Dependence of optical properties of mono- and di-substituted polyacetylenes on substituent

We have studied the optical and photovoltaic properties in thin films of novel types of polyacetylene derivatives such as monosubstituted polyacetylenes and disubstituted polyacetylenes. Poly(o-trimethylsilylphenylacetylene) (PPA-oSiMe(3)) and poly(1-phenyl-2-p-n-butylphenylacetylene) (PDPA-nBu) have demonstorated their unique optical characteristics, and we found that the heterostructure photovoltaic cell of PPA-oSiMe(3)/fullerene had larger photosensitivity than that of PDPA-nBu/fullerene. The interactions between polyacetylene derivatives and fullerene at the interface have been investigated, and the photocurrent processes have been discussed by taking the electronic states into consideration.