Charge transport in organic molecular semiconductors from first principles: The bandlike hole mobility in a naphthalene crystal
Charge transport in organic molecular semiconductors from first principles: The bandlike hole mobility in a naphthalene crystal
复制标题
DOI：
10.1103/physrevb.97.115203
复制
发表时间：
2017-12
影响因子：
3.7
通讯作者：
Nien-En Lee;Jin-Jian Zhou;Luis A. Agapito;M. Bernardi
中科院分区：
文献类型：
--
作者：
Nien-En Lee;Jin-Jian Zhou;Luis A. Agapito;M. Bernardi
预测有机分子晶体中的电荷传输是出了名的挑战。有机半导体中载流子迁移率的计算主要是基于电荷跃迁的量子化学方法，这种方法很费力，而且精度不高。在从头算能带理论框架下，从第一性原理出发，计算了萘晶体的电子-声子散射和声子限制空穴迁移率。我们的计算结合了GW电子能带结构、从头算电子-声子散射和玻耳兹曼输运方程。在100-300K温度范围内，计算得到的空穴迁移率与实验符合得很好，可以很好地预测空穴迁移率随温度的变化关系。结果表明，尽管分子内声子与空穴具有最强的耦合，但分子间声子与空穴之间的散射对迁移率有调节作用。我们重新审视了通常认为只有刚性分子运动才会影响有机分子晶体中的载流子动力学的观点。我们的论文为计算有机晶体中的电荷输运提供了一个定量和严格的框架，是向协调能带理论和载流子跳跃计算方法迈出的第一步。
Predicting charge transport in organic molecular crystals is notoriously challenging. Carrier mobility calculations in organic semiconductors are dominated by quantum chemistry methods based on charge hopping, which are laborious and only moderately accurate. We compute from first principles the electron-phonon scattering and the phonon-limited hole mobility of naphthalene crystal in the framework of ab initio band theory. Our calculations combine GW electronic bandstructures, ab initio electron-phonon scattering, and the Boltzmann transport equation. The calculated hole mobility is in very good agreement with experiment between 100 – 300 K, and we can predict its temperature dependence with high accuracy. We show that scattering between intermolecular phonons and holes regulates the mobility, though intramolecular phonons possess the strongest coupling with holes. We revisit the common belief that only rigid molecular motions affect carrier dynamics in organic molecular crystals. Our paper provides a quantitative and rigorous framework to compute charge transport in organic crystals and is a first step toward reconciling band theory and carrier hopping computational methods.