Spin-Exchange and Energy Transfer at Hybrid Molecular/Lanthanide Nanoparticle Interfaces to Control Triplet Excitons

SPICE将为自旋1三重态激子的控制提供一个新的范例。SPICE的出发点是我们最近发现，在有机半导体和镧系元素掺杂的无机纳米颗粒的混合系统中，可以将分子自旋自旋交换耦合到Ln 3+离子上的未配对自旋，并将能量从三重态激子转移到Ln 3+，反之亦然（Han等人，Nature 2020）。这为探索和发现打开了一个迷人的领域，SPICE将把联合收割机稳态和超快光谱学与分子和镧系元素纳米颗粒设计结合起来，探索这些新现象，并建立一个全面的机制，理解有机分子中的自旋交换耦合和能量转移。镧系元素纳米颗粒界面，并对新材料和器件功能进行概念验证。主要目标是：1）建立结构-功能关系，以了解以下机制：（a）自旋交换介导的通常禁止的S 0-Tn跃迁的增亮;（B）自旋交换介导的系统间交叉（S1-T1）速率的增强;（c）从三重态激子到Ln 3+的能量转移，反之亦然;（d）三重态-Ln聚变过程（T1+Ln-S1）以给出上转换发射和必须介导该过程的混合Ln-有机电子态。然后，我们将利用产生的见解开发具有优化的能量传递和发射特性的新材料。3）最后，我们将证明LED和具有近红外发射的光泵浦激光器的演示（1300-1600nm）和近红外到蓝色的上转换在非常低的激发功率，可以触发生物环境中的化学反应。SPICE的成功将开辟新的利用三重态激子的途径，可以在从电子学和光电子学到3D打印和光遗传学等领域找到变革性的应用。

SPICE will deliver a new paradigm for the control of spin-1 triplet excitons. The starting point for SPICE is our recent discovery that in hybrid systems of organic semiconductors and lanthanide-doped inorganic nanoparticles it is possible to spin-exchange couple the molecular spin to the unpaired spins on the Ln3+ ions and to transfer energy from triplet excitons to Ln3+ and vice versa (Han et al., Nature 2020). This opens a fascinating area for exploration and discovery, as well as routes to control triplet dynamics in ways not possible via current methods.SPICE will combine steady-state and ultrafast optical spectroscopy with molecular and lanthanide nanoparticle design to explore these new phenomena and build a comprehensive mechanistic understanding of spin- exchange coupling and energy transfer at the organic-lanthanide nanoparticle interface and make proof of concept demonstrations of novel materials and device functionalities. Key aims will be:1) Building structure-function relationships to understand the mechanisms of:(a) spin-exchange mediated brightening of the normally forbidden S0-Tn transitions; (b) spin-exchange mediated enhancement of intersystem crossing (S1-T1) rates; (c) energy transfer from triplet excitons to Ln3+ and vice versa; (d) the triplet-Ln fusion process (T1+Ln-S1) to give upconverted emission and the hybrid Ln-Organic electronic states that must mediate this process.2) We will then use the insights generated to develop new materials with optimised energy transfer and emission properties.3) Finally, we will make proof of demonstrations of LEDs and optically pumped lasers with NIR emission (1300-1600nm) and NIR to blue upconversion at very low excitation powers that can trigger chemical reactions in biological environments.The success of SPICE would open new avenues to harness triplet excitons that could find transformative applications in areas ranging from photocatalysis and optoelectronics to 3D printing and optogenetics.