A systematic study on efficiency enhancements in phosphorescent green, red and blue microcavity organic light emitting devices

A systematic study has been conducted on microcavity organic light emitting diodes (OLEDs) based on green, red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters. We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green, red and blue emitters. While the luminance enhancements of blue and red phosphorescent microcavity devices are small, a current efficiency as high as 224 cd A(-1) is obtained in the green phosphorescent microcavity OLEDs.