Organic Semiconductors: Impact of Disorder at Different Timescales

• Published in: Chemphyschem Vol. 11; no. 10; pp. 2067 - 2074
• Main Authors: McMahon, David P., Troisi, Alessandro
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 12.07.2010; WILEY‐VCH Verlag; Wiley
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity of specific materials; disorder; Electronic transport in condensed matter; Exact sciences and technology; molecular dynamics; organic electronics; Physics; polymers; Polymers; organic compounds (including organic semiconductors); quantum chemistry; Molecular dynamics method; Molecular crystals; quantum chemistry; Semicrystalline polymer; organic electronics; molecular dynamics; Liquid crystals; disorder; Organic semiconductors; Wave functions; Transport processes; Property structure relationship; polymers; Carrier mobility; Classical theory; Master equations; Quantum theory
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201000182

The charge transport in organic materials, from molecular crystals to polymers, is determined by their degree of disorder. The dynamic disorder in ideal molecular crystals at room temperature and the static disorder in disordered polymers are just two limiting cases of the timescale of the fluctuations in the electronic Hamiltonian caused by nuclear motions. In fact, a very large number of important materials (e.g. liquid crystalline semiconductors) are actually in an intermediate regime where the disorder is neither purely static nor purely dynamic. This Minireview discusses the recent contribution of computational chemistry (molecular dynamics and quantum chemistry) to the characterization of these transport regimes and outlines the theoretical methods that can be used to relate the system characteristics to the measurable mobility. Disorder in organic semiconductors evolves over different timescales depending on the material. The dynamic disorder in ideal molecular crystals at room temperature and the static disorder in disordered polymers are two limiting cases of the timescale of the fluctuations caused by nuclear motions (see figure). Liquid crystalline semiconductors fall within an intermediate regime where the disorder is neither purely static nor purely dynamic.