Effects of Green Emission on the Performance of White Organic Light-Emitting Devices and Their Electroluminescent Characteristics

A white organic light-emitting device (WOLED) using tris(8-hydroxyquinoline)aluminum (Alq(3)) as the green emission is demonstrated. Our experiments indicate that Alq(3) doping not only improves the color coordinates and color stability, but also reduces current-induced fluorescence quenching. A maximum luminous efficiency of 8.87 cd/A and an applicable value of 7.92 cd/A at 20 mA/cm(2) are obtained. The excellent performance predominantly results from the effective energy transfer in the emitting system and the efficient utilization of Alq(3) green emission. For comparison, WOLEDs with different components as the green emission and without the component of green emission are also fabricated and investigated. Our results show that the introduction of green emission from an appropriate component significantly improves the device efficiency and color properties. This result is further verified on the basis of the theory of exciton generation and diffusion.