Structural and electronic transitions in potassium doped pentacene

• We calculate the ground state geometrical structure of potassium-intercalated pentacene lattices using molecular mechanics and the density-functional theory. Both methods result in a structural phase transition in going from the pristine form to the intercalated state with one potassium ion per pentacene molecule. The phase transition is characterized by a sliding of adjacent pentacene molecules relative to each other. The electronic properties of this phase is studied with the density-functional theory. As a result of the geometrical changes, the - overlap in the direction perpendicular to the molecular planes of the layered pristine pentacene structure increases substantially and many of the electronic bands show strong dispersion in this direction. The Fermi energy of the doped phase appears in the middle of the conduction band where the density of states is maximum. The bandwidth of the conduction band is 0.7  eV.

Nyckelord

potassium

organic semiconductors

density functional theory

solid-state phase transformations

conduction bands

Fermi level

electronic density of states

ground states

NATURAL SCIENCES

NATURVETENSKAP

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)