Improved out-coupling efficiency from a green microcavity OLED with a narrow band emission source

A highly efficient green microcavity organic light emitting diode was developed using a tetradentate cyclometalated platinum complex, PtN1N, with an intrinsically narrow emission spectral band (FWHM = 18 nm). Devices employing the narrow band emitter in MOLEDs consisting of a single pair of a high index dielectric, Ta2O5, and low index dielectric, SiO2, exhibited a high peak external quantum efficiency of 33.7% compared to a standard OLED in the same device architecture with a peak external quantum efficiency of 25.6%. We have also found in our study that narrow band emission sources in tuned microcavity OLEDs exhibit larger enhancements in light out-coupling efficiency accompanied by small changes in color with respect to viewing angle compared to broad band emitters which is advantageous in display applications.