Comparative Raman study of photo-oligomer stability in the donor-acceptor fullerene complex {Pt(dbdtc)2}·C60 and pristine C60

K. P. Meletov – Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region, Russia; mele@issp.ac.ru
J. Arvanitidis – Aristotle University of Thessaloniki, GR-54 124 Thessaloniki, Greece
D. Christofilos – Aristotle University of Thessaloniki, GR-54 124 Thessaloniki, Greece
G. Kourouklis – Aristotle University of Thessaloniki, GR-54 124 Thessaloniki, Greece

The photopolymerization process and the stability of the C60 photo-oligomers at elevated temperature in the molecular donor-acceptor fullerene complex {Pt(dbdtc)2}·C60 (C60 complex with platinum dibenzyldithiocarbamate) and pristine fullerite C60 are studied by Raman spectroscopy. Fast polymerization, manifested by the appearance of additional peaks in the frequency region of the Ag(2) pentagon-pinch (PP) mode of the C60 molecule, was observed upon sample illumination at 514.5 and 532 nm, even at low laser power density as well as at 785 nm at higher power density. The frequencies of the new peaks are in accordance with the empirical dependence of the PP-mode frequency on the number of the sp3-like coordinated carbon atoms per molecular cage. The temperature dependence of the polymer content under constant laser power density reveals the decomposition of the photo-oligomers to monomers at ~ 350 K in the fullerene complex {Pt(dbdtc)2}·C60 and at ~ 410 K in the case of the pristine C60. These values are considerably smaller than the decomposition temperature of 525 – 565 K for the crystalline polymers of C60.

Keywords: fullerene, molecular complexes, Raman spectroscopy, photopolymerization.

PACS 78.30.Na

DOI 10.17586/2220-8054-2016-7-1-125-132


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