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

Abstract

We report a magnetic field-dependent electroluminescence (EL) induced by ferromagnetic ${\mathrm{Co}}_{53}{\mathrm{Pt}}_{47}$ nanowires in fluorescent conjugated polymer poly[2-methoxy-5-($2^{\prime }$ -ethylhexyloxy)-1,4-phenylenevinylene] and phosphorescent iridium-complex $\mathrm{Ir}{\left(\mathrm{ppy}\right)}_3$ 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.