Influence of the singlet exciton fission process at different temperatures on the magneto-electroluminescence in the rubrene-based organic light emitting device
The organic light-emitting diodes with a thin rubrene layer were fabricated.The magnetic field effects on electroluminescence (MEL) were investigated under different temperatures (15 K≤T≤300 K).Results show that the line shape and the magnitude of the MEL in rubrene-based devices are different in comparison with the reference devices.For the reference devices, the MEL increases sharply in the low-field but saturates slowly in the high-field at room temperature.However, for the rubrene-based device, the magnitude of the MEL is suppressed in the low-field range but continues to increase in the high-field.Moreover, those properties of the MEL show temperature depend-ence.Red shift with decreasing temperature is also observed from its spectrum.A composite model has been proposed based on the hyperfine interaction, the magnetic field-mediated singlet exciton fission process (STT) process and the triplet-triplet annihilation process (TTA).We suggested that, at room temperature, the MEL behaviors of rubrene-based devices are contributed to the hyperfine interaction and STT process, while hyperfine interaction and TTA process are dominated at 15 K.
rubrene luminousmagnetic effecttemperature effectSTT processTTA process
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