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Theoretical investigation of toxic-metal-free nanocrystals for technological applications

无毒金属纳米晶体技术应用的理论研究

基本信息

批准号：
2037499
负责人：
金额：
--
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2037499
关键词：
Theoretical investigation toxic metal free

项目摘要

Context of research: Nanotechnology centers around the ability to engineer materials at the nanoscale (that is, to manipulate structures with typical dimensions of the order of 1/100,000 of the thickness of a human hair), for technological applications. Colloidal quantum dots (QDs, aka nanocrystals, NCs) are chemically synthesised single-crystalline spherical semiconductor nanostructures with typical dimensions of a few nanometers which exhibit several characteristics that make them attractive for this field: (i) their size-tunable optical properties enable their application in very different fields such as optoelectronics (in lasers and LEDs), as well as biology and medicine (as organic molecule markers), and PV, allowing their absorption energies to be tailored to maximise solar photon absorption; (ii) their colloidal (i.e., chemical) nature enables low cost and large scale production; (iii) the very high degree of size monodispersity (less than 5%) achievable in their synthesis provides reproducibility and growth control. These properties make them also compatible with existing fibre-optic technologies and useful as building blocks for bottom-up assembly of various optical and electronic devices, including optical amplifiers, lasers and single-electron transistors. However, most of the nanocrystals exploited in such applications are made of Cd- and Pb-based materials (i.e., of CdX and PbX, where X=S, Se, Te), which are highly toxic for humans and the environment. It is therefore paramount to find non-toxic alternatives that can represent viable substitutes to such well characterised and well performing materials. This is the aim of this project.Aims and objectives:To apply the atomistic semiempirical pseudopotential method (SEPM) developed in the Solid State Theory group at the National Renewable Energy Lab, Golden (CO) U.S.A., to theoretically screen different ("novel" and more conventional) Cd- and Pb-free colloidal materials and alternative topological structures for technological applications at the nanoscale, ranging from PV to nanoelectronics. Possible materials include Ga- and In- based ones (i.e., GaX and InX, where X=As, Sb and P), whereas possible structures include rods and tetrapods (potentially better suited for transport in films), as well as spherical nanocrystals. Potential applications and benefits:One of the many possible implications of the study on tetrapods of different materiasl could be the enhancement of miniband formation and transport in QD films, with applications ranging from PV to nanoelectronics (transistors). Others could involve the design of novel biosensors exploiting the long carrier lifetimes in Ga-based materials.Furthermore, the student will develop a deep knowledge and competence in the use of a state-of-the-art theoretical modelling method and, through collaborations with national and international experimental groups and attendance to conferences, will start building a network of collaborators.

研究背景：纳米技术的核心是在纳米尺度上设计材料的能力（即，操纵人类头发厚度的1/100，000的典型尺寸的结构），用于技术应用。胶体量子点量子点（QD，又名纳米晶体，NC）是化学合成的单晶球形半导体纳米结构，具有几个纳米的典型尺寸，表现出几个特性，使它们对这个领域有吸引力：（i）它们的尺寸可调的光学性质使它们能够应用于非常不同的领域，（在激光器和LED中），以及生物学和医学（作为有机分子标记），和PV，允许它们的吸收能量被定制以最大化太阳光子吸收;（ii）它们的胶体（即，化学）性质使得能够低成本和大规模生产;（iii）在它们的合成中可实现的非常高程度的尺寸单分散性（小于5%）提供了再现性和生长控制。这些特性使它们也与现有的光纤技术兼容，并可用作各种光学和电子设备（包括光学放大器，激光器和单电子晶体管）自下而上组装的构建模块。然而，在这种应用中开发的大多数纳米晶体由Cd基和Pb基材料制成（即，CdX和PbX，其中X=S、Se、Te），其对人类和环境具有高毒性。因此，找到无毒的替代品是至关重要的，这些替代品可以代表这些特性良好且性能良好的材料的可行替代品。目的和目标：应用美国国家可再生能源实验室固态理论组开发的原子半经验赝势方法（SEPM），从理论上筛选不同的（“新的”和更传统的）镉和铅的胶体材料和替代拓扑结构的技术应用在纳米级，从光伏到纳米电子。可能的材料包括Ga基和In基材料（即，GaX和InX，其中X=As、Sb和P），而可能的结构包括棒和四脚体（可能更适合于在膜中传输）以及球形纳米晶体。潜在的应用和好处：对不同材料的四足体的研究的许多可能的影响之一可能是增强量子点薄膜中的迷你带形成和传输，应用范围从光伏到纳米电子（晶体管）。此外，学生还将在使用最先进的理论建模方法方面积累深厚的知识和能力，并通过与国家和国际实验小组的合作以及参加会议，开始建立合作者网络。