Influences of electric fields on the emission from organic light-emitting diodes (OLEDs) based on poly (N-vinylcarbazole) (PVK); 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP); and tris (8-hydroxyquinoline) aluminum (Alq3) were studied. There are three emission peaks at 420 nm, 520 nm, and 620 nm of the device ITO/PEDOT: PSS/PVK/BCP/LiF/Al under different driving voltages. The emissions at 420 nm and 520 nm should be from the exciton emission of PVK and Alq3, respectively. The last emission at 620 nm could be attributed to electroplex emission at the interface between the PVK and BCP layers. A high intensity white emission via electroplex formation was obtained with Commission International d'Eclairage (CIE) coordinates (0.33, 0.34) at 15 V, which is very close to the equienergy white point (0.33, 0.33).