Spin Response in Organic Semiconductors with Tuned Spin-Orbit Coupling

该项目由材料研究部的电子和光子材料(EPM)和凝聚态物质物理(CMP)计划联合资助。非技术描述：这个项目是关于新合成的有机聚合物的物理性质，这些有机聚合物在聚合物链上以不同的间隔含有铂(铂)原子。链内铂原子大大增强了聚合物链中电子的自旋和轨道角动量之间的耦合。这导致了强烈的红色磷光发射，除了已知的更常见的没有自旋轨道耦合的高分子链的蓝色荧光发射之外。这两种发光机制的结合创造了白光，可以用于新开发的白色有机发光二极管，未来可能会取代普通灯泡。通过对这些聚合物的光学、电学和磁学研究，探索了一些基本的科学问题，这些问题可能对这些材料的潜在应用产生重要的影响。此外，将大量实验技术整合到主要研究人员的研究小组中，有助于有效地教育参与这一高度跨学科研究项目的研究生和本科生。这个项目的教育方面特别开放与犹他大学科学学院的ACCESS项目合作，该项目旨在加强女性对自然科学的参与。技术描述：这个研究项目是研究新合成的具有大自旋-轨道耦合的自旋泵浦、自旋注入和自旋操纵所揭示的自旋排列载流子响应。在这些聚合物中，铂原子沿着链以不同的间隔插入到有机构建块中，从而有效地调节了聚合物的自旋-轨道耦合。这项研究使用了各种新颖的光学、磁光和电学测量技术。利用三种有效的自旋极化技术对铂聚合物中的自旋取向载流子进行极化，这些技术包括：铁磁电极注入自旋、铁磁衬底中自旋波抽运自旋和圆偏振光吸收光学自旋取向。研究了以下过程：利用磁光克尔效应和磁电致发光在这些聚合物中注入和输运自旋排列的载流子；各种铁磁自旋注入器中自旋波泵浦产生的自旋电流；以及光致自旋排列的三重态激子。这些研究有助于理解控制有机自旋装置自旋响应的物理过程，并有可能使其性能发生革命性变化。

This project is jointly funded by the Electronic and Photonic Materials (EPM) and Condensed Matter Physics (CMP) Programs, both in the Division of Materials Research. Non-technical Description: This project is on the physical properties of newly synthesized organic polymers that contain platinum (Pt) atoms at different intervals along the polymer chain. The intrachain Pt atoms substantially enhance the coupling between the spin and the orbital angular momentum of electrons in the polymer chain. This leads to a strong red phosphorescence emission, in addition to the blue fluorescence emission known from more common polymer chains without spin-orbit coupling. The combination of both types of emission mechanisms creates white light that can serve in newly developed white organic light emitting diodes, which may replace regular bulbs in the future. Through optical, electrical and magnetic studies of these polymers, a number of fundamental scientific questions are explored that can have important ramifications on potential applications of these materials. In addition, the integration of the large arsenal of experimental techniques within the research groups of the principal investigators serves to efficiently educate graduate and undergraduate students involved in this highly interdisciplinary research project. The educational aspects of this project are in particular open to collaboration with the ACESS program at College of Science of the University of Utah, which aims to enhance the involvement of women in natural sciences.Technical Description: This research project is to study the spin-aligned carrier response as revealed by spin-pumping, spin-injection and spin-manipulation in newly synthesized pi-conjugated polymers with large spin-orbit coupling. In these polymers, Pt atoms are inserted into the organic building blocks at different intervals along the chain, which effectively tune the polymer spin-orbit coupling. The research uses a variety of novel optical, magneto-optical and electrical measurement techniques. The spin aligned carriers in Pt-polymers are polarized using the three effective techniques of spin polarization that include: spin injection by ferromagnetic electrodes, spin pumping by spin-waves in ferromagnetic substrates, and optical spin alignment by circularly polarized light absorption. The following processes are investigated: spin aligned carrier injection and transport in these polymers using the magneto-optic Kerr effect and magneto-electroluminescence; spin-current induced by spin-wave pumping in various ferromagnetic spin injectors; and photo-induced spin aligned triplet excitons. These studies contribute to the understanding of the physical processes that govern the spin response in organic spin devices, and have the potential to revolutionize their performance.