Semitransparent metal or distributed Bragg reflector for wide-viewing-angle organic light-emitting-diode microcavities

Abstract

Microcavities for organic light-emitting devices (OLED’s) with a metal mirror on one side and a distributed Bragg reflector (DBR) on the other side have been extensively studied in the literature. Usually the DBR is highly reflective, and the resulting emission of the microcavity depends strongly on angle and wavelength. With a thick metal mirror on one side and a semi-transparent metal mirror on the other side of the OLED, a microcavity can be obtained with an optical thickness of 1 half-wavelength. Because the emission is enhanced over a wide solid angle, with a small spectral dependence, this structure is very promising for display applications. For a TPD/ALq3 structure with a typical intrinsic emission spectrum, embedded in a microcavity with a thick and a semitransparent silver mirror, the integrated emission in air, the color variation with angle, and the change in the decay time are compared with those in a DBR-based microcavity.