OLEDs based on multi-emission by a single emitter

Abstract

Organic light-emitting diodes (OLEDs) are solid state thin film devices composed of stacked organic layers sandwiched between two electrodes. Light is generated in the electroluminescent layer containing an emissive (for example metal complex or polymer). Generally, in order to generate white-light emitting OLED (WOLED), the OLED organic stack has to contain red, green and blue emitters. Herein, we report WOLED where a platinum complex having di(2-pyridinyl)benzene-based tridentate ligand is the only emitter in the emitting layer. The Pt complex, which emits in the blue region, has a planar structure and thus has a tendency to form luminescent red-shifted aggregates. At the concentration of 20% in the emitting layer, the balanced contributions of monomeric and aggregate emissions of the Pt complex yield white light. The performance of WOLEDs devices of new architecture was studied. Luminance reaches 18000 cd/m2 and external electroluminescent efficiency is 7%. White light emitted by the devices is characterized by CIE (0.42, 0.38) and CRI = 65.