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

We characterize the magneto-electroluminescence (MEL) responses of polymer and thermally activated delayed fluorescence emitter-based light-emitting diodes (PLEDs and TADF LEDs) under constant voltage and current regimes to elucidate that the current as regulated by magneto-conductance (MC) mediate MEL of devices. Through the analytical fitting of MC and MEL curves, we discloses that MC (as interpreted by the polar pairs model) partially involves the changes in the curve features, magnitudes, shapes, etc. of MEL responses. We observe a sharp W-shape curve feature in the MEL response of the TADF LED under the electric bias at the low magnetic field regime in our study. This result should be attributed to the mediation of the MEL by the negative MC response due to the unbalanced charrier dynamics of the device. While the carrier dynamics were balanced, the specific feature of the sharp W-shape curve disappeared. Our work clearly depicts an accurate analysis of MEL with MC response based on the polaron pairs model for studying the insight dynamics of the light-emitting LEDs and that the assessment of MEL is reliable if conduct the measurement at the constant current regime.