有机-无机杂化纳米材料中的电子转移及机制调控

Organic-inorganic hybrid nanomaterials are of crucial importance for the application in the fields of light-to-electric conversion and photon detection. However, the interfacial structure and its influence on the fundamental electron transfer processes in the hybrid systems is still elusive. This project devotes to understanding the basic framework of photoinduced electron transfer in hybrid nanomaterials. Donor-acceptor copolymers and typical inorganic semiconducting nanocrystals are used for the architecture construction of the bandgap-variable, energy-level tunable hybrid model systems, acting as electron donor and electron acceptor, respectively. Femtosecond time-resolved absorption spectroscopy is utilized to monitor interfacial electron-transfer kinetics in these systems, especially the time evolution of the charge transfer exciton (CT exciton) dissociation/recombination when applying an additional electric field to the composites. We try to summarize and eludicate the interactional influence between the material selection, the interfacial structure, energy-level alignment and electron transfer dynamics. Moreover, surface modification of inorganic nanocrystal will be conducted using n-type arylene diimide deravatives(such as naphthalene diimide, perylene diimide) and the obtained three-phase systems are photophysically characterized with an enphasis on the role of the intermediate modificant. With the aid of device performance measurement of hybrid photovoltaic systems, the relationship between material composition, interfacial structure, fundamental physical processes and ultimate device action is to be explored, providing data basis and important gudiance for the development of novel principle for high-efficiency organic-inorganic hybrid systems.

有机-无机杂化纳米材料在光电转换和光检测领域中有着非常重要的应用。但是，杂化材料的界面形成机制及其对电子转移过程的影响规律还远不清楚。本课题将以电子给体-受体型聚合物与典型无机半导体作为电子给体和电子受体材料，构筑带隙不同、能级结构可控的模型杂化体系，利用时间分辨吸收光谱考察杂化体系中界面电子转移动力学，重点关注电场调控下电荷转移激子(CT exciton)解离/复合的动态演化行为，总结和揭示给体受体材料的选择对界面结构、能级排布以及电子转移过程的影响规律。进一步，用n型半导体对无机纳晶材料进行表面修饰，考察三元杂化体系中中间修饰层对聚合物与无机半导体间的电子转移的过程调控，结合杂化光伏器件的性能测试，探索材料组成、界面结构、微观物化过程和宏观器件效率之间的关联，为发展新原理、新机制指导高性能的杂化体系的构筑提供实验依据和数据基础。

有机-无机杂化纳米材料在光电转换和光检测领域中有着非常重要的应用。但是，杂化材料的界面形成机制及其对电子转移过程的影响规律还远不清楚。我们从有机给受体复合物的设计合成、无机纳晶的制备和电子转移动力学三方面入手开展研究，结合理论模拟，系统研究了分子结构、分子聚集对其微观电子转移行为及宏观光电性质的影响规律，为发展新原理、新机制指导高性能的杂化体系的构筑提供了可靠的实验依据和数据基础，也为下一步的光电应用提供了方向上的指引。在基金委的大力支持下，经过全体课题成员的共同努力，课题研究取得了一系列成果，实现了课题的研究目标。主要成果如下：（1）设计合成了一系列基于芳环骨架的有机给受体复合物，可与无机受体材料能级较好的匹配，通过键合或共混方式构筑杂化材料体系；（2）制备了异价掺杂无机纳晶、氧化锌微晶和石墨烯微米薄片等无机半导体材料，并可实现能级调控；（3）利用时间分辨光谱研究了杂化材料体系中的界面电子转移动力学，考察了电荷转移激子的解离/复合动态演化行为，制成原型器件并测试效率，阐明电子转移和宏观性能的关联机制。2014年以来，共发表SCI论文9篇，其中Angew. Chem. Int. Ed. 1篇，Adv. Mater. 1篇；申请人吴义室作为“有机光功能材料研究集体”成员之一荣获2016年度中国科学院杰出科技成就奖。