Efficiency Enhancement of Organic Light-Emitting Diodes with Multifunctional Magnetic Composite Nanoparticles of Fe3O4@Au@SiO2

Multifunctional nanomaterials have been widely utilized to optimize the performances of optoelectronic devices. In this work, magnetic composite nanoparticles (NPs) of Fe3O4@Au@SiO2 are used as dopants to improve the quantum efficiency of electroluminescence of the tris-(8-hydroxyquinoline) aluminum-based organic light emitting devices (OLEDs). As a result, the performances of doped OLED (Von = 2.8 V, L = 23400 cd/m2, EQE = 1.55) are obviously boosted as compared to the control device (Von = 2.9 V, L = 19780 cd/m2, EQE = 1.27). Especially, the current efficiency of fluorescent green OLEDs can be 22.5% enhanced by simply mixing the magnetic Fe3O4@Au@SiO2 (0.5 wt‰) NPs into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), yielding the maximum value of 4.62 cd/A. The efficiency enhancement could be attributed to the collective effects of light-scattering, localized surface plasmon resonance (LSPR) and magnetic effect induced by magnetic composite NPs.