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

Abstract

Force‐field and quantum‐chemical calculations are combined to model the packing of pentacene molecules at the atomic level on two polymer dielectric layers (poly(methyl methacrylate) (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. 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.

Origin of Electric Field Dependence of the Charge Mobility and Spatial Energy Correlations in C60-Based Field Effect Transistors

“…The dipolar disorder of the second C60 monolayer layer is ≈ 0.33σ BCB dip . We should note that these results perfectly agree with recent force-field and quantum-chemical calculations [38] which demonstrated that the electrostatic interactions introduce a significant energetic disorder in the pentacene OFET-semiconductor layer in contact with the polymer chains bearing static dipoles.…”

High-resolution spatial control of the threshold voltage of organic transistors by microcontact printing of alkyl and fluoroalkylphosphonic acid self-assembled monolayers

“…The fact that the mobility of the TFTs with the fluoroalkyl SAM is somewhat smaller than the mobility of the TFTs with the alkyl SAM is consistent with similar observations reported in the literature for various organic semiconductors [11][12][13][14]19,27]. One explanation that has been put forward by Mityashin et al based on results from a multiscale modeling study is related to the observation that the energetic disorder in the organic semiconductor layer is notably larger when the semiconductor is deposited onto a fluoroalkyl SAM, as opposed to an alkyl SAM [33], and that this larger energetic disorder leads to a smaller carrier mobility [34].…”

Enhanced Charge Transportation in Semiconducting Polymer/Insulating Polymer Composites: The Role of an Interpenetrating Bulk Interface

“…With respect to the neat P3BT sample, which might be regarded as P3BT nanowires surrounded by P3BT material itself, and in the P3BT/a‐P3BT composite where P3BT nanowires are surrounded by amorphous and still semiconductive a‐P3BT, no enhanced conductivity could be observed since the interfaces in these two cases are not able to provide a reduced activation energy for charge carrier transportation. Similar charge transportation characteristics, which are correlated with the semiconductor/insulator interface, have already been demonstrated in two‐dimensional field‐effect systems 34–40…”