ORGANIC ELECTROLUMINESCENT ELEMENT AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To set ionization potential(Ip) of a positive electrode interfacial part making contact with a hole injection transporting layer at a required value, in the manufacture of a reverse-type organic EL element. SOLUTION: A negative electrode 3, an insulating layer 4, an electron injection layer 5, an electron transporting layer 6, a light emitting layer 7 and a hole infection transport layer 8 are formed on a substrate 2. A positive electrode 9 of an ITO film is formed through sputtering method on the surface of the hole injection transport layer 8 in the atmosphere of Ar:O2 mixture gas. An interfacial part 12 is formed under the condition that Ar:O2=25 sccm:10 sccm, and a remaining portion 13 is formed under the condition of 25 sccm:1 sccm for the ratio. Ip of the interfacial part 12 becomes 6.0 eV, and resistance becomes 300Ω. The Ip of the portion 13 is 4.5 eV, and resistance is 100Ω. The sheet resistance of the positive electrode 9 as a whole is less than 100Ω/(square) and the Ip is 5.5 eV. The resistance of the positive electrode 9 of ITO as a whole is small, and the Ip of the interface with the hole injection transporting layer 8 approximates that of the hole injection transport layer 8. Thus, a good hole-injecting characteristic is obtained, and higher luminance is obtained.