Free Electron Laser-Polymerization of C60 Grown by Liquid-Liquid-Interfacial Precipitation Method

The purpose of this work is to synthesize a three-dimension C60 polymer using photo-polymerization method. The used pristine materials were C60 precipitates prepared by a liquid-liquid interfacial precipitation (LLIP) method. The prepared LLIP material was set in the vacuum and was compressed in the anvil with the pressure of 600MPa or 7GPa. The 4th harmonics FEL with the wavelength of 500nm was irradiated with macro-pulses (the pulse width of 20µs) containing very short micro-pulses (the pulse width of 200fs). The Raman Ag(2) peak of C60 molecules in the vicinity of 1469cm-1 becomes broad and shifts to the lower energy region as proceeding of polymerization. Under high pressure and/or FEL irradiation the LLIP crystal revealed the large red-shift and the increment of the half width of the Raman Ag(2) peak. Furthermore the LLIP crystal mixture with iodine revealed the more distinctive red-shift, ca. 13cm-1 because of highly packing of C60 molecules. The C60 molecular accession by LLIP process and/or the photo-assisted hole-doping from iodine were promising conditions to promote the photo-polymerization effectively.