Plasmon-exciton nanostructures based on 2D semiconductor nanocrystals for near-infrared photonics

在这个项目中，我们将开发新的混合等离子激子纳米结构在近红外（NIR）区域的活性。作为用于制造这些复合结构的材料平台，我们选择铜硫属化物（Cu 2 + xA，其中x = 0-1且A = S、Se或Te）二维（2D）纳米晶体。我们的选择依赖于Cu 2 AlxA的多晶型，其表现出一系列不同的化学计量，以适应各种晶相，以及这些纳米晶体通过阳离子交换进行化学转化的可行性。该项目将联合收割机以下两个主要部分：第一章开发了具有良好控制的尺寸和晶体结构的半导体Cu 2 + xA 2D纳米材料的直接胶体合成及其通过阳离子交换的化学转化反应成半导体2D金属硫族化物，例如CdA、PbA、HgA和Ag 2A，包括它们的异质结构; 2）以平面分层组件的形式制造复合荧光等离子体材料，并使用先进的光谱技术研究层之间的相互作用。该项目中目标2D材料的成分和结构操纵程度将远远超出现有的直接湿化学合成以及化学气相沉积或剥离的最先进方法。控制它们的结构和组成是精确设计其光电性能的关键。从实用的角度来看，具有高吸收系数和高光致发光量子产率的半导体纳米晶体与具有强等离子体共振的纳米颗粒的组合对于提高光电器件的效率是有希望的。这种概念对于近红外区域非常重要，在该区域难以实现高效率。一方面，缺乏用于合成NIR活性铜、铅、汞和银硫族化物2D纳米材料的合成方案，另一方面，实际上尚未研究NIR区域中等离子体和激子结构之间的相互作用，这促使我们追求这些目标。该项目的工作计划分配给一名博士研究员，由两名学生助理提供支持。这项工作预计不仅对胶体2D半导体纳米材料的化学基础及其合成方法产生影响，而且还将提供一系列具有明确应用潜力的各种材料。所得到的材料和结构具有可调的光物理性能，将是非常有前途的候选人在太阳能电池，发光太阳能聚光器，发光二极管和光电探测器的应用。

In this project we will develop novel hybrid plasmonic‒excitonic nanostructures active in the near-infrared (NIR) region. As a material platform for the fabrication of these composite structures we choose copper chalcogenide (Cu2‒xA, where x = 0–1 and A = S, Se or Te) two dimensional (2D) nanocrystals. Our selection relies on polymorphism of Cu2‒xA which exhibits a range of different stoichiometries adapting various crystal phases and a feasibility of chemical transformations of these nanocrystals via cation exchange.The project will combine the following two main parts: 1) development of a direct colloidal synthesis of semiconductor Cu2‒xA 2D nanomaterials with well controlled dimensions and crystal structure and their chemical transformations via cation exchange reactions into semiconductor 2D metal chalcogenides, such as CdA, PbA, HgA, and Ag2A, including their hetero-structures; 2) fabrication of composite fluorescent‒plasmonic materials in the form of planar layered assemblies and investigation of interactions between the layers using advanced optical spectroscopy techniques. Degrees of compositional and structural manipulation of the 2D materials targeted in this project will go far beyond the existing state-of-the-art methods for their direct wet chemical synthesis as well as chemical vapor deposition or exfoliation. Control of their structure and composition is a key to the precise engineering of their optoelectronic properties. From practical point of view, the combination of semiconductor nanocrystals with high absorption coefficients and high photoluminescence quantum yields and nanoparticles with a strong plasmon resonance is promising for the improvement of the efficiency of optoelectronic devices. Such a concept is of great importance for the NIR region, where a high efficiency is difficult to achieve. The lack of synthetic protocols for the synthesis of NIR-active copper, lead, mercury, and silver chalcogenide 2D nanomaterials on one hand, and practically not investigated yet interactions between plasmonic and excitonic structures in the NIR region on the other, motivate us to pursue these goals. The work plan of the project is assigned to a doctoral researcher supported by two student assistants.This work is expected to have impact not only on the fundamentals of chemistry of colloidal 2D semiconductor nanomaterials and their synthetic methodology, but also to provide a range of various materials with a well-defined application potential. The resulting materials and structures with tunable photophysical properties will be very promising candidates for applications in solar cells, luminescent solar concentrators, LEDs, and photodetectors.