Collaborative Research: Dye Molecule-Anchored Platinum Nanocatalysts

合作研究：染料分子锚定铂纳米催化剂研究最深入的低成本太阳能转换系统之一是染料敏化太阳能电池（DSSC），其中附着在纳米半导体上的染料分子吸收阳光并向半导体注入电子。电子可以被提取出来用于发电，但在染料重复这个循环之前，它的电子必须被溶解的氧化还原对反应所取代。这种氧化还原对的一种选择是结合碘离子和三碘离子，这两种离子都非常便宜和丰富。碘离子/三碘离子对几乎是理想的，但有一个问题：当电子从这些离子转移到染料时，会损失大量的能量。该项目旨在通过在染料与碘化物/三碘化物反应的位置精确定位纳米级催化剂来减少能量损失。该奖项是为了表彰康涅狄格大学的Alexander G. Agrios教授和罗格斯大学（Rutgers University）的Elena Galoppini教授在纳米颗粒合成和DSSC器件制造和测量方面的合作。纽瓦克，以表彰其合成专业知识，该奖项来自于之前的EAGER奖。这项工作有可能将DSSC的太阳能转换效率提高50%，同时保留廉价的氧化还原对。此外，利用分子设计将催化金属纳米颗粒直接拴在电化学反应现场的概念可以应用于其他类型的可再生能源项目，如光催化系统。这项研究将与太阳能电池作为K？12教育解释化学，工程和能源的概念，并激发和激励下一代的STEM学生和研究人员。这些活动将针对代表性不足的群体，包括来自纽瓦克市区的高中生，也通过ACS项目SEED计划进行。这个项目使用了特制的染料分子，在分子的两侧有两个不同的附着基团。其中一个基团（羧酸）附着在二氧化钛（TiO2）等金属氧化物的表面。另一个基团（硫烷）附着在某些金属上，并将在这里用于锚定铂纳米粒子（Pt NPs）。这个项目有三个主要的智力组成部分。首先，制造tio2 -染料-催化剂组件将需要(a)制备所需的Pt NPs， (b)合成专门的染料分子，以及(c)组装组件以获得所需的结构。第二，团体的能力？分子整流?将在其与Pt NP的连接点处并入染料中，以确保电子按预期从Pt NP转移到染料中，而不是反向转移，否则会使设备短路并降低其太阳能转换效率。第三，染料分子中的电子能级将通过结构修饰来调整，使电子在期望的方向上以最小的能量损失快速转移。

Collaborative Research: Dye Molecule-Anchored Platinum NanocatalystsOne of the most intensely studied systems for low-cost solar energy conversion is the dye-sensitized solar cell (DSSC), in which a dye molecule attached to a nanoparticulate semiconductor absorbs sunlight and injects an electron into the semiconductor. The electron can be extracted and used for electrical power, but before the dye can repeat the cycle, its electron must be replaced by reaction with a dissolved redox couple. One option for this redox couple combines iodide and triiodide ions, both of which are extremely cheap and abundant. The iodide/triiodide couple is nearly ideal for this purpose but for one problem: electrons lose a significant amount of energy while transferring from these ions to the dye. This project aims to reduce that energy loss by positioning a nano-sized catalyst precisely at the site where the dye reacts with the iodide/triiodide. The award is for a collaboration between Prof. Alexander G. Agrios at the University of Connecticut, providing expertise in nanoparticle synthesis and DSSC device fabrication and measurement, and Prof. Elena Galoppini at Rutgers University?Newark, for the synthesis expertise, and is derived from a previous EAGER award to the investigators. The work has the potential to increase the solar power conversion efficiency of the DSSC by as much as 50% while retaining the cheap redox couple. In addition, the concept of tethering catalytic metal nanoparticles directly to the site of an electrochemical reaction using molecular design can be applied to other kinds of renewable energy projects, such as photocatalytic systems. The research will be coupled to outreach efforts in which solar cells will be used as a teaching tool in K?12 education to explain concepts of chemistry, engineering and energy and to excite and inspire the next generation of STEM students and researchers. These activities will target underrepresented groups including high-school students from the Newark urban area, also through the ACS project SEED program. This project makes use of specially made dye molecules with two different attachment groups on opposite sides of the molecule. One group (a carboxylic acid) attaches to the surface of metal oxides such as titanium dioxide (TiO2). The other group (a thiolane) attaches to certain metals, and will be used here to anchor platinum nanoparticles (Pt NPs). The project has three main intellectual components. First, fabricating the TiO2-dye-catalyst assembly will require (a) preparing the desired Pt NPs, (b) synthesizing the specialized dye molecule, and (c) assembling the components to give the desired structure. Second, groups capable of ?molecular rectification? will be incorporated into the dye at its point of connection to the Pt NP to ensure that electrons transfer from the Pt NP to the dye, as desired, and not in the reverse direction, which would short-circuit the device and reduce its solar power conversion efficiency. Third, electron energy levels in the dye molecule will be tuned by structural modification to the values that will give rapid electron transfer in the desired direction with minimal energy loss.