Design, synthesis, and properties of self-organizing dyes

我们的研究小组开发了基于自组织染料和其他化合物（如液晶）的新材料，以及基于聚合物和纳米颗粒及其复合材料的纳米结构材料。天然和合成染料在我们的环境中无处不在，对特定技术性能改进的新染料的需求不断增加。在本提案中，我们将开发有机染料的新设计标准(i)自组织成柱状堆叠和（ii）形成定义结构的单分子厚膜（单层）。所有提议的项目都强调对有机电子的潜在应用至关重要的特性，尽管我们意识到该领域的发展有各种各样的应用，从着色剂和荧光探针到基于盘状液晶的高压润滑剂。芳香染料柱状堆叠具有各向异性有机半导体的功能，其电荷输运性能优于目前使用的有机半导体。然而，柱状相作为有机半导体在电子器件中的应用已经停滞不前，因为它们的加工对于主要由印刷技术制造的工业目标低成本器件来说过于复杂。我们确定了横向侧链的附着，这是几乎所有已知柱状相共同的设计概念，是其作为商业器件应用的有机半导体主要缺陷的根本原因。第一个项目的主要目标是开发基于不含侧链的柱状相的有机半导体。具体来说，我们将针对块状异质结有机太阳能电池中有机半导体所需的材料特性，因为我们相信染料的柱状相比传统的有机半导体具有一些独特的优势，因为它们的自组织特性应该有助于所需纳米结构的形成。太阳能电池的制造和测试将与学术和工业伙伴合作进行。分子在电极之间的垂直排列形成柱状结构对于具有半导体特性的有机器件是必不可少的，因为电荷导电性只有沿着柱状堆叠才高。然而，对于有机发光和光伏器件来说，这种封装母题尤其难以实现。我们提出的第二组项目通过制备不溶性的单分子染料薄膜直接解决了这个问题，这些染料薄膜表现出染料分子相对于底物的平面取向。这些薄膜有望作为目前无法在衬底上垂直排列的许多柱状相的第一垂直排列层。所提出的方法进一步推进了我们最近在薄膜中染料分子的排列以及它们的交联到热和化学上坚固的薄膜上的技术。然而，具有平面取向的交联染料的应用并不局限于它们用作柱状相的对准层。我们的长期目标包括应用这些薄膜作为电极表面化学和电子修饰的坚固涂层，以及基于这种定向和交联方法开发二维共轭薄膜和三维共轭染料体材料。特别是修饰电极表面的表征，这是优化无机电极材料和有机半导体之间界面的重要选择，将需要与专家组合作，并提供极好的机会来加强HQP的培训。

Our research group develops new materials based on self-organizing dyes and other compounds (e.g. liquid crystals), and nanostructured materials based on polymers and nanoparticles as well as their composites. Natural and synthetic dyes are ubiquitous in our environment and new dyes with improved properties for specific technologies are constantly in demand. In this proposal we shall develop new design criteria for organic dyes that (i) self-organize into columnar stacks and (ii) form one molecule thick films (mono-layers) of defined structure. All proposed projects emphasize properties that are critical for potential applications in organic electronics, though we are aware that developments in this area have a diverse range of applications from colorants and fluorescent probes to discotic liquid crystal based high pressure lubricants. It is well established that columnar stacks of aromatic dyes function as anisotropic organic semiconductors that have achieved charge transport properties superior to presently used organic semiconductors. However, the utilization of columnar phases as organic semiconductors in electronic devices has stalled because their processing is too complex for industrially targeted low cost devices that are mainly manufactured by printing technologies. We identified the attachment of lateral side-chains, a design concept common to almost all known columnar phases, as the root cause for their main deficiencies as organic semiconductors for commercial device applications.The main objective of the first project is the development of organic semiconductors based on columnar phases that do not contain lateral side-chains. Specifically, we will target materials properties required for organic semiconductors in bulk-heterojunction organic solar cells as we believe columnar phases of dyes have some unique advantages over conventional organic semiconductors due to their self-organizing properties that should aid the formation of the required nanostructures. Fabrication and testing of solar cells will be conducted in collaboration with both academic and industrial partners.The vertical alignment of molecules between the electrodes to form columnar structures is essential for organic devices with semiconductor properties since charge conduction is only high along the columnar stacks. Yet this packing motif, which is necessary for organic light emitting and photovoltaic devices, is particularly difficult to achieve. Our second set of proposed projects directly addresses this problem through the preparation of insoluble, unimolecular dye films that exhibit flat-on orientations of the dye molecules with regard to the substrate. These films are expected to function as the first vertical alignment layer for the many columnar phases that presently cannot be aligned vertically on substrates. The proposed approaches further advance technology we recently developed on the alignment of dye molecules in thin films and their cross-linking to thermally and chemically robust films.Applications of cross-linked dyes with flat-on orientation, however, are not limited to their use as alignment layer for columnar phases. Our long term objectives include the application of these films as robust coatings for chemical and electronic modification of electrode surfaces as well as the development of 2-dimensionally conjugated films and 3-dimensionally conjugated bulk materials of dyes based on this alignment and cross-linking methodology. Especially the characterization of modified electrode surfaces, an important option for the optimization of interfaces between inorganic electrode materials and organic semiconductors, will require collaborations with expert groups and afford excellent opportunities to enhance the training of HQP.