分子内与分子间CT过程协同增强光电转换效率的理论与实验研究

This project is planned to optimize the range separation parameter w through the self-consistent restriction system, aiming at the physical motivated correction for the long-range Coulomb interaction. A computational method can be established to enable accurate and quantitative description of the intramolecular and intermolecular charge-transfer (CT) state. In the meantime, a theoretical model is expected to develope suitable to predict the exciton dissociation rate and change recombination rate in the multi-component complex system.To provide an insight into the cooperative relationship between intramolecular and intermolecular CT processes, we build an organic solar cell material model with more practical significance: intramolecular and intermolecular CT process coexisting system (D1-A1/A2),where the intramolecular CT system (D1-A1) is considered as the donor of organic solar cell matrial system. In order to obtain the enhanced absorption and emission from the intramolecular CT state,many factors are taken into account, such as the electron-donating and electron-withdrawing strength of D1 or A1,the electronic coupling strength,linking modes, composition ratio between D1 and A1, and stacking modes, and so on.It ensures the high yield of the intramolecular CT exciton.The relationship between intramolecular and intermolecular CT process is investigated to understand the mechanism of the exciton dissociation and change recombination processes in the complex system of D1-A1/A2. It will reveal the noval designing ideas of molecular structure to further improve the photoelectric conversion efficiency of the organic solar cell materials.

本项目拟通过体系自洽优化区间分离参数w，实现对库仑作用长程渐近线行为校正，探索可准确定量描述分子内和分子间电荷转移（CT）态的计算方法，发展适合预测多组分复杂体系的激子分离复合速率理论模型。为阐明分子内和分子间CT过程的协同关系，构筑更具实际意义的有机太阳能电池模型体系：分子内和分子间CT过程共存体系（D1-A1/A2），其中分子内CT 体系（D1-A1）作为有机太阳能电池体系的Donor.调控D1/A1的给受电子能力、耦合强度、连接方式、组成比例、堆积方式等因素增强分子内CT吸收和发射，保证高效率分子内CT激子产生。考察分子内和分子间CT过程的相互关系，探讨复合体系D1-A1/A2中激子分离和电荷复合过程的机理，进一步揭示提高有机太阳能电池材料光电转换效率的分子结构设计新理念。

项目从有机光电材料的结构-性质关系研究入手，重点研究电荷转移激发态的准确定量理论预测；杂化局域-电荷转移激发态的形成条件、电子结构组成、及其精确调控；杂化局域-电荷转移激发态组成特征与光电性能的关系；高效率杂化局域-电荷转移激发态发光材料分子结构设计与器件性能等。提出并发展了如下原创性的材料设计理念：（1）发展了杂化局域-电荷转移（HLCT）激发态材料的设计新概念，实现光致发光效率和激子利用率的同时提升；（2）发现了有机电致发光器件中非常规的高能激发态（热激子）反向系间窜越新途径，实现接近100%的激子利用且显著抑制器件效率滚降。近四年在Angew Chem Inter Ed, Adv. Funct. Mater., Chem. Sci.,等杂志发表SCI标注论文18篇，上述工作近四年被引用500余次，3篇论文入选ESI高被引论文，3篇论文为杂志封面论文。