Electron-spin-resonance studies of porous polyacenic semiconductive materials

Abstract

Electron-spin-resonance (ESR) studies of porous polyacenic semiconductive materials in the pristine and the heavily ${\mathrm{I}}_{2}$-doped regimes have been carried out. The measurement temperature has been varied from 15 K to room temperature. Two kinds of typical polyacenic semiconductive sample essentially prepared by pyrolysis at 600 \ifmmode^\circ\else\textdegree\fi{}C and 700 \ifmmode^\circ\else\textdegree\fi{}C of phenol-formaldehyde resin were selected for the ESR measurements. In particular, the temperature-dependent behavior of the peak-to-peak linewidth of the ESR line shape for all samples was discussed in detail, particularly in relation to the hopping behavior of unpaired spins.