The Mechanisms of Size, Shape, and Facets Control in Colloidal SnTe Nanostructures for Advanced Optoelectronics

低维半导体纳米材料如碲化锡（SnTe）可以利用量子约束效应的优势，显示出巨大的热电转换潜力。作为一种IV-VI窄带隙半导体（0.18 eV，体），SnTe表现出本质上较高的载流子浓度，这导致了相对较低的塞贝克系数，但通过掺杂和合金化对材料进行优化，为该材料的热电应用提供了很大的希望。作为第一个被预测的拓扑晶体绝缘体，SnTe的研究从理论和实验两个方面探索了表面态的物理和应用。此外，SnTe还具有超导性和铁磁性等奇异的电子特性，这使得它在高性能热电材料、相变材料、红外发射和检测材料、光伏器件以及铁电材料中具有广泛的应用前景。在本项目中，申请人拟探索控制低维SnTe纳米材料的尺寸和形状的新方法，以改善SnTe纳米材料的光学各向异性、可调谐的电子效应、独特的光电行为，并增强其传感能力。控制纳米材料的粒径、形状和表面仍然是胶体合成SnTe纳米材料的一个挑战。此外，动力学因素的控制和介质中螯合剂的引入决定了纳米体系的形成具有相纯度、尺寸分布和形状狭窄的特点。更重要的是，据申请人所知，没有明确和系统的趋势将SnTe与其光学或光电性质联系起来。本研究项目将重点研究SnTe纳米晶体的形貌与光电性能之间的关系。在合成方面，将详细研究影响SnTe纳米颗粒形貌的物理参数（如反应温度、加热时间等）和化学参数（如配体类型、溶剂性质等）。该项目还将重点研究最终影响纳米颗粒形状的因素（如电子结构、facet形成等）以及不同纳米结构的胶体SnTe的电输运特性，以深入了解不同形貌与其光学或光电特性之间的联系。从基础研究的角度来看，该项目将有助于了解SnTe纳米结构与其光电性能之间的基本联系。本研究结果将有利于可控合成具有明确结构的SnTe，以及探索新型光学或光电器件和拓扑晶体绝缘体。

Low-dimensional semiconductor nanomaterials such as tin telluride (SnTe) can adopt advantages based on the quantum confinement effect, suggesting great potential for heat-electricity conversion. As a IV-VI narrow bandgap semiconductor (0.18 eV, bulk), SnTe exhibits an intrinsically high charge carrier concentration, which results in a relatively low Seebeck coefficient, but optimization of the material through doping and alloying offers great promise for thermoelectric applications of this material. As the first predicted topological crystalline insulators, SnTe has been studied to explore the physics and applications of the surface states both theoretically and experimentally. In addition, SnTe exhibits exotic electronic properties such as superconductivity and ferromagnetism that make it a promising material for the use in high-performance thermoelectric materials, phase-change materials, infrared emission and detection materials, photovoltaic devices as well as ferroelectrics for a wide range of applications. In this project, the applicant intends to explore new approaches to control the size and shape of low-dimensional SnTe nanomaterials to improve the optical anisotropy, tunable electronic effects, unique optoelectronic behavior, and enhance sensing capabilities of SnTe nanomaterials. Controlling the particle size, shape and facets is still a challenge for the colloidal synthesis of SnTe nanomaterials. In addition, control of kinetic factors and the introduction of chelating agents in the medium decide the formation of nano-systems with phase purity, narrow size distribution and shapes. More importantly, to the applicant’s knowledge, no clear and systematic trends linking SnTe to their optical or optoelectronic properties have been established. This research project will focus on the relationship between the morphology and optoelectronic properties of SnTe nanocrystals. In terms of synthesis, the physical (e.g., reaction temperature, heating time, etc.) and chemical (e.g., type of ligand, nature of the solvent, etc.) parameters that affect the morphology of SnTe nanoparticles will be studied in detail. The proposed project also focuses on the factors that ultimately affect the shape of nanoparticles (e.g., electronic structure, facet formation, etc.) and the electric transport properties of the colloidal SnTe with different nanostructures to gain a deep understanding of the connection between the different morphologies and their optic or optoelectronic properties. From the fundamental research point of view, the project will help to understand the basic connection between SnTe nanostructures with their optoelectronic properties. The results of this study will benefit the controllable synthesis of SnTe with defined structures as well as the exploration of novel optic or optoelectronic devices and topological crystalline insulators.