硼氮掺杂的大共轭体系及其在有机电子器件中的应用

Large π-conjugated systems with high rigidity and planarity are a hot topic in the study of organic electronic materials due to their outstanding optoelectronic properties. Incorporation of B-N bond with the bipolar character into a large π-conjugated system has, in recent years, been proved to be an effective strategy for tuning the optoelectronic properties of the conjugated system, so that it is efficient for realizing novel materials. However, the study on BN-doped materials featuring B-N bonds is still in the neonatal stage, and further exploration on the electronic application of this type of materials is urgently needed. In the reported BN-doped systems, the doping ratio between B and N atoms is usually limited to 1:1, and the doped systems are usually polycyclic aromatics. In this project, we will develop novel BN-doped large π-conjugated systems using two strategies, i.e. tuning the doping ratio between B and N atoms and altering the structural feature of the doped system, in order to realize novel material systems for light-emitting diodes, solar cells and field-effect transistors. The functional groups containing B-N bonds will be utilized to increase the doping ratio of N atoms relative to B atoms. It is expected that the doping of more electron-rich N atoms benefits the hole injection and transport, as well as the device performance. In addition, the B-N bond will be used to construct BN-doped quinoidal structures with a large π-conjugated skeleton and a low bandgap. The application of these novel quinoidal systems in organic electronic devices, especially the photovoltaic devices, will be explored.

具有大的共轭骨架、较强刚性、较好平面性的有机化合物因其优异的光电性能成为有机电子材料领域的研究热点之一。近年来的研究表明，将具有偶极特征的B-N键引入刚性大共轭体系实现BN掺杂是调节体系光电性能、构建新型材料的一种有效手段。然而，相关研究方兴未艾，BN掺杂体系的光电应用亟待进一步探索。目前报道的BN掺杂体系中B、N原子的掺杂比例通常局限于1:1，且掺杂体系多为稠环芳香体系。针对这一现状，本项目拟从B、N原子的掺杂比例和BN掺杂体系的结构特征两方面开展工作，构建新颖的BN掺杂大共轭体系，以期实现新型的电致发光、太阳能电池及场效应晶体管材料。我们将利用含有B-N键的基团提高BN掺杂稠环体系中N原子的掺杂比例，以提高材料的空穴注入、空穴传输等性质和材料的器件性能。同时，我们将利用B-N键构筑具有较低能隙的醌式大共轭体系，并探索这类新型材料在光电器件中，尤其是太阳能电池中的应用。

有机电子材料因其在显示、照明、光伏电池、电子元件等领域的应用得到了广泛关注。有机共轭分子是有机电子材料研究的基础。为了拓展材料结构，调节和改善材料性能，一种重要手段是将杂原子引入共轭体系。由于杂原子的多样性、杂原子数量的可控性、引入位点的可选择性以及杂原子对分子间非共价作用的显著影响，向共轭体系中引入杂原子为材料开发提供了无限可能。近年来，将硼、氮原子引入共轭体系得到了较多的关注，成为高性能材料开发的一种有效手段。本项目致力于开发含有硼、氮杂原子的大共轭体系，以期实现具有新颖结构和优良性能的有机电子材料。我们探索了多种类型的含有硼、氮原子的共轭体系的构建，不仅调节了硼、氮原子的比例和引入位点，也尝试了利用硼、氮原子构建新颖的醌式体系。为了深入了解材料性能，我们对所开发材料进行了热力学、电化学、光物理等多方面的表征。对于所开发的一些具有优异发光性能的材料，我们开展了电致发光器件的制备和优化，得到了高性能的器件，其中蓝光和绿光电致发光器件的外量子效率都超过了20%，并且都具有较高的色纯度，红光器件也具有超过10%的外量子效率。同时，我们也尝试了一些材料在场效应晶体管领域的应用。通过对比研究，我们加深了对材料结构与性能之间关系的理解，为今后相关材料的进一步开发和改进奠定了基础。本项目的实施有助于更多高性能的有机电子材料的实现。