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

在这个由化学部大分子、超分子和纳米化学项目资助的合作项目中，德雷塞尔大学的杰森·巴克斯特教授和宾夕法尼亚大学的克里斯托弗·默里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粒子，附着在核心上的是被称为树状大分子的分支有机分子。这些纳米晶体-树状大分子（NCD）混合粒子具有优越的光学和电子特性，可以通过有机和半导体成分的化学设计来定制，以控制纳米长度尺度上的电荷和能量流动。NCD平台在太阳能电池、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等许多领域和应用中具有广泛影响的潜力。在这个项目中，无机NC供体被定制的树状配体功能化，其中包含分子受体，精确控制受体的位置和方向，从而实现电荷和能量转移的基础研究。这些NCD杂化体的研究极大地促进了对有机/无机界面光物理过程的理解，并建立了新的设计规则来优化NCs的量子态与功能化树突分子能级之间的耦合。NCD混合材料利用有机和无机合成技术的进步，提供了一类新的可溶液处理的构建模块，用于设计能量流和电荷的分离和传输。本项目的目标包括合成和表征非镉杂化纳米结构库，以及测量非镉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了卓越的性能。更广泛的非技术影响包括研究生和本科生的教育和培训，以及向西费城承诺区内代表性不足的群体伸出援手。

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.