AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP11
XPS and FTIR Characterization of C60 States in C60 Doped Conducting Polymers

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: H. Kato, Kanto Gakuin University, Japan
Authors: H. Kato, Kanto Gakuin University, Japan
S. Takemura, Kanto Gakuin University, Japan
K. Iwasaki, Kanto Gakuin University, Japan
N. Nanba, Kanto Gakuin University, Japan
T. Hiramatsu, Kanto Gakuin University, Japan
O. Nishikawa, Kanazawa Institute of Technology, Japan
M. Taniguchi, Kanazawa Institute of Technology, Japan
Correspondent: Click to Email
Conducting polymer polythiophene (PT) film incorporated with C60, highly functional molecule, was prepared by electrochemical doping and diffuse injection methods. Charge transfer and interaction between the doped dye molecule and PT polymer chains were investigated by XPS analysis of the core-level energies and spectral profiles of the atomic components. Vibration states of the doped dye molecule and the polymer backbone were also investigated by FTIR RAS and FTIR transmission in order to examine the dopant-chain interaction in the hybrid films. The XPS spectral profile of the electrochemical doping sample was different from that of the casting sample, which reflects the different dopant-chain interaction in polymer films. It is known that C60 is a highly symmetrical molecule with HOMO fivefold (hu) and LUMO threefold (t1u) enables various valence values to be possible filling the degenerate LUMO levels with different number of electrons. The higher binding energy peaks of C 1s reflect the valence values of C60. FTIR transmission measurement clarified that C60 molecules were doped in the polymer film by both methods of electrochemical doping and casting because characteristic peaks due to the vibrational modes of C60 were observed. The C60 originated peaks were also observed in the FTIR RAS spectra. The peaks due to C60 were differently observed in the spectra of electrochemical doping and casting samples reflects the different doping states of C60. The results of XPS and FTIR suggests the controllability of conductive state of PT by changing dopant valence values by electrochemical doping methods. XPS core-level analysis of S 2p was composed of several peak components. The energy position of the main peak is almost positioned in the reference value. The lower energy and the higher energy components reflect the charge transfer between polymer chain and C60 molecule. The present work supported by "High-Tech Research Center" Project aided by MEXT.