Abstract
We have measured the doping induced optical absorption in segmented polyacetylene, [CDH
y
]
x
, in which either 15% or approximately 27% sp
3
-bonded CDH units. These sp
3
defects, which can be called "conjugation-interrupting" defects have an average spacing considerably less than the length of a soliton. In order to introduce the charged soliton excitation, all samples were doped with iodine by in-situ vapor doping technique with various dopant levels. For a sample with 27% sp
3
hybridization, we have found a new broad band around 1.12 eV with relatively lower intensity for lower sp
3
. We assigned this band as an absorption due to the neutral solitons. The optical properties of deuterated polyacetylene with sp
3
defects including the comparison with ordinary polyacetylene, (CH)
x
, will be discussed.