Recent advances in white organic light emitting diodes with a single emissive dopant

Conventional multi-layer white organic light emitting diode (OLED) devices have a structure of stacked three primary color emissive layers (EMLs) with at least three emissive dopants. This method induces different degradation rates and phase segregation among different dopants and differential color aging. OLEDs with a single emissive dopant material in an EML are employed to avoid these disadvantages. We review recent progress and development of six different methods for white OLEDs with a single emissive dopant, i.e., using (1) simultaneous emission from the host material in the EML, (2) excimer, (3) mixed-ligand molecule, (4) phosphor-sensitized fluorescent material, (5) exciplex, and (6) dual emission using excimer and exciplex.