Efficient thermally-activated delayed fluorescence in endohedral metallofullerenes

最近在面内金属富勒烯(EMF)Y3N@C80中发现了有效的热激活延迟荧光(TADF)，这表明EMF可以成为强发光材料。然而，对其激发态的光物理性质和电子分布的了解还不是很清楚。在本项目中，将对一系列电动势及其衍生物的发光性质进行系统的研究。变温稳态和时间分辨发光测量将揭示其他显示有效TADF的电动势。对于不同加成方式的富勒烯环基和自由基加合物，将研究化学衍生化对TADF的影响。常规的和光学探测的电子自旋共振谱将被用来研究电动势的光激发三重态中的自旋密度分布。依赖于时间的密度泛函计算将被用来预测电动势中电子激发的能量和空间分布，并使实验观测合理化。这项工作将揭示影响电动势辐射和非辐射衰减的机制和电动势发光效率的因素，并建立它们作为红色到近红外范围内的发射体、作为热敏传感器或作为单线态氧增敏剂的潜力。

The recent discovery of efficient thermally activated delayed fluorescence (TADF) in the endohedral metallofullerene (EMF) Y3N@C80 indicates that EMFs can be strongly luminescent materials. However, the photophysical properties and the electron distribution in their excited states are not well understood. In this project a systematic study of the luminescent properties of a series of EMFs and their derivatives will be performed. Variable-temperature steady-state and time-resolved luminescence measurements will reveal other EMFs showing efficient TADF. The influence of chemical derivatization on the TADF will be studied for fullerene cyclo- and radical adducts with different addition patterns. Conventional and optically-detected electron spin resonance spectroscopy will be used to study the spin density distribution in the photoexcited triplet states of EMFs. Time-dependent DFT calculations will be performed to predict energetics and spatial distribution of electron excitations in EMFs and rationalize experimental observations. This work will disclose the factors affecting the mechanism of the radiative and non-radiative decay of the photoexcited states and efficiency of the luminescence of EMFs and establish their potentials as emitters in the red to NIR range, as thermal sensors, or as singlet oxygen sensitizers.