Electron spin resonance (ESR) study of Li-doped polyacenic semiconductive (PAS) material processed with heat treatment

The electron spin resonance (ESR) spectral change of Li-doped polyacenic semiconductive (PAS) materials has been examined before and after heat treatment to elucidate the decrease in the discharging amount of the heat-treated Li-doped PAS electrodes. Decrease in the peak-to-peak line width of the ESR lineshape has been observed for all the Li-doped PAS electrodes, indicating partial degradation of Li-dopants. These results strongly suggest the existence of two kinds of Li-dopants in the highly Li-doped PAS electrodes: heat-resistant and heat-labile ones.