
²Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
³Shulich Chemistry Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
⁴Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel

^*Author to whom correspondence should be addressed: eitane@technion.ac.il

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Issue

Vol. 98, Iss. 23 — 15 December 2018

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Physical Review B

covering condensed matter and materials physics