Charge Effects on Optoelectronic Properties of Nanorod Heterostructures

非技术描述：将半导体晶体的尺寸减小到纳米长度尺度可以获得大晶体中不存在的有用的光学和电学特性。这些微小的半导体纳米晶体在显示、照明和生物医学成像方面有着创新的应用。开发此类应用的重要之处是了解电荷如何影响光学和电学特性，以及控制纳米晶体中的电荷效应的能力。该项目阐明了电荷在具有形状、光学和成分各向异性的新型溶液处理半导体纳米晶体中的影响，这为操纵电荷提供了新的手段。参与该项目的学生将面临多方面的挑战，并有充分的教育和培训机会，成为跨学科科学和工程领域的领导者。PI致力于利用该研究项目产生的研究成果来加强教学，并向公众推广纳米科学的利益。技术描述：最近获得的具有复杂而明确的外延界面的多组分半导体纳米晶体，特别是那些具有棒状（或纳米棒）的纳米晶体，代表了一类新兴的胶体半导体材料。这些纳米棒中设计的主动异质结和结构/光学各向异性为控制载流子的分离、注入、提取和重组提供了新的手段。然而，周围的诱导电荷，无论是有意还是无意，都可能导致完全不同的行为，而不是基于固有或电荷中性材料的假设。该项目系统地研究了接触电荷传输层和电极的工作功能如何影响充电行为，以及这些多异质结纳米棒中预先存在的电荷如何影响载流子注入、光致发光和电致发光。该项目还研究了如何利用结构/光学各向异性和主动异质结来控制充电行为。通过该项目获得的知识有助于确定关键参数和方法，以实现增强的材料性能和设备性能。

Nontechnical Description: Reducing the sizes of semiconductor crystals to nanometer length scales can lead to useful optical and electrical properties that do not exist in large crystals. These tiny semiconductor nanocrystals are finding innovative applications in displays, lighting, and biomedical imaging. Important to developing such applications is the understanding of how electrical charges affect optical and electrical characteristics as well as the ability to control charging effects in nanocrystals. This project elucidates the effects of electrical charges in an emerging class of solution-processed semiconductor nanocrystals with shape, optical and compositional anisotropy, which offers novel means of manipulating electrical charges. The students participating in this project tackle multi-faceted challenges with ample educational and training opportunities necessary for becoming leaders in interdisciplinary science and engineering fields. The PI is committed to utilizing the research results generated in this research project to enhance teaching and promoting benefits of nanoscience to the general public.Technical Description: Recently achieved multi-composition semiconductor nanocrystals with complex yet well-defined epitaxial interfaces, especially those with rod shapes (or nanorods), represent an emerging class of colloidal semiconductor materials. Active heterojunctions and structural/optical anisotropy designed into these nanorods provide novel means of controlling separation, injection, extraction and recombination of charge carriers. However, surrounding induced charges, whether intentional or not, can lead to an entirely different behavior than one often assumed based on an intrinsic or charge neutral material. This project examines systematically how work functions of contacting charge transport layers and electrodes affect charging behavior and how pre-existing charges in these multi-heterojunction nanorods influence carrier injection, photoluminescence and electroluminescence. The project also investigates how structural/optical anisotropy and active heterojunctions can be utilized to control charging behavior. The knowledge gained through this project helps to identify critical parameters and means for achieving enhanced materials properties and device performance.