N型电学掺杂剂作用机理及其在有机光电器件中的应用研究

The electrical doping of organic semiconductor is an important scientific issue which is worth intensive investigation. The aim of this project to systematically investigate the route of synthesis of the N-type dopants based on novel transition metal complexes. Via the synthesis and application of the N-type electrical dopants, we are able to assess the doping mechanism of different transition metal complexes and study the application of these dopants in organic light-emitting diodes and organic photovoltaic devices. It is the relationship of the synthesis route of the N-type dopants, ionisation potential and the position of the elements of transition metals in the periodic table of the elements that will be fully explored in this research. The rule of the synthesis of the highly efficient N-type electrical dopants will be predicted accordingly. Based on the Seebeck effect, the type of the electrical doping can be readily verified. By doping these materials into the electron transport materials, we can obtain the correlation of the doping efficiency, carrier concentration and mobility with the N-type dopants. According to the energy level relationship and charge transfer mechanism, the reaction during the N-type doping process will be unveiled. We will specify the compatibility of the N-type dopants and the electron transport materials. Finally, these dopants will be applied in the research of organic light-emitting diodes and organic photovoltaic devices and the performance will be compared systematically. Throughout this project, we will further correlate the reduction ability of a series of transition metal complexes with the doping effect. It will be a good theoretical and experimetal basis which potentially leads to new pathways of developing new kind of materials and devices in this interdisciplinary study.

有机半导体材料的电学掺杂是有机半导体研究中值得深入研究的重要科学问题之一。本项目旨在利用有机半导体的电学掺杂剂合成和应用技术，系统地研究基于过渡金属配合物的的N型电学掺杂剂的合成路线，探索不同过渡金属配合物的掺杂机理及其在有机电致发光器件和有机光伏器件中的应用。通过研究过渡金属在元素周期表中位置与N型电学掺杂剂的合成方法、电离能大小关系，摸索高效率N型电学掺杂剂的一般合成规律。根据Seebeck效应，验证电学掺杂剂的掺杂类型，并研究其在电子传输材料中的掺杂效率及其对载流子浓度和迁移率大小变化的影响。根据能级关系和电荷转移机制，明确有机半导体N型掺杂涉及的反应机制，摸索N型掺杂剂与电子传输材料的最佳配伍关系。最后研究N型电学掺杂层对有机电致发光器件和有机光伏器件性能的影响，总结不同还原性的材料作为有机半导体N型电学掺杂剂的一般规律，为开发新材料和新器件结构这一交叉学科研究奠定理论和实验基础。

有机半导体的N型电学掺杂可以产生可“自由移动”的电子，提高载流子的密度，同时提高传输层的电导率，对于降低电子从电极到电子注入层或传输层或有源层都会起到有益的作用。常见的适合有机半导体的高效N型电学掺杂剂对环境的要求十分苛刻，本研究针对这一特点，利用无水无氧的手套箱环境，合成了一系列具有较高还原性的基于过渡金属配合物的电学掺杂剂，并将其进行相应的器件应用，发现这类材料可以大幅降低有机电致发光器件的工作电压，起到了电学掺杂的作用。针对基于过渡金属配合物对水氧及其敏感的特点，本研究也摸索出一套新的发展N型电学掺杂结构的方法，包括设计和合成了一系列掺杂剂前驱体，利用其在真空蒸镀的过程分解为有效的电学掺杂剂；进一步地，本项目还开发出一系列具有N型自掺杂效应的电学材料，采用溶液加工的工艺，制备了一系列有机电致发光器件和有机光伏器件，分析了自掺杂体系的材料结构与器件性能的关系，摸索出发展N型电学掺杂材料的一些规律。综上，藉由本研究开展，推动了N型电学材料的研究体系和器件应用开发，达到了项目实施的意义，为下一步开发新的材料体系，研究有机半导体的电学掺杂现象奠定了基础。