Depth profiling of the degradation of OC1OC10-PPV monitored by positron beam analysis

• Published in: Synthetic metals Vol. 138; no. 1-2; pp. 43 - 47
• Main Authors: ALBA GARCIA, A, SCHUT, H, SIEBBELES, L. D. A, VAN VEEN, A
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Lausanne Elsevier Science 02.06.2003; Amsterdam; New York, NY
• Subjects: Applied sciences; Crosslinking and degradation; Exact sciences and technology; Physicochemistry of polymers; Polymers and radiations; Polymer; Phenylenevinylene derivative polymer; Positron annihilation; Doppler effect; Experimental study; Thin film; Degradation; Conjugated polymer; Ultraviolet radiation; Investigation method; Laser beam; Depth profile; PPV; Photochemical degradation; Positron
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(02)01263-8

The Doppler broadening of annihilation radiation (DBAR) technique and UV-Vis photo-absorption spectroscopy were used to monitor the photo-oxidation of thin films (200nm) of OC1OC10-PPV. Samples were exposed in air to a 308nm excimer laser and a commercial UV-Vis lamp. By means of the DBAR technique, the degradation was monitored as a function of depth when illuminating from the polymer side or the substrate side. It showed that the degradation is more pronounced on the side where the light affects, indicating that the photo-oxidation is not limited by oxygen diffusion. DBAR results were compared to photo-absorption measurements showing that in the first stages of the photo-oxidation positrons were more sensitive to changes in the polymer film. The non-destructive character of the DBAR technique and the possibility to perform depth profiling makes it a promising technique to study multi-layer devices.