Effects of ferromagnetic nanowires on singlet and triplet exciton fractions in fluorescent and phosphorescent organic semiconductors

We report a magnetic field-dependent electroluminescence (EL) induced by ferromagnetic Co53Pt47 nanowires in fluorescent conjugated polymer poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] and phosphorescent iridium-complex Ir(ppy)3 molecules. The photoluminescence and EL studies indicate that the dispersed CoPt nanowires increase the singlet-to-triplet exciton ratio in organic semiconductors, suggesting that the spin-polarized holes were injected into the organic molecules from the CoPt nanowires under electrical excitation. Therefore, the use of ferromagnetic nanomaterials demonstrates a pathway to tune the optoelectronic properties that are related to singlet and triplet states in organic semiconducting materials.