AVS 50th International Symposium
    Organic Films and Devices Tuesday Sessions
       Session OF-TuP

Paper OF-TuP4
XPS Studies of Charge Transfer between Dye Molecules and Polymer Chains in Dye Molecule Doped Conducting Polymer Films

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: H. Kato, Kanto Gakuin University, Japan
Authors: H. Kato, Kanto Gakuin University, Japan
S. Takemura, Kanto Gakuin University, Japan
Correspondent: Click to Email
Conducting polymer polythiophene (PT) films incorporated with dye molecules such as methylene blue (MB), safranine T (ST) and brilliant green (BG) were prepared by electrochemical doping and diffuse injection methods. Polymeric structure, charge transfer and interaction between the dye molecule and PT polymer chain in the hybrid films were closely investigated by analyzing the core-level energies and spectral profiles of the atomic components. Vibrational states of the doped dye molecule and polymer backbone were also investigated by FTIR RAS and ATR in order to examine the dopant configuration into polymer chains. XPS measurements clarified the identification of doping species into the polymer chains varied with synthetic methods and conditions. Dye molecules such as MB, ST and BG were doped in polymer films as two types of states such as cation-like and salt-like. In the case of BG, XPS core-level analysis of S 2p split indicates simultaneous doping of BG cation and HSO4- in the hybrid films prepared by electrochemically reduced and dye diffused injection methods. The higher binding energy peak corresponds to HSO4- while lower binding energy peak can be assigned to the S sites of polymer backbone. Synthesized film samples were categorized into two types by the difference of S 2p core-level energy shift. In the cation-like doped sample, the energy shift of the lower peak of S 2p suggests the charge transfer between BG molecules and polymer chains creating a n-type conducting polymer state. The relation between dopant species with different configuration and dopant-chain charge transfer will be also discussed.