给-受型碳纳米带的设计合成及光电功能研究

In recent years, donor-acceptor copolymer materials have been widely synthesized and applied in the field of organic solar cells, because the connection by a C-C single bond between donor and acceptor subunits causes intramolecular charge-transfer in these materials, which improves the π electron delocalization to reduce the band gap, and broadens the absorption spectra. But there are still some problems, for example, the photoelectric conversion rate is not high because of the difficult purification and low electron mobility of these copolymer materials. The π electron delocalization is faster between the donor and acceptor subunits because the donor-acceptor carbon nanoribbons have a rigid carbon material structure which is connected by means of a benzene ring between the donor and acceptor subunits. Therefore, compared to the front donor-acceptor copolymer materials, the donor-acceptor carbon nanoribbons will have more wide absorption band and higher electron mobility, which are conducive to the application of carbon nanoribbons in the field of photoelectric functional devices. The research target of this project includes: the controllable preparation of three types of donor-acceptor carbon nanoribbons through organic synthesis procedure with atomic precision and the building of optoelectronic functional devices. It’s expected to get excellent optoelectronic functional materials through the research of this project, but there has been no report of such materials in the literature so far. Therefore, donor-acceptor carbon nanoribbons have important scientific significance and research value.

近年来，给-受型聚合物材料被广泛合成并应用于有机太阳能电池领域，是因为这些材料中给体、受体单元通过C-C单键相连会引起分子内电荷转移，有利于提高π电子的离域以降低能带隙，同时拓宽了吸收光谱。但是这些聚合物材料仍然面临聚合物难以纯化、电子迁移率太低而导致光电转化率不高等问题。给-受型碳纳米带具有刚性的碳材料结构，给、受体单元通过苯环相连，π电子可以更快地在给、受体单元间离域。因此，与前面给-受型聚合物材料相比，给-受型碳纳米带将具有更宽的吸收谱带和更高的电子迁移率，这些都有利于碳纳米带应用到光电功能器件领域。本项目通过有机合成方法从原子精度上可控制备三类给-受型碳纳米带，并构筑光电功能器件。通过本项目的研究，可望得到优异的光电功能材料，但是至今没有相关的文献报道。因此，给-受型碳纳米带具有重要的科学意义和研究价值。

在有机光/电材料的研究领域，大量的研究工作集中在如何调节与有机分子结构密切相关的能级和能隙。首先，我们通过双溴三苯和PDI四硼酸之间的四重铃木偶联反应将平面苝二酰亚胺（PDI）掰弯形成碗状结构，从而降低了PDI的HOMO和LUMO能级，缩小了能隙，调整了PDI三重态能级，使这些碗状PDI能够发生单线态裂分。其次，Stone-Wales重排通常在极端条件下的富勒烯、碳纳米管和石墨烯中发生，然而，我们发现在三氟酸的帮助下，Stone-Wales重排能够在小分子中发生。利用Stone-Wales重排反应可以在SP2-杂化碳晶格中获得非六元环，并改变材料的能级，通过理论计算，探索了合理的重排路径。第三，单分子导电是突破纳米电子器件领域摩尔定律的一种有前途的方法。我们设计了一系列的σ-共轭（双）环硅烷来研究未知的单分子电导行为。我们首先报道了一种具有官能化双环[2.2.2]八硅烷的饱和硅基分子，该分子在其σ-共轭中表现出破坏性的量子干涉，并通过将硅-硅键锁定成重叠构象而产生长度小于一纳米的极绝缘分子。与环π共轭分子相比，σ-共轭（双）环硅烷的电导主要由一条通过分子的路径控制，并受沿着该路径的二面角影响。最后，我们探索了六苯并苯二酰亚胺（CDI）的新合成方法，并通过芳香亲核取代和Sonogashira偶联反应探索CDI的官能团功能化，CDI是合成给体-受体纳米带的潜在合成子。本课题获得了调控分子结构与光/电性能相互关系的重要策略。这些重要突破将有助于未来新型有机材料的研究。