可(水)溶性酞菁超分子制备与弱光上转换增强/双光子特性研究

Two-photon absorption (TPA) is a nonlinear optical process of a molecule from the ground state to the first excited state by simultaneous absorb two photons. Organic conjugated molecules with strong two-photon absorption (TPA) emerge as very attractive applications such as up-converted lasing, two-photon polymerization in the microfabrication, three-dimensional fluorescence imaging and two-photon photodynamic therapy. However, two-photon absorption with up-conversion has always been associated with the use of very high intensity light excitation (on the order of MW~GM/cm-2) that has the serious application limitation. .In comparison to two-photon absorption described above, the fundamental advantage of the triplet-triplet annihilation-supported bimolecular photon up-conversion process is that it can be carried out at the very low intensity of excitation source (as low as 1 W/cm-2). The process is considered as two processes: the transfer of the sensitizer triplet to the emitter triplet (TTT) and the triplet-triplet annihilation of the emitter (TTA). Although the excitation light is low, the up-conversion efficiency is very low (less than 7%), which still has the serious application limitation. .In this project, we focus on the supermolecular system wherein soluble phthalocyanine as sensitizer bonding with cyclodextrin (CD) as "super-link" to physically attaching the emitters of tetracene, or anthracene and or pentacene derivatives. Especially, the objects in this project are as follows: .1) to synthesize a series of the supermolecular systems of phthalocyanine(Pc)－cyclodextrin (CD)－emitter(A);.2) to investigate how to increase the up-conversion efficiency of such the supermolecular systems at the low intensity of excitation;.3) to research the two-photon characteristics of such the supermolecular systems via two-photon polymerization;.4) to understand the relationships of the supermolecular structure, the triplet-triplet transfer (TTT)/triplet-triplet annihilation (TTA) and up-conversion enhancement. .In sum, our aim is to provide both experimental and theoretical data for two-photon process pumped by the low intensity of light source.

"双光子"概念提出已有80年历史，"双光子科学"作为热点课题有20年时间，至今仍无法突破应用瓶颈，原因在于"双光子过程"受限于"强光泵浦"。本项目首次将"双光子"与"弱光场"联系在一起研究：提出"可(水)溶性酞菁超分子制备与弱光上转换增强/双光子特性研究"课题；展开"超分子－弱光场－双光子过程－上转换效率增强"新机制研究，以期突破遏制双光子科学与技术的应用瓶颈。.拟对酞菁(Pc)进行轴向和周边取代，采用高效点击化学反应接枝Pc与环糊精(CD)，CD空腔作为"超联接"，构筑"Pc－CD/A(发光体)"超分子。促进三线态能量转移(TTT)和三线态湮灭(TTA)、遏制Pc和A之间单线态能量转移、抑制逆向三线态能量转移、提高上转换效率。在研究"超分子结构－三线态转移/三线态湮灭－弱光上转换"构效关系基础上，探索弱光场双光子聚合反应，求证双光子过程量子特性，为该领域提供重要实验数据和理论依据。

“双光子”概念提出已有 80 年历史，“双光子科学”作为热点课题有 20 年时间，至今仍无法突破应用瓶颈，原因在于“双光子过程”受限于“强光泵浦” 。本项目将“双光子”与“弱光场”联系在一起研究：提出“可(水)溶性酞菁超分子制备与弱光上转换增强/双光子特性研究”课题；展开“超分子－弱光场－双光子过程－上转换效率增强”新机制研究，以期突破遏制双光子科学与技术的应用瓶颈。.设计并合成了三大类环状金属配体物（金属卟啉、金属酞菁和三联吡啶金属配合物），通过络合金属离子获得宽波段强吸收特性的光敏剂，利用重原子效应增强旋轨耦合作用，提高三线态系间窜越几率。发现了一种可以明显提高三线态湮灭上转换效率的微环境介质—β-环糊精，并开发了一种新型上转换介质：水包油(O/W)型微乳液体系。研究“超分子结构－三线态转移/三线态湮灭－弱光上转换”构效关系基础上，探索弱光场双光子聚合反应，求证双光子过程量子特性，为该领域提供重要实验数据和理论依据。