Precise synthesis of well-defined electron conducting and donor-acceptor semiconducting copolymers for organic electronics

本项目旨在开发链增长催化剂转移缩聚方法，用于制备定义明确的缺电子半导体聚合物，用于有机电子器件（例如，太阳能电池和场效应晶体管）。目前用于制备半导体聚合物的主要分步生长方法不允许直接控制分子量、多分散性、端基和聚合物结构，这些因素极大地影响薄膜形态和分子取向。这些又是定义（经常限制）光电器件性能的因素。催化剂转移缩聚（CTP）是合成高分子和嵌段共聚物的一种独特方法。然而，可以通过CTP方法聚合的单体范围大多限于简单但富电子的单体。这些是不利的，因为性能最好的半导体聚合物通常由供体（D）和受体（A）单元构成，其聚合在很大程度上不发达。最近，Kiriy小组开发了可控地抑制这种D/A单体的方法，该项目旨在进一步发展这一成功。特别地，在该项目中，我们的目标是合成1）具有特定起始和末端基团的供体受体均聚物，所述特定起始和末端基团能够驱动聚合物的自组装和界面性质（例如共价结合到金属电极）和2）其中至少一个嵌段是DA共聚物的共辄嵌段共聚物。在第一阶段，该项目旨在通过改变Ni和Pd引发剂中配体的性质以及优化聚合条件以避免链终止来优化最佳n型聚合物P（NDI 2 ODT 2））（也称为N2200）之一的链生长合成。这一任务将通过详细的机理研究来实现。有了最佳的引发剂，在第二阶段，我们将制备具有特定起始/末端基团（如吡啶基）的聚合物，以提供聚合物链与金属电极的结合，并促进电荷注入过程。自组装（结合到电极，形态）和光电性能得到的嵌段共聚物也将进行研究。最后，最有前途的样品将被选择并交付给合作者，以进一步利用在光电器件。

This project aims at development of chain growth catalyst transfer polycondensation method for preparation of well defined electron deficient semiconducting polymers for their applications in organic electronic devices (e.g., solar cells and field effect transistors). Currently dominating step growth methods for preparation of semiconducting polymers do not allow a straightforward control over molecular weight, polydispersity, end groups and polymer architectures, factors which greatly influence thin film morphology and molecular orientation. These, in turn, are factors which define (frequently limit) performance of optoelectronic devices. Catalyst transfer polycondensations (CTPs) nowadays maturate as unique tool for the synthesis of well defined polymers and block copolymers. However, range of monomers which can be polymerized by CTP methods are mostly limited to simple, yet electron rich monomers. These are not favorable since the best performing semiconducting polymers are usually built of donor (D) and acceptor (A) units, the polymerization of which is, largely underdeveloped. Recently, the Kiriy group developed method to controllably polymerize such D/A monomer and this project aims at further development of this success. Particularly, in this project we aim at synthesis of 1) donor acceptor homopolymers with specific starting and end groups able to drive self assembly and interfacial properties of the polymers (such as to covalently bind to metal electrodes) and 2) al conjugated block copolymers in which at least one block is a DA copolymer. At the first stage, the project aims at optimization of the chain growth synthesis of one of the best n type polymer P(NDI2ODT2)) (also known as N2200) by varying nature of ligands in Ni and Pd initiators as well as optimization of polymerization conditions to avoid chain termination. This task will be realized through detailed mechanistic investigations. With the optimal initiator in hands, at the second stage, we will prepare polymers with specific start/end groups, such as pyridyl, to provide binding of polymer chains to metal electrodes and facilitate charge injection process. Self assembly (binding to electrodes, morphology) and optoelectronic properties of obtained block copolymers will be also investigated. Finally, most promising samples will be selected and delivered to collaborators for further utilization in optoelectronic devices.