Interface properties and electronic structure of new organic low band gap materials

低能带隙聚合物是有机太阳能电池、发光二极管等光电器件中有机活性层的理想材料。这些材料在器件中的性能受到其薄膜形态和自组织能力的强烈影响。在第一个资助期内已经表明，（额外的）烷基噻吩部分可以显著改善LBG聚合物薄膜的成膜性能。本论文的第一个目标是系统研究在LBG聚合物结构中引入不同取代方式的噻吩基间隔单元对聚合物电子性质和自组织能力的影响。该合作项目的第二个重点是合成和表征新的二酮基吡咯并吡咯（DPP）为基础的给体-受体共聚物，具有不同程度的adderization。我们将研究平坦化/梯状化的程度如何影响薄膜的有序性和电子性质。薄膜和界面的实验研究将使用各种互补的光谱和显微技术进行，这些技术将提供有关薄膜（界面）电子结构和组织的广泛而详细的信息。除了原子力和电子显微镜，还包括光电发射和各种光谱学。

Low band gap (LBG) polymers are promising candidates for activeorganic layers in opto-electronic devices, such as organic solar cellsor light emitting diodes. The properties of these materials in devicesare strongly influenced by their morphology and ability for selforganizationin thin-films. It was already shown within the first fundingperiod that (additional) alkyl-thiophene moieties can improve distinctlyfilm forming properties in thin films of LBG polymers. A systematicinvestigation of the influence of the introduction of thienylene spacerunits with different substitution pattern in LBG polymer structures onboth electronic properties and the ability for self-organization is thefirst goal of this proposal. The second focus of the joint project is thesynthesis and characterization of new diketopyrrolopyrrole (DPP)-based donor-acceptor co-polymers with a varying degree ofladderization. We will investigate how the degree ofplanarization/ladderization influences the ordering and electronicproperties in thin films. The experimental investigations of thin filmsand interfaces will be carried out using a variety of complementaryspectroscopic and microscopic techniques that shall provide wide anddetailed information on both (interfacial) electronic structure andorganization in thin films. That includes photoemission and variousoptical spectroscopies in addition to atomic force and electronmicroscopy.