Thin Films of n-Si/Poly-(CH₃)₃Si-Cyclooctatetraene: Conducting-Polymer Solar Cells and Layered Structures

The optical and electronic properties of thin films of the solution-processible polymer poly-(CH₃)₃Si-cyclooctatetraene are presented. This conjugated polymer is based on a polyacetylene backbone with (CH₃)3Si side groups. Thin transparent films have been cast onto n-doped silicon (n-Si) substrates and doped with iodine to form surface-barrier solar cells. The devices produce photovoltages that are at the theoretical limit and that are much greater than can be obtained from n-Si contacts with conventional metals. Two methods for forming layered polymeric materials, one involving the spin-coating of preformed polymers and the other comprising the sequential polymerization of different monomers, are also described. An organic polymer analog of a metal/insulator/metal capacitor has been constructed with the latter method.