Electrolyte-Gated Red, Green, and Blue Organic Light-Emitting Diodes.

We report vertical electrolyte-gated red, green, and blue phosphorescent small-molecule organic light-emitting diodes (OLED), in which light emission was modified by tuning the electron injection via electrochemical doping of the electron injection layer 4,4-bis(N-carbazolyl)-1,1-biphenyl (CBP) under the assistance of a polymer electrolyte. These devices comprise an electrolyte capacitor on the top of a conventional OLED, with the interfacial contact between the electrolyte and electron injection layer CBP of OLEDs achieved through a porous cathode. These phosphorescent OLEDs exhibit the tunable luminance between 0.1 and 10 000 cd m-2, controlled by an applied bias at the gate electrode. This simple device architecture with gate-modulated luminance provides an innovative way for full-color OLED displays.