Magneto‐Electroluminescence Responses Mediated by Magneto‐Conductance in Polymer and Thermally Activated Delayed Fluorescence‐Emitter‐Based Light‐Emitting Diodes

Abstract

The magneto‐electroluminescence (MEL) responses of polymer and thermally activated delayed fluorescence‐emitter‐based light‐emitting diodes (TADF LEDs) under constant voltage and current regimes are characterized to elucidate that the current as regulated by magneto‐conductance (MC) mediates MEL of devices. Through the analytical fitting of MC and MEL curves, it is disclosed that MC (as interpreted by the polar pair model) partially involves the changes in the curve features, magnitudes, and shapes of MEL responses. A negative curve feature in the MEL response of TADF‐based LEDs is visualized under the electric bias in a low magnetic field regime. This feature should be attributed to the mediation of the MEL by the negative MC due to the unbalanced carrier dynamics of the device. When carrier dynamics are balanced, the specific negative curve feature at low magnetic field regime disappears. In this work, the solid correlation between the MEL and MC responses is revealed and the negative curve feature of MEL under the constant voltage at the low magnetic field regime that involves the contribution from the triplet exciton charge reaction in TADF‐based LEDs is validated.