posted on 2016-06-17, 00:00authored byMicaela Matta, Fabio Biscarini, Francesco Zerbetto
Density
functional theory (DFT) calculations were used to assess the effect
of electric fields of varying magnitudes and directions on the molecular
structure of pentacene and other acenes. The aim is to understand
the response of acenes in organic field effect transistors, specifically
the structure of the first monolayer(s) deposited on the gate dielectric,
where the transversal electric field and the charge carrier density
are largest and charge transport occurs. Pentacene cycloaddition can
be enhanced by the application of electric fields oriented along the
direction of the forming bonds. Dimerization is likely to occur in
low-density, disordered domains, such as grain boundaries or terrace
edges. Together with other factors, dimerization could affect device
performance leading to an irreversible decrease of mobility due to
the creation of new trap states.