Obtaining of hydroxylated fullerenes Y@C₈₂O_X(OH)Y, Y2@C82OX(OH)Y, Y2C2@C82OX(OH)Y and electrophysical characteristic of composite film based thereon

Abstract

The article presents, for the first time, the results of the research on composite film obtained from hydroxylated endohedral metallofullerenes (EMF) Y@C₈₂, Y₂@C_82, with Y₂C₂@C₈₂ and highest fullerenes as dopant. The composite film has been established to have electric conductivity and to be a ferroelectric with the value of residual polarization of ∼0.75 μC/cm². The impedance spectroscopy of this sample allowed us to determine dispersion of dielectric permittivity and conductivity in the range of frequencies of 0.5 Hz–100 MHz. It is stated that the value of the high-frequency dielectric permittivity of films is ε′_∞ = 2.8. However, with reduction in the electric field frequency, real and imaginary parts of ε increase to values ∼10⁴–10⁵. Such increase in dielectric permittivity is connected with increase in polarizing caused by accumulation of mobile electric charges (electrons of ions, protons) on boundaries of the structural defects of a film, which are divided by thin dielectric interlayers. The film is solid electrolyte with the ionic conductivity of ∼5 × 10⁻⁷ S/cm.

Graphical Abstract

Keywords:

• Endohedral metallofullerene
• impedance spectroscopy
• polarization

Acknowledgments

We thank A.A. Popov and his team (The Leibniz Institute for Solid State and Materials Research, Dresden, Germany) for research conducted via mass-spectrometer MALDI-TOF Bruker BIFLEX TM III.