Highly efficient organic electroluminescent device

An organic electroluminescent device, comprising:

• a first electrode;
• a second electrode;
• and
• one or more organic luminescent media, including an emission layer, wherein the emission layer comprises:
• a doping layer having both host material and doping material;
• and
• a non-doping layer having only said host material, wherein at least a portion of the non-doping layer is in contact with at least a portion of the doping layer, and wherein an ionization potential energy of a material in the non-doping layer of the emission layer is higher than an ionization potential energy of a material in the doping layer of the emission layer.

A method of making an organic electroluminescent device, comprising:

• forming an anode, a hole injection layer, and a hole transport layer sequentially on a substrate;
• forming an emission layer that includes a doping layer and a non-doping layer, wherein an ionization potential energy of a material in the non-doping layer of the emission layer is higher than an ionization potential energy of a material in the doping layer of the emission layer;
• and
• forming an electron injection layer, an electron transport layer, and a cathode sequentially on the emission layer.

A method of making an organic electroluminescent device, comprising:

• forming an anode on a substrate;
• forming one or more hole-related layers on the anode;
• forming an emission layer that includes a doping layer and a separate non-doping layer, wherein an ionization potential energy of a material in the non-doping layer of the emission layer is higher than an ionization potential energy of a material in the doping layer of the emission layer;
• forming one or more electron-related layers on the emission layer;
• and
• forming a cathode on the one or more electron-related layers.

An organic electroluminescent device, comprising:

• an anode;
• a cathode;
• at least one electron related layer;
• at least one hole related layer;
• and
• at least one emission layer which includes a first region having host material and doping material, and a second region having host material and no doping material.