Spin Injection and Relaxation in Organic Semiconductors

技术描述：在过去的几年里，有机自旋电子学的研究取得了进展。有机材料的一个重要优势是由于原子序数小而具有固有的较长的自旋寿命，导致较少的自旋-轨道相互作用。最近报道了高达300%的有机磁阻响应。自旋注入和载流子复合在有机发光二极管中的作用也被广泛观察到。尽管潜力很大，但仍然存在具有挑战性的根本性问题，包括控制自旋注入和自旋翻转的机制。众所周知，界面在有机自旋电子学中是至关重要的。为了实现有机自旋电子学的潜力，必须弥合对有机自旋电子学基本过程的认识鸿沟。本项目的目标是研究自旋注入和驰豫动力学，以了解对有机自旋电子学发展至关重要的潜在基本机制。研究了不同无机衬底与有机材料界面的自旋注入效率，并研究了有机半导体薄膜的自旋驰豫动力学。研究的主要工具是自旋分辨光电子能谱，辅之以其他表面分析技术，包括紫外线和X射线光电子能谱、反向光电子能谱、扫描隧道显微镜、原子力显微镜和磁力显微镜。非技术描述：该项目是关于有机半导体中自旋注入和驰豫的基础材料研究。该项目的成功可以加深对分子系统中与自旋相关现象的本质的理解，对未来信息技术的有机自旋电子学具有潜在的影响。这一影响还来自于对具有国际经验和领导能力的快速发展领域的下一代科学家的培训。该项目的一个主要重点是教育和培训交叉学科领域的科学家，包括有机电子材料、表面和界面分析、超快动力学和自旋电子学。该计划的重点是通过包括罗切斯特大学理工科女学生和高中生物理预科经验在内的计划增加女性的参与。该项目由电子和光子材料计划(EPM)和凝聚态物理计划(CMP)共同资助。

Technical Description: Research on organic spintronics has gained momentum in the past few years. An important advantage of organic materials is the intrinsically long spin-lifetime because of the small atomic numbers, resulting in less spin-orbit interaction. Strong organic magnetoresistance response as high as 300% has recently been reported. The roles of spin injection and carrier recombination in organic light emitting diodes have also been extensively observed. While the potential is high, there remain challenging fundamental issues, including the mechanisms governing spin injection and spin flip. It is well recognized that interfaces are critical in organic spintronics. The knowledge gap in understanding of the fundamental processes in organic spintronics must be bridged to realize its potential.The goal of this project is to investigate spin injection and relaxation dynamics to understand the underlying fundamental mechanisms important for the development of organic spintronics. The spin injection efficiency is investigated for the interface between various inorganic substrates and organic materials, and the spin relaxation dynamics are studied in organic semiconductor thin films. The primary tool for the investigation is spin-resolved photoemission spectroscopy, supported by other surface analytical techniques including ultraviolet and x-ray photoemission spectroscopy, inverse photoemission spectroscopy, scanning tunneling microscopy, atomic force microscopy, and magnetic force microscopy. Non-Technical Description: The project is on fundamental materials research of spin injection and relaxation in organic semiconductors. Success of the project can enhance the understanding of the nature of spin-related phenomena in molecular system, with potential impact on organic spintronics for future information technologies. The impact also comes from training of the next generation of scientists in a fast advancing field with international experience and leadership. A major focus of the project is educating and training scientists in an interdisciplinary field including organic electronic materials, surface and interface analysis, ultrafast dynamics, and spintronics. A strong emphasis of the program is on increasing participation of women through programs including University of Rochester Women in Science and Engineering and Pre-College Experience in Physics for high-school students.This project is co-funded by the Electronic and Photonic Materials Program (EPM) and the Condensed Matter Physics Program (CMP).