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.

中文翻译：

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分析外部和内部无序以了解n型有机半导体中的带状传输

众所周知，有机半导体中的电荷传输对内部和外部无序（即，与介电层的相互作用有关）的存在极为敏感，特别是对于n型材料而言。内部动态紊乱源于分子间传递积分和弱相互作用的范德华固体中分子间转移积分和（分子）位能的巨大热波动，并导致电荷载流子的瞬态局部化。驱动瞬态本地化的分子振动通常在低频（<几百cm ^-1），因此很难通过实验对其进行评估。迄今为止，这阻止了明确的分子设计规则的确定，以控制和减少动态紊乱。另外，无序也可以是外部的，由栅极绝缘体的介电特性控制。本文报道了结合温度相关的非弹性中子散射和光电子光谱学对两种紧密相关的n型分子有机半导体中的电荷传输进行的全面研究，并通过电学测量，理论和模拟证实了这一点。提供了明确的证据，即席分子设计使电子载流子从内部和外部无序中解脱出来，最终达到带状电子传输。