Electronic disorder in crystalline organic semiconductor: the role of thermal motions modulating the transfer integrals in polyacenes

TL;DR

This study investigates how thermal motions in crystalline polyacenes cause electronic disorder by modulating transfer integrals, challenging existing models and highlighting dynamic disorder as a key factor limiting charge mobility.

Contribution

It combines molecular dynamics and quantum calculations to quantify thermal fluctuation effects on transfer integrals in organic semiconductors.

Findings

Transfer integral fluctuations are comparable to their average values.

Thermal motions significantly impact charge transport models.

Dynamic electronic disorder limits charge carrier mobility.

Abstract

The effect of thermal structural fluctuations on the modulation of the transfer integrals between close molecules is studied using a combination of molecular dynamics simulations and quantum chemical calculations of the transfer integral. We have found that the fluctuations of the transfer integrals are of the same order of magnitude of their average value for two common organic semiconductors an observation that puts into question the currently adopted models for charge transport in organic semiconductors and identifies in the dynamic electronic disorder the limiting factor for the charge carrier mobility.