Magnetic field effects (MFE) have been extensively studied in organic light emitting diodes because of their potential application in organic spintronics devices. However, only a few studies on MFE in organic light-emitting electrochemical cells (LEC) have been reported. In this paper, magnetic field effects on the electroluminescence of an LEC device with the structure of ITO/MEH-PPV:PEO:LiCF3SO3/Al were studied at various temperatures. The luminance-current-voltage curves of the device shows the typical bi-polar characteristics of LECs; positive magnetic electroluminescence (MEL) was observed with a value of about 2.5% (B = 42 mT, 250 K), showing a Lorentzian line shape. With a decrease in temperature, the MEL value and the threshold voltage increased accordingly, below the possible mechanism is discussed.
Keywords: light-emitting electrochemical cell; magnetic field effects; organics semiconductor.