| Popis: |
C60 forms very rigid insoluble films (“monolayers”) at the air-water interface (collapse pressure nc=62.5 mN/m). The “area per molecule” values AO= 21.6 A2 (at 11=0) and Ac=11.5 A2 (at IIc) suggest that more than 4 C60 molecules are piled atop each other, per “monolayer”. These films were transferred to glass and HOPG as Langmuir-Blodgett (LB) films, and to a Cu grid as Langmuir- Schaefer films. These films have 2-D and 3-D crystalline regions, seen by scanning tunneling microscopy (STM) and high resolution elecron microscopy (HRTEM). The STM image is a {013} face-centered cubic (FCC) projection , a= 14.2 A. The HRTEM micrographs and a selected-area diffraction pattern show an FCC lattice, a = 14.20 ± 0.05 A. When optimally “doped” with potassium, an LB film of 50 “monolayers” of C60 on polyethylene terephthalate shows a low-field susceptibility signal (LFS) at or below 8.1 K: this is the first report of superconductivity in an LB film. |
