Collaborative Research: Directing Charge and Energy Flow in Discrete Nanocrystal-Dendrimer Hybrids and in Their Assemblies

在这个由化学系的大分子，超分子和纳米化学项目资助的合作项目中，德雷克塞尔大学的Jason巴克斯特教授和宾夕法尼亚大学的Christopher Murray教授正在开发由两种成分组成的新粒子。核心是由半导体制成的纳米颗粒，附着在核心上的是被称为树枝状聚合物的分支有机分子。这些纳米晶-树枝状聚合物（NCD）混合物颗粒提供了有前途的和上级的光学和电子性质，其可以通过组成有机和半导体组分的化学设计来定制，以在纳米长度尺度上操纵电荷和能量的流动。 NCD平台在许多领域和应用中具有广泛的影响潜力，包括太阳能电池，固态照明和显示技术，生物成像，光催化燃料生产和化学合成。在这个项目中，无机NC供体被功能化与定制的树枝状配体，结合分子受体，精确地控制受体的位置和取向，以实现电荷和能量转移的基本研究。对这些NCD混合物的研究极大地推进了对有机/无机界面处的光物理过程的理解，并且正在建立新的设计规则以优化NCs的量子态与官能化树枝化基元的分子能级之间的耦合。NCD杂化物利用有机和无机合成的进展，提供了一类新的可溶液加工的构建模块，以设计能量的流动以及电荷的分离和传输。 该项目的目标包括合成和表征NCD混合纳米结构库，以及测量NCD中超快电荷和能量转移的动力学和理解机制。 这项工作的更广泛的技术影响包括设计和发现下一代粒子的潜在社会效益，这些粒子在光电和光催化器件中提供上级性能。 更广泛的非技术影响包括研究生和本科生的教育和培训，以及对西费城承诺区内代表性不足的群体的宣传。

In this collaborative project funded by the Macromolecular, Supramolecular and Nanochemistry program of the Chemistry Division, Professor Jason Baxter of Drexel University and Professor Christopher Murray of the University of Pennsylvania are developing new particles comprised of two components. The core is a nanoparticle made from a semiconductor, and attached to the core are branched organic molecules called dendrimers. These nanocrystal-dendrimer (NCD) hybrid particles offer promising and superior optical and electronic properties that can be tailored through chemical design of the constituent organic and semiconductor components to manipulate the flow of charge and energy on nanometer length scales. The NCD platform has potential for broad impact across many fields and applications, including solar cells, solid state lighting and display technology, biological imaging, and photocatalytic fuel production and chemical synthesis.In this project, inorganic NC donors are functionalized with tailored dendrimer ligands that incorporate molecular acceptors, precisely controlling the acceptor location and orientation to enable fundamental investigations of charge and energy transfer. Studies of these NCD hybrids are greatly advancing understanding of photophysical processes at organic / inorganic interfaces and are establishing new design rules to optimize the coupling between the quantum states of the NCs and the molecular energy levels of the functionalized dendrons. The NCD hybrids harness advances in both organic and inorganic synthesis to offer a new class of solution-processable building blocks to engineer the flow of energy and the separation and transport of charge. Objectives of this project include synthesizing and characterizing a library of NCD hybrid nanostructures as well as measuring dynamics and understanding mechanisms of ultrafast charge and energy transfer in NCDs. The broader technical impacts of this work include potential societal benefits from the design and discovery of next-generation particles that offer superior performance in optoelectronic and photocatalytic devices. Broader non-technical impacts include education and training of graduate and undergraduate students, as well as outreach to underrepresented groups within the West Philadelphia Promise Zone.