AVS 47th International Symposium
    Organic Films and Devices Wednesday Sessions
       Session OF-WeP

Paper OF-WeP5
Photoemission Investigation of Metal/CuPc Interfaces

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: L. Yan, University of Rochester
Authors: L. Yan, University of Rochester
Y. Gao, University of Rochester
M.G. Mason, Eastman Kodak Company
C.W. Tang, Eastman Kodak Company
Correspondent: Click to Email
Metal/organic interface play an important role in organic light emitting diodes (OLED), which has been a very active field in the past few years because of their scientific and commercial significance. Copper phthalocyanine (CuPc) has been found to improve the electron injection when it is inserted as a buffer layer between the metal cathode and Tris(8-hydroxyquinoline) aluminum (Alq@sub 3@), the mostly used light emitting material in OLED. It is intriguing that CuPc, traditionally used as a hole transport material in OLED, can enhance electron injection at the cathode. To address this question, we investigated the formation and the energy level alignment at the interface between metals and CuPc, using X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) simultaneously. We found that unlike many other organic materials, CuPc has two components in C1s, whose relative intensity varies as the interface formation progresses. This property provides a unique avenue to determine the charge transfer, dipole formation and energy level alignment at the interface.