Highly Segregated Lamello-Columnar Mesophase Organizations and Fast Charge Carrier Mobility in New Discotic Donor-Acceptor Triads.
Highly Segregated Lamello-Columnar Mesophase Organizations and Fast Charge Carrier Mobility in New Discotic Donor-Acceptor Triads.
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DOI：
10.1002/chem.201500889
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发表时间：
2015-07
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通讯作者：
K. Zhao;Ling-Ling An-Ling;Xiao-Bo Zhang;Wenhao Yu;P. Hu;Bi-qin Wang;Jing Xu;Q. Zeng;H. Monobe;Y. Shimizu;B. Heinrich;B. Donnio
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作者：
K. Zhao;Ling-Ling An-Ling;Xiao-Bo Zhang;Wenhao Yu;P. Hu;Bi-qin Wang;Jing Xu;Q. Zeng;H. Monobe;Y. Shimizu;B. Heinrich;B. Donnio
通过Sonogashira偶联和环合反应，合成了四种新的基于二硫代和亚芳基介晶的给体-受体三元组（D-A-D）。该三元组家族由两个侧接侧挂的苯并菲介晶组成，充当给电子基团（D），通过短的亲脂性间隔基分别横向连接到中心的二萘嵌苯二酰亚胺（PI）、苯并[ghi]二萘嵌苯二酰亚胺（BI）或晕苯二酰亚胺（Cl）分子单元，起到电子受体（A）的作用。所有D-A-D三元组自组织形成具有高度隔离的供体-受体（D-A）异质结组织的层状-柱状倾斜中间相，从而实现有效的分子自分选。该结构包括在规则交替的两个中断行的苯并菲列和一个连续行的二亚胺物种。高分辨率的STM图像表明，PI-TP 2形成稳定的二维自组装纳米结构，具有不同程度的规则性，而其他三元组不能自组织成有序的结构。通过在200 °C下在中间相中的飞行时间测量的CI-TP 2的电子传输迁移率比空穴迁移率高一个数量级。通过这种特定的分子设计思想，我们首次在分子水平上实现并证明了所谓的p-n异质结，其中富电子的苯并菲柱充当空穴瞬态通道，而冠二酰亚胺堆叠形成电子传输通道。
Four new donor-acceptor triads (D-A-D) based on discotic and arylene mesogens have been synthesized by using Sonogashira coupling and cyclization reactions. This family of triads consists of two side-on pending triphenylene mesogens, acting as the electron-donating groups (D), laterally connected through short lipophilic spacers to a central perylenediimide (PI), benzo[ghi]perylenediimide (BI), or coronenediimide (CI) molecular unit, respectively, playing the role of the electron acceptor (A). All D-A-D triads self-organize to form a lamello-columnar oblique mesophase, with a highly segregated donor-acceptor (D-A) heterojunction organization, consequent to efficient molecular self-sorting. The structure consists in the regular alternation of two disrupted rows of triphenylene columns and a continuous row of diimine species. High-resolution STM images demonstrate that PI-TP2 forms stable 2D self-assembly nanostructures with some various degrees of regularity, whereas the other triads do not self-organize into ordered architectures. The electron-transport mobility of CI-TP2, measured by time-of-flight at 200 °C in the mesophase, is one order of magnitude higher than the hole mobility. By means of this specific molecular designing idea, we realized and demonstrated for the first time the so-called p-n heterojunction at the molecular level in which the electron-rich triphenylene columns act as the hole transient pathways, and the coronenediimide stacks form the electron-transport channels.