Functional Materials Based on Well-Defined Colloidal Nanoscale Blocks for Applications in Sensing, Photoelectrochemistry, and Environmental Remediation

拟议的研究旨在进一步推进可定制（尺寸，形状，表面和物理特性）纳米级构建块（NBBs）的合成和表征，特别是实现这些NBBs的功能应用。目标应用包括基于等离子体共振和表面增强拉曼散射（Sers）的传感、光电化学、光催化和环境修复。在过去的6年中，PI的实验室在尺寸和形状控制的纳米级构建块（NBBs）的合成控制方面建立了一个行之有效的记录，重点是功能特性的优化，例如可调表面等离子体共振（SPR）。所开发的NBBs的新奇性和可利用的功能性源自通过自下而上的胶体合成所赋予的尺寸、形状和表面化学的精确控制。具体而言，对于SPR传感，PI的小组合成了银五边形棒和血小板，通过在NBB胶体生长中的尺寸控制，SPR共振的精确位置在几个nm内;而优化的尺寸选择的银十面体导致非常尖锐的SPR峰宽，对SPR传感的灵敏度至关重要。对于表面增强拉曼光谱（Sers）应用，银纳米颗粒的尺寸控制，特别是所开发的规则刻面形态的纳米级空腔（5-50 nm）的精确合成定制，对于证明单个银纳米颗粒的显著Sers增强是至关重要的。因此，拟议研究的下一阶段是扩大NBBs的范围，扩大其有用的功能特性的范围，并专注于实现其应用（SPR，Sers）。提出的研究的三个主要方向是i）进一步开发具有针对特定应用的稳定性和SPR特性的等离子体NBBs; ii）合成用于光电化学应用的新型富电子氧化物NBBs;以及iii）基于开发的NBBs生产原型传感设备。i）对于银NBB的稳定性，研究团队将首先开发它们的金涂层以利用金稳定性，同时保留银的有利等离子体特性。其次，该团队将致力于用二氧化硅和聚合物封装NBBs，以提高稳定性和可定制的等离子体特性。ii）对于导电氧化物NBBs，该团队首先从钌和铱的二氧化物开始，随后将重点转向具有成本优势的3d金属，如锰和铁的氧化物。该团队的目标是在金属-超原子跃迁附近实现可调的有利性质（约为1000。20-200个原子簇）。iii）为了实现NBBs应用，研究将集中在与其他研究小组和工业合作伙伴合作开发基于SPR和Sers的传感器原型。用于SPR感测的主要NBB包括镀金NBB和壳NBB。PI的团队目前处于最佳位置，可以通过获得的NBBs合成库来实现这些目标。拟议研究的主要好处是利用NBBs合成方面已开发的专业知识和能力，并进一步应用这些知识来创造新材料，其中精确的尺寸和表面控制对于实现先进的功能特性和应用至关重要。基于开发的NBB基材料的应用范围包括等离子体和Sers传感，光电化学，水分解阳极和基于氧化催化的环境修复。SPR传感将是主要的直接焦点。

The proposed research is aimed at further advancement of the synthesis and characterization of tailorable (by size, shape, surface, and physical properties) nanoscale building blocks (NBBs) and specifically at the realization of functional applications of these NBBs. Targeted applications include sensing based on plasmonic resonance and surface-enhanced Raman scattering (SERS), photoelectrochemistry, photocatalysis, and environmental remediation. During the last 6 years, the PI’s laboratory established a proven track-record in synthetic control over size- and shape-controlled nanoscale building blocks (NBBs) with the emphasis on optimization of functional properties, such as tuneable surface plasmon resonance (SPR). The novelty and utilizable functionality of the developed NBBs originate from the achieved precise control in size, shape, and surface chemistry imparted by the bottom-up colloidal synthesis. Specifically, for SPR sensing, the PI’s group synthesized silver pentagonal rods and platelets with the precise position of SPR resonance within a few nm through the size control in the NBB colloidal growth; while optimized size-selection of silver decahedra resulted in the remarkably sharp SPR peak width, crucial for the sensitivity of SPR sensing. For surface-enhanced Raman spectroscopy (SERS) applications, the size control of the silver nanoparticles, and especially the precise synthetic tailoring of the nanoscale cavities (5-50 nm) of the developed regular faceted morphologies, were crucial to demonstrate remarkable SERS enhancement by single silver nanoparticles. Consequently, the next phase of the proposed research is to expand the range of NBBs expanding on the range of their useful functional properties and to focus on realization of their applications (SPR, SERS) . Three major directions of the proposed research are i) further development of plasmonic NBBs with stability and SPR properties tailored for specific applications; ii) synthesis of novel electron-rich oxide NBBs for photoelectrochemical applications; and iii) production of prototype sensing devices based on the developed NBBs. i) For the stability of silver NBBs, the research team will first develop their coating with gold to take advantage of gold stability, while retaining advantageous plasmonic properties of silver. Secondly, the team will work on encapsulation of NBBs with silica and polymers for improved stability and tailorable plasmonic properties. ii) For the conductive oxide NBBs, the team first started with ruthenium and iridium dioxides and subsequently changed the emphasis to cost-advantageous 3d metals, such as manganese and iron oxides. The team aims at realizing tunable advantageous properties in the vicinity of the metal-superatom transition (at ca. 20-200 atoms clusters). iii) For the implementation of NBBs applications, the research will focus on prototype development of sensors based on SPR and SERS in collaboration with other research groups and industrial partners. Primary NBBs for SPR sensing include gold-plated and shell NBBs. The PI’s group is currently in the best position to accomplish these goals with the attained synthetic library of NBBs. Tangible benefits of the proposed research are in capitalizing on the developed expertise and capabilities in the synthesis of NBBs and further applying this knowledge to create novel materials where precise size- and surface-control is absolutely critical for the realization of advanced functional properties and applications. The range of applications based on the developed NBB-based materials includes plasmonic and SERS sensing, photoelectrochemistry, anodes for water splitting, and environmental remediation based on oxidative catalysis. SPR sensing will be the primary immediate focus.