Modeling Polymer Dielectrics/Pentacene Interfaces: On the Role of Electrostatic Energy Disorder on Charge Carrier Mobility

Force-field and quantum-chemical calculations have been combined to model at the atomistic level the packing of pentacene molecules on two polymer dielectric layers (PMMA versus polystyrene – PS) widely used in field-effect transistors and to assess the impact of electrostatic interactions at the interface on the charge mobility values in the pentacene layers, respectively. The results show unambiguously that the electrostatic interactions introduce a significant energetic disorder in the pentacene layer in contact with the polymer chains; a drop in the hole mobility by a factor of 5 is predicted with PS chains while a factor of 60 is obtained for PMMA due to the presence of polar carbonyl groups.