高迁移率给体-受体型半导体共聚物的电荷传输研究

Semiconducting polymers have large application potentials on low-cost flexible electronics. Recently developed donor-acceptor (D-A) copolymers became the exciting materials presently in that they have exhibited exceptionally high carrier mobility (can be 10 cm2/Vs) despite that surprisingly low long-range structural order in their films. In this project, we will utilize the D-A copolymers of different molecular structures to construct the organic field-effect transistors (OFETs) and diode devices. The comprehensive electrical and spectroscopic investigations will be performed on carrier mobility, conductivity and electronic states of the polymer films, especially on charge transport behaviors of these novel polymers on the extreme conditions such as high charge density and high magnetic field. The studies will be intended to explore the mechanism of carrier transport and new physics of these D-A polymers. Furthermore, by taking various film growth strategies, we will engineer the film microstructures of the D-A polymers at different length scales and structural hierarchy, to investigate the effects of structural control on carrier transport behaviors. It is to unveil the key structural factors which dominate the performance parameters such as carrier mobility, as well as shed a new light on some of puzzles relevant to the structure-properties relationship for these materials. The efforts will also be made to search for the innovative solutions to achieve higher mobility of the D-A based OFETs. The research proposed in the project will be of high significance to get a deeper insight on the mechanism of carrier transport of organic semiconductors as well as to guide the materials design and develop high-performance organic electronic devices.

半导体聚合物在低成本柔性电子学上有突出的应用潜力。近年来出现的给体-受体(D-A)型共聚物显示出非常高的载流子迁移率(可达10 cm2/Vs)和奇特的薄膜结构，是当前的研究热点。本项目拟选择不同类型的D-A型共聚物制备场效应晶体管(OFET)和二极管等器件，采用综合的电学和谱学方法研究其载流子迁移率和电导等传输特性以及薄膜电子态，特别是在高电荷浓度和低温强磁场极端条件下的输运行为。探索其电荷传输机制，揭示其中的新现象和新规律。并运用不同的薄膜制备手段，在不同的结构尺度和结构层次上调控D-A共聚物薄膜微结构，研究各结构参数对电输运过程的影响，揭示控制载流子迁移率等性能参数的关键性结构因素，澄清一些至今仍困扰这类材料结构-性能研究的重要问题。通过薄膜结构的调控来探索提高OFET性能的有效途径。本项目研究将对深入认识有机半导体的电荷传输机制，指导新材料设计和发展高性能有机电子器件具有重要意义。

半导体聚合物在低成本柔性电子学上有突出的应用潜力。近年来出现的给体-受体(D-A)型共聚物显示出非常高的载流子迁移率(可达10 cm2/Vs)和奇特的薄膜结构，是当前的研究热点。本项目选择若干不同分子结构类型的新型D-A型共聚物半导体，通过发展新的有机薄膜生长策略，成功地实现了在不同的结构尺度和结构层次上调控其薄膜结构。结合综合性的薄膜微结构表征以及有机场效应晶体管（OFET）和二极管等器件的制备，系统地研究了D-A共聚物的分子结构和分子聚集态特性、分子取向以及薄膜织构、结构有序度和缺陷态等结构参数对器件载流子迁移率和电导等性能的影响。在此基础上发现了控制D-A型共聚物电荷传输特性的一些关键性结构因素，发展了提高其载流子迁移率的薄膜制备方法。此外还采用综合的电学和谱学方法，借助离子凝胶栅压调控和化学掺杂等手段，研究了D-A型共聚物在低温、高电荷浓度等极端条件下的输运行为和薄膜电子态。通过本项目的研究，对D-A型共聚物半导体的薄膜结构-性能关系和电荷传输机制有了新的理解，发现一些重要的新现象新规律以及提高OFET性能的有效途径。本项目研究对深入认识有机半导体的电荷传输机制，指导新材料设计和发展高性能有机电子器件具有重要意义。已发表SCI论文6篇，培养博士和硕士研究生共7名。