Spin-polarized carrier injection through hybrid ferromagnetic electrode for enhanced optical efficiency of organic light-emitting diodes

Abstract

Organic light-emitting diodes (OLEDs) with an enhanced optical efficiency were fabricated using a hybrid ferromagnetic (FM) electrode that injected spin-polarized carriers (spin-polarized current). The optical efficiency of the fluorescent OLEDs was increased through the injected spin-polarized carriers, which increased the formation ratio of singlet to triplet exciton. The OLED with the hybrid FM electrode exhibited enhancements of 66.6% in the external quantum efficiency at 50 mA/cm2 and 31.8% in the power efficiency at 500 cd/m2, compared with a reference device at room temperature. The hybrid FM electrode was designed using the finite-difference time-domain method to obtain a high optical efficiency while preventing spectrum distortion.