Enhancement of Electroluminescence Efficiency for Organic Light-Emitting Devices due to the Introduction of the Well as Excton Confine Structure

Abstract

An organic emitting device with well structure is reported. The well structure fabricated by alternating deposition of constituent tris-(8-hydroxyquinoline) aluminum (Alq) and 4, 7-diphenyl-1, 10-phenanthroline (BPhen) layers improved the current efficiency. The enhanced efficiency can be attributed to the strong accumulation of electrons and holes in the emitting layer, which leads to an increase of the exciton formation and exciton recombination probability. The single well device exhibits the highest current efficiency of 4.12cd/A at 4V, which is more than 1.2 times than that of the conventional organic light-emitting devices. It is an effective and simple way to improve the efficiency of the organic devices by utilizing well structure as the emitting layer with proper well number.