Patent ID: 9006711
Filing Date: 2015-04-14
Classification: C09K,H01L,H05B,Y02B

Abstract:
1. A white organic electroluminescent element comprising: light emitting layers between an anode and a cathode, wherein the light emitting layers include: a light emitting layer A which contains a host compound and a phosphorescence emitting dopant exhibiting a maximum emission wavelength of 480 nm or less; and a light emitting layer B which contains a phosphorescence emitting dopant exhibiting a maximum emission wavelength of 510 nm or more, provided that the light emitting layer B is located between the light emitting layer A and the anode; and a concentration of the phosphorescence emitting dopant in the light emitting layer A changes in a thickness direction of the light emitting layer A, wherein the concentration of the phosphorescence emitting dopant contained in the light emitting layer A is decreased from a side of the anode to a side of the cathode in a thickness direction of the light emitting layer A; wherein the phosphorescence emitting dopant contained in the light emitting layer A has at least one of partial structures represented by Formulas (A) or (B): wherein Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group; Rb and Rc each represent a hydrogen atom or a substituent; Al represents a group of atoms necessary to form an aromatic ring or an aromatic heterocyclic ring; and M represents Ir or Pt, wherein Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group; Rb, Rc, Rb Al represents a group of atoms necessary to form an aromatic ring or an aromatic heterocyclic ring; and M represents Ir or Pt; and the host compound contained in the light emitting layer A is represented by Formula (a): wherein X represents O; Ar represents an aromatic ring; and n is an integer of 0 to 8.