ISSN:
1662-9779
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Physik
Notizen:
Thin layers of the OLED related polyphenylene-vinylene (PPV) deposited by a precursoron micro-fabricated Si cantilevers were studied by applying the vibrating-reed technique duringrepeated temperature cycling between 100 and 520 K. By means of the Langmuir-Blodgett methodfor film production, the dependence of damping and elastic modulus on well defined values of filmthickness (16 to 69 nm) was determined. Simultaneous measurements of these quantities showedfour damping peaks during heating around 130 K (called γ), 250 K (β), 350 K (β’), and 400 K(called C). Three of them (γ, β’, C) disappeared after heating to the highest temperature (520 K)indicating their presence in the precursor only. The activation parameters of the relaxation peaks (γ,β, β’) were estimated and assigned to specific atomic movements in the molecule. Peak C occursduring the conversion process of precursor to polymer. Earlier results are essentially substantiated,indicating only slight differences to those for layers produced previously by spin coating. The observedthickness dependence of damping for the γ and β peaks suggests a weaker contribution ofmolecules in the surface region than of those in the bulk, while the β’ peak is supposed to resultfrom molecules in the interface region between layer and substrate
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.137.189.pdf
