Microcavity Organic Light Emitting Diodes with Higher Order Resonance Modes

Organic light emitting diodes (OLED) have a characteristic broad spectral width. The output emission characteristic of the light source can be controlled by the use of a microcavity. A microcavity OLED has metal electrodes encasing the organic layer which allow for the unique bandwidth narrowing and angle resolved spectral emission. We investigate the emission spectrum through the fundamental and higher order resonant modes using a single organic emitter molecule, just by designing the microcavity structure alone. We use Tris(8-hydroxyquinolinato)aluminium, Alq3, as the emissive layer (EML) with the electron transport layers (ETL) and hole transport layers (HTL) added in between the metal electrodes. The output characteristic (spectral bandwidth and viewing angle) of the microcavity is affected by its optical path length. The desired design is achieved by varying the thickness of the ETL, EML, and HTL layers which make up the microcavity. We generate the full visible spectrum at the forward emission and the angle resolved emission spectrum for various order resonance modes.