Phase dependence of hole mobilities in dibenzo-tetrathiafulvalene crystal: A first-principles study

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• 作者：Guangjun Nan^a ; ^{gjnan@hit.edu.cn} ; Zesheng Li^a ; ^b ; ^c ; ^{zeshengli@hit.edu.cn}
• 关键词：Organic semiconductor ; Dibenzo-tetrathiafulvalene ; Marcus charge transfer rate ; Charge mobility ; Density functional theory
• 刊名：Organic Electronics
• 出版年：2012
• 期刊代码：137_15661199
• 类别：et
• 出版时间：July, 2012
• 卷：13
• 期：7
• 页码：1229-1236
• 文件大小：954 K

摘要

The organic semiconductor dibenzo-tetrathiafulvalene (DBTTF) has presented different polymorphs in solid packing, but the structure-property relationship is little clarified in the literature which is important for the design of high-performance organic semiconductors. In this study, the charge transport in DBTTF crystals for the 伪 phase and 尾 phase is investigated from the first-principles calculations and the Marcus charge transfer theory. The one-, two- and three-dimensional mobilities are obtained simultaneously from a set of identical trajectories with an improved random walk technique. It is found that the 伪-phase crystal presents a smaller three-dimensional mobility than that in the 尾-phase crystal although the mobility is much large along the c axis in the 伪-phase crystal. This is attributed to that the electronic couplings are mainly confined within the c axis for the 伪-DBTTF while the electronic couplings are more uniform in the three-dimensional space for the 尾-DBTTF which thus provides more transport pathways for the charge transport. As a result, the 尾-DBTTF may have a larger potential for practical applications in organic electronics.