AVS 53rd International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThP

Paper AS-ThP9
Surface Characterization for MEH-PPV of Difference Molecular Weight Analyzed by XPS and SPM

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Aspects of Applied Surface Science Poster Session
Presenter: I. Yoshitoki, JEOL Ltd., Japan
Authors: N. Keiichi, JEOL Ltd., Japan
I. Yoshitoki, JEOL Ltd., Japan
O. Toshiyuki, JEOL Ltd., Japan
Correspondent: Click to Email
It is well known that x-ray photoelectron spectroscopy (XPS) is a meaningful analytical technique for the chemical characterization of polymer compounds. In particular, surface segregation occurs by a change of molecular weight in polymer. Recently, the development of organic EL materials advances, and the characteristic of these materials are analyzed by various analysis instruments. Usually, structural analysis of organic EL materials is investigated by GC-MS and NMR. On other hand, XPS is used for surface chemical composition analysis mainly. However, organic EL materials are different in a characteristic by a difference of molecular weight. In particular, EL luminous efficacy of high polymer materials shows molecular weight dependence. In this work, we examined the chemical bonding state and structure of different molecular weight organic EL material. We have investigated MEH-PPV [poly(2-methoxy,5-(2f-ethyl-hexyloxy)-p-phenylenevinylene)] of different molecular weight. This MEH-PPV die formation with THF solvent on ITO film. X-ray photoelectron spectrometer used for this experiment is JPS-9200 (JEOL.Ltd.), and the measurement condition is as follows. X-ray used this measurement is AlK@alpha@ monochromatic x-ray, and energy resolution for each elements is 0.65 eV. The surface was observed with SPM (JSPM-5400, JEOL Ltd.). The next results were provided from XPS measurement. It was observed that the amount of C-O group decreased with increase of molecular weight, and CH peak intensity and FWHM of CH peak increased. After decrease of surface segregation, as for the increase of CH peak intensity and FWHM, recombination of hole and electron occurs in CH intramolecule.