METHOD OF MANUFACTURING ORGANIC ELECTROLUMINESCENT DEVICE
A method of manufacturing an organic electroluminescent device is provided. First, a substrate and an anode on the substrate are provided, and then, an organic electroluminescent material layer is formed on the anode. Next, a multi-layer transparent cathode is formed on the organic electroluminescent layer. The step of forming the multi-layer transparent cathode comprises performing a co-evaporation process to form a doped buffer layer comprising electron transport materials and dopant so as to distribute the dopant uniformly in the electron transport materials.
1 . A method of manufacturing an organic electroluminescent device, comprising:
providing a substrate and an anode on the substrate;
forming an organic electroluminescent material layer on the anode; and
forming a multi-layer transparent cathode on the organic electroluminescent layer, the step of forming the multi-layer transparent cathode comprising:
forming a thin metal layer on the organic electroluminescent material layer;
performing a co-evaporation process to form a doped buffer layer comprising electron transport materials and dopant on the thin metal layer so as to distribute the dopant uniformly in the electron transport materials; and
forming a transparent electrode on the doped buffer layer.
2 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the electron transport materials is selected from tris(8-quinolinato-N1,08)-aluminum (Alq3) and bis(10-hydroxyben-zo[h]quinolinato) beryllium (Bebq2).
3 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the dopant comprises metal materials.
4 . The method of manufacturing the organic electroluminescent device as claimed in claim 3 , wherein the metal materials have a work function of less than or equal to 4.2 electron volts (eV).
5 . The method of manufacturing the organic electroluminescent device as claimed in claim 3 , wherein the metal materials are selected from alkali metals, alkali earth metals, transition metals, or rare earth metals.
6 . The method of manufacturing the organic electroluminescent device as claimed in claim 5 , wherein the metal materials are selected from lithium (Li), cesium (Cs), strontium (Sr), or samarium (Sm).
7 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein a dopant concentration of the doped buffer layer is about 0.1-99% by weight.
8 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein a dopant concentration of the doped buffer layer is about 0.1-30% by weight.
9 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the doped buffer layer has a thickness of about 1 nm to 50 nm.
10 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the thin metal layer has a thickness of about 1 nm to 20 nm.
11 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the thin metal layer comprises aluminum (Al), silver (Ag), barium (Ba), calcium (Ca), magnesium (Mg)/Ag alloy, Al/Li alloy, or Al/Ba alloy.
12 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the transparent electrode has a thickness of about 10 nm to 400 nm.
13 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the transparent electrode comprises indium tin oxide (ITO) or indium zinc oxide (IZO).
14 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the substrate comprises glass, plastic foil or metal foil.
15 . The method of manufacturing the organic electroluminescent device as claimed in claim 1 , wherein the anode comprises ITO, IZO, aurum (Au), or platinum (Pt).