Yang Xiaodi, Li Qikai, Shuai Zhigang
Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, 100080 Beijing, People's Republic of China. Graduate University of the Chinese Academy of Sciences, 100080 Beijing, People's Republic of China.
Nanotechnology. 2007 Oct 24;18(42):424029. doi: 10.1088/0957-4484/18/42/424029. Epub 2007 Sep 21.
Charge transport in molecular systems and biosystems can be different from that in inorganic, rigid semiconductors. The electron-nuclear motion couplings play an important role in the former case. We have developed a theoretical scheme to employ the Marcus electron transfer theory coupled with a direct diabatic dimer model and the Brownian diffusion assumption to predict the carrier mobility for molecular materials. For triphenylamine, a typical molecular transport material, the design strategies regarding the formation a cyclic or a linear dimer are evaluated from theoretical calculations for the carrier mobility. We made a comparison between the mobility and the electrical polarizability. It is found that in the case of triphenylamine dimer, these two quantities have different trends. The fact that the macrocycle possesses higher mobility but lower polarizability than the linear chain is due to the difference in the reorganization energy. The theoretical predicted temperature dependences are analysed within the hopping mechanism. The calculated room-temperature mobilities are in reasonable agreement with experimental values.
分子系统和生物系统中的电荷传输可能与无机刚性半导体中的电荷传输不同。电子-核运动耦合在前一种情况下起着重要作用。我们已经开发了一种理论方案，采用马库斯电子转移理论，结合直接非绝热二聚体模型和布朗扩散假设，来预测分子材料的载流子迁移率。对于典型的分子传输材料三苯胺，从载流子迁移率的理论计算出发，评估了形成环状或线性二聚体的设计策略。我们对迁移率和电极化率进行了比较。结果发现，在三苯胺二聚体的情况下，这两个量具有不同的趋势。大环比线性链具有更高的迁移率但更低的极化率这一事实，是由于重组能的差异。在跳跃机制内分析了理论预测的温度依赖性。计算得到的室温迁移率与实验值合理吻合。
