White top-emitting organic light-emitting diodes employing tandem structure

A high-efficiency white top-emitting organic light-emitting diode (TOLED) is demonstrated by introducing tandem structure. The microcavity effects are used to finalize the configuration of the tandem white TOLED. The resultant tandem white TOLED emits a complementary-color white light with the Commission Internationale de L'Eclairage coordinates of (0.39, 0.43) and the color-rendering index of 70, which retains high color stability towards driving voltage. The maximum forward viewing external quantum efficiency and current efficiency of the device are 16.9% and 41.1 cd/A, respectively. The employment of the tandem structure can be an alternative method to fabricate white TOLEDs for practical applications.