Optical properties of a soluble conducting polymer, perfluoroalkylated
poly(diphenylacetylene) (PFPDPA) were clarified. The band-gap energy
was evaluated to be about 2.7 eV. Relatively strong fluorescence was o
bserved in PFPDPA, while poly(diphenylacetylene) (PDPA) is considered
to be a conducting polymer with a degenerated ground state in which a
soliton is considered to play an important role. A light-emitting diod
e (LED) with In-Mg/PFPDPA/indium-tin-oxide (ITO) configuration was fab
ricated and green light emission was observed.