Analysis of External and Internal Disorder to Understand Band‐Like Transport in n‐Type Organic Semiconductors

Publication date: 25 Feb 2021

JournalSource: OPENALEXOpenAlex type: articleOpen Access
Authors: Marc‐Antoine Stoeckel, Yoann Olivier, Marco Gobbi, Dmytro Dudenko, Vincent Lemaur, Mohamed Zbiri, Anne A. Y. Guilbert, Gabriele D’Avino, Fabiola Liscio, Andrea Migliori, Luca Ortolani, Nicola Demitri, Xin Jin, Young‐Gyun Jeong, Andrea Liscio, M Nardi, Luca Pasquali, Luca Razzari, David Beljonne, Paolo Samorı́, Emanuele Orgiu

Abstract Charge transport in organic semiconductors is notoriously extremely sensitive to the presence of disorder, both internal and external (i.e., related to interactions with the dielectric layer), especially for n‐type materials. Internal dynamic disorder stems from large thermal fluctuations both in intermolecular transfer integrals and (molecular) site energies in weakly interacting van der Waals solids and sources transient localization of the charge carriers. The molecular vibrations that drive transient localization typically operate at low‐frequency (<a‐few‐hundred cm −1 ), which makes it difficult to assess them experimentally. Hitherto, this has prevented the identification of clear molecular design rules to control and reduce dynamic disorder. In addition, the disorder can also be external, being controlled by the gate insulator dielectric properties. Here a comprehensive study of charge transport in two closely related n‐type molecular organic semiconductors using a combination of temperature‐dependent inelastic neutron scattering and photoelectron spectroscopy corroborated by electrical measurements, theory, and simulations is reported. Unambiguous evidence that ad hoc molecular design enables the electron charge carriers to be freed from both internal and external disorder to ultimately reach band‐like electron transport is provided.

Origin
Advanced Materials
Volume
33
Issue
13
Pages
e2007870
Cited by
39
Legacy ID
ff385bfa992e5d44b2ee7c50e99bea9c
Biblio references
Volume: 33 Issue: 13 Pages: 2007870