基于三重态激子和稀土离子间能量传递的量子剪裁

项目名称： 基于三重态激子和稀土离子间能量传递的量子剪裁

项目编号： No.11504323

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 刘小峰

作者单位： 浙江大学

项目金额： 20万元

中文摘要： 量子剪裁常源于稀土离子4f能级的级联跃迁或不同稀土离子间的能量传递。与这一光子倍增过程类似，一些有机分子的单重态激子会以极快的速率裂变成两个三重态激子。然而由于自旋禁戒，这些三重态激子常无法直接回到基态而发射光子。本项目中，我们将通过能量传递，使处于暗态的三重态激子最终带来荧光发射，从而实现一种新的量子剪裁方式。在所研究的体系中，具有合适4f能级的稀土离子和这些三重态激子形成施主-受主对，三重态激子将通过传能使稀土离子受到激发而发射荧光。本项目将从稀土离子―三重态激子体系的选取和设计入手，通过材料化学手段来制备两者的复合体系，然后通过稳态，瞬态和超快光谱等技术来研究三重态激子和稀土离子间能量传递。在此基础上，我们将此有机―无机复合的量子剪裁体系和半导体光电池结合，研究量子剪裁对可见及紫外光区能量转换效率的影响。本项目的成果将推动这一有机―无机复合体系在光电子领域的研究和应用。

中文关键词： 稀土发光材料；下转换发光材料；能量传递；三重态激子

英文摘要： Quantum cutting is often resulted from the cascade emissions from 4f levels of rare earth (RE) ions, or from the energy transfer between different RE ions. Similar to this photon multiplication process, for certain organic molecules photon-generated singlet exciton undergoes rapid “singlet fission”, ending up with two triplet excitons. These triplet excitons, however, do not result in fluorescence as it is spin-forbidden for the transition to the ground spin-singlet state. In this project, the non-emissive triplet excitons are converted to photon emission by means of energy transfer, thereby enabling a new type of quantum cutting. In the examined system, RE ions with suitable 4f levels and triplet excitons server respectively as the acceptor and donor; and the emission from RE ions are produced as a consequence of sensitization by the triplet excitons. This project will begin with the design and the selection of RE ion-triplet exciton pair. The hybrid systems will be accessed by different material chemistry process, and the energy transfer process from triplet excitons to RE ions will be examined by steady state, transient state and ultrafast spectroscopy. Furthermore, the developed organic-inorganic hybrid quantum cutting systems will be incorporated into photovoltaic devices, and the influence of quantum cutting on the performance of the system at visible and ultraviolet region will be evaluated. The results of the present project will have important implications for the research and application of organic―inorganic hybrid in the field of optoelectronics.

英文关键词： rare-earth-based luminescent materials;downconversion;energy transfer ;triplet exciton