Polariton and CISS Effects on Photoinduced Electron Transfer from Quantum Confined Semiconductor Nanocrystals

在化学系大分子、超分子和纳米化学项目的支持下，连天全教授和埃默里大学的研究生和本科生团队正在开发两种新的方法来控制量子受限半导体纳米晶体（NCs）的光诱导电子转移（ET），这是光催化和量子信息科学中最重要的过程之一。量子受限半导体纳米材料是一种在能量转换和量子信息科学中具有潜在应用前景的新型材料。在本项目中，第一个目标是利用NC与光学腔模式耦合形成的极化子作为控制光诱导ET的新方法。第二个目标是利用手性诱导自旋选择性（CISS）效应，研究NC给体-手性桥体-受体（D-B-A）配合物对光产生的自旋进行选择性转移。本研究的目标是：1)促进对极化子态形成和衰变动力学的理解；2)直接测量腔内nc -分子受体复合物极化激子介导的ET，并验证理论模型；3)开发具有慢电子自旋弛豫和快速ET速率的nc的设计原则；4)进一步了解CISS在nc -手性桥接受体配合物光诱导ET中的作用。分子极化子是由分子的电子跃迁或振动跃迁耦合到光子腔模式而形成的，自从有报道称它们可以提供一种控制化学反应的新方法以来，在化学领域受到了极大的兴趣。提出的努力集中在极化激元介导的电子转移，因为它在极化激元激活的化学反应中的潜在作用。提出的研究将提供急需的实验数据，以测试当前模型的极化态动力学和极化子介导的ET，以及如何使用空腔来控制ET率的重要见解，为许多潜在的应用。控制电子自旋态对于自旋电子学和量子信息是必不可少的。虽然电子自旋在通过手性材料的传输过程中可以选择性地转移，但这一过程在定量水平上还没有被理解。提出的NC给体-手性桥体-受体平台代表了将光子学与自旋电子学相结合的新方法，在量子信息处理中具有潜在的应用前景。该研究将有助于发展具有慢电子自旋弛豫和快速ET速率的nc的设计原则，并促进对nc -手性桥接受体配合物中光诱导ET的CISS效应的理解。拟议的研究计划还为培养研究生和本科生以及将研究与教学和外展活动相结合提供了独特的机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Professor Tianquan Lian and a team of Emory graduate and undergraduate students are developing two novel ways to control photoinduced electron transfer (ET) from quantum confined semiconductor nanocrystals (NCs), one of the most important processes in photocatalysis and quantum information science. Quantum confined semiconductor NCs are promising novel materials with potential applications in energy conversion and quantum information science. In this project, the first aim is focused on using polaritons formed by coupling NCs with optical cavity modes as a new way to control photoinduced ET. The second aim is focused on NC Donor-chiral Bridge-Acceptor (D-B-A) complexes for selective transfer of light generated spins using chiral-induced spin selectivity (CISS) effects. The goals of the research are: 1) to advance the understanding of the formation and decay dynamics of polariton states; 2) to directly measure polariton mediated ET in NC-molecular acceptor complexes in cavity and test theoretical models; 3) to develop design principles for NCs with both slow electron spin relaxation and fast ET rates; and 4) to advance the understanding CISS effect in photoinduced ET in NC-chiral bridge-acceptor complexes.Molecular polaritons, formed by coupling the molecular electronic or vibrational transition to a photonic cavity mode have received intense interest in chemistry since the reports that they can provide a novel approach for controlling chemical reactions. The proposed effort is focused on polariton mediated electron transfer because of its potential roles in polariton enabled chemical reactions. The proposed study will provide much needed experimental data to test current models of polariton state dynamics and polariton mediated ET, as well as important insights on how to use cavities to control ET rates for many potential applications. Controlling electron spin states is essential for spintronics and quantum information. Although electron spins can be selectively transferred during transport through chiral materials, this process is not understood at the quantitative level. The proposed NC donor-chiral bridge-acceptor platform represents a new approach to combine photonics with spintronics for potential applications in quantum information processing. The proposed study will lead to the development of design principles for NCs with both slow electron spin relaxation and fast ET rates and advance the understanding of the CISS effect in photoinduced ET in NC-chiral bridge-acceptor complexes. The proposed research program also offers unique opportunities for training graduate and undergraduate students and for integrating research with teaching and outreach activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.