多枝共轭体系光诱导电荷转移过程及发光动力学研究

Organic conjugated system attracted a lot of attentions in optical information, optical-electron conversion, optical-chemical energy conversion fields,because of its promising characters. The absorption cross section of multrbranched organic conjugated system gain promising increase (>5-fold) compared with one branched case. However, the property is still not enough for pratical applications, we should design the molecule structure to futher increase the photon absorption cross section and carriers quantum yields. The excited state properties, charge transfer process and the routine of decay, the life time always affect the absorption properties and the carriers quantum yields. The time-resolved spectroscopy can study these ultrafast processes. We selected a series of multibranched organic conjugated system, study the charge transfer process and photoluminescence dynamics, make sure the routine of electron transfer process,the information between photon and matters, thus understand the relation between properties and structure relation deeply, thus modify and increase the properties of new multrbranched organic conjugated system. Then the results we get will be applied on the molecules design of new system, increase the absorption cross section and carriers quantum yields, improving the development of the application process.

有机共轭体系凭借其特异的性质在光信息、光电转换、光化学能转换等领域备受瞩目。与单枝结构相比多枝共轭体系的吸收截面呈现奇异的非线性增强（约5倍以上），然而目前其性能依然无法满足应用要求，必须通过分子剪裁和设计进一步提高吸光截面及载流子利用效率。激发态性质、电荷转移过程、光生载流子弛豫途径和寿命等因素与材料的吸收截面及光生载流子利用效率密切相关。时间分辨光谱可以弥补稳态光谱的不足研究这些重要的超快过程。申请人选取一系列典型多枝共轭系列为研究模型，结合稳态光谱和时间分辨光谱技术深入研究电荷转移过程及发光动力学，明晰分子激发后的电荷转移途径、分子激发态以及光与物质相互作用信息，深入理解结构对性能及动力学的影响，从而为改进和提高多枝共轭体系提供理论依据。同时，将得到的研究结果应用于新型多枝共轭体系的分子设计，不断提高有机共轭体系的吸收截面及光生载流子利用效率，推进有机共轭体系的实用化进程。

有机共轭体系在很多领域有着诱人的应用前景，然而这些应用往往要求分子具有大的非线性吸收截面或者高的荧光量子产额或者二者兼备。本项目选取一系列典型多枝共轭体系为研究模型，结合稳态光谱和时间分辨光谱技术研究分子结构与激发态性质、电荷转移、光生载流子弛豫途径和寿命等因素之间的关系，从而明晰性能增加及激发态释能调控机理。通过本项目研究，我们得到了较为系统的多枝共轭体系功能-激发态性质、电荷转移以及发光动力学信息，加深了分子电荷转移特性对发光动力学以及材料性能影响机理的新认识，为新型体系优化设计提供了可靠的理论依据和支持。同时，我们将第一阶段研究结果应用于第二阶段多枝共轭体系的分子设计，初步得到了几种性能优异的新材料。本项目研究结果有效推动了有机共轭体系在光限幅、多光子荧光成像、光动力学疗法等领域的实用化进程。