On the Inapplicability of Electron-Hopping Models for the Organic Semiconductor Phenyl-C61-butyric Acid Methyl Ester (PCBM)
On the Inapplicability of Electron-Hopping Models for the Organic Semiconductor Phenyl-C61-butyric Acid Methyl Ester (PCBM)
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DOI：
10.1021/jz400227c
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发表时间：
2013-03-21
影响因子：
5.7
通讯作者：
Blumberger, Jochen
中科院分区：
文献类型：
--
作者：
Gajdos, Fruzsina;Oberhofer, Harald;Blumberger, Jochen
苯基-C61-丁酸甲酯（PCBM）是有机光伏电池中最受欢迎的半导体之一，但其微晶结构中的电子传输机制及其优选的堆积结构仍不清楚。在这里，我们使用密度泛函理论来计算可用实验和模型晶体结构的电子耦合矩阵元、重组能和活化能。我们发现，从一个富勒烯到另一个多余的电子跳跃的图片不适用于任何的结晶相，使传统的速率方程不合适。我们还发现，结合能增加的顺序体心立方<六方<简单立方<单斜<三斜，独立的色散校正的类型。我们的研究结果表明，耦合的电子-离子动力学需要明确解决，以获得一个现实的描述在这种材料中的电荷转移。
Phenyl-C61-butyric acid methyl ester (PCBM) is one of the most popular semiconductors in organic photovoltaic cells, but the electron-transport mechanism in the microcrystalline domains of this material as well as its preferred packing structure remain unclear. Here we use density functional theory to calculate electronic-coupling matrix elements, reorganization energies, and activation energies for available experimental and model crystal structures. We find that the picture of an excess electron hopping from one fullerene to another does not apply for any of the crystalline phases, rendering traditional rate equations inappropriate. We also find that the cohesive energy increases in the order body-centered-cubic < hexagonal < simple cubic < monoclinic < triclinic, independently of the type of dispersion correction used. Our results indicate that the coupled electron-ion dynamics needs to be solved explicitly to obtain a realistic description of charge transfer in this material.