Efficient blue and white organic light-emitting devices based on a single bipolar emitter

Excellent bipolar carrier transport properties of 2,7-dipyrenyl-9,9′-dimethyl-fluorene (DPF) have been elucidated by using different device structures. A nondoped device using DPF as host emitter showed highly-efficient blue emission with a maximum efficiency of 6.0cd∕A and CIE coordinates of x=0.15 and y=0.19. Another device based on rubrene-doped DPF as emission layer gave pure high-efficiency white emission with good color stability, a maximum efficiency of 10.5cd∕A, and CIE coordinates of x=0.28 and y=0.35. The excellent bipolar transport capability and high performance as both emitter and host suggest that DPF is an efficient and versatile material for various applications in organic light-emitting devices.