CAREER: Plasmon-mediated photo-absorption and carrier recombination dynamics in semiconductor/metal hybrid nano-systems

职业：半导体/金属混合纳米系统中等离激元介导的光吸收和载流子复合动力学

• 批准号: 1352507
• 负责人: Marcus Jones
• 金额: $ 53.31万
• 依托单位: University of North Carolina at Charlotte
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1352507&HistoricalAwards=false
• 关键词: CAREER; Plasmon; mediated; photo; absorption

In this project, funded by the Chemistry Division's Macromolecular, Supramolecular and Nanochemistry Program, Marcus Jones from the University of North Carolina at Charlotte is investigating how the interactions between nano-sized quantum dots and metal particles in the presence of light can be used to enhance the function of optoelectronic devices such as solar cells and light-emitting diodes (LEDs). Quantum dots are tiny semiconductors whose color depends on their size: larger particles appear redder than smaller ones. Metal nanoparticles can act as miniature antennas that channel light energy into or out of the quantum dots. This research program aims to unravel the complex interplay between nanoscale metals and semiconductors that could potentially enable technological advances such as thinner, more efficient solar cells and brighter LEDs. This work is also being integrated into a teaching and outreach program, which, in collaboration with the Charlotte Teachers' Institute, aims to educate local schoolteachers about the amazing world of nanoscale science and facilitates their participation in short term projects where they can do cutting-edge research for themselves. Inspired by the activities of the NSF ADVANCE initiative at UNC Charlotte, Marcus is also organizing a seminar series at UNC Charlotte, aimed at improving the retention of women in science, at which female science professionals are invited to discuss the challenges and rewards of being a woman in science.This research program aims to develop our understanding of the photo-absorption and emission effects caused by resonant coupling between excitons in quantum dots and surface plasmon modes in nanostructured metals. Acting like local antennae, surface plasmon resonances can enable efficient coupling of electromagnetic energy into or out of a chromophore. This can manifest as increased photoluminescence intensity, which is ascribed to either increased photo-absorption, or radiative recombination. The ability of coupled surface plasmon modes to capture and concentrate electromagnetic energy presents a tremendous opportunity to enhance the role of quantum dots in light harvesting or LED applications by improving multi-exciton generation yields, increasing biexciton emission efficiencies and eliminating fluorescence blinking. Unlike previous studies, this work is primarily focused towards understanding the effects of plasmonic coupling on the photo-absorption and carrier recombination rates of multi-excited quantum dots. A combination of single particle and newly developed ensemble techniques is being used to distinguish multi-exciton fluorescence dynamics occurring in fabricated hybrid nanosystems that have been designed to enable good control over exciton-plasmon interactions. Successful completion of the proposed research tasks will (i) establish the dependence of photo-absorption and radiative recombination rates on the distance between semiconductor and metal nanoparticles; (ii) resolve effects due to changes in quantum dot size, shape and composition; and (iii) identify the differences between photo-absorption and emission enhancements induced in single exciton versus charged and multi-exciton states.

在这个项目中，由化学部的大分子，超分子和纳米化学计划资助，来自夏洛特的北卡罗来纳州大学的Marcus Jones正在研究纳米尺寸的量子点和金属颗粒之间的相互作用在光的存在下如何可以用来增强光电器件的功能，如太阳能电池和发光二极管（LED）。量子点是微小的半导体，其颜色取决于它们的大小：较大的粒子比较小的粒子看起来更红。金属纳米颗粒可以充当微型天线，将光能导入或导出量子点。该研究计划旨在揭示纳米级金属和半导体之间复杂的相互作用，这些相互作用可能会推动技术进步，例如更薄，更高效的太阳能电池和更亮的LED。这项工作也被整合到一个教学和推广计划中，该计划与夏洛特教师研究所合作，旨在教育当地教师了解纳米科学的神奇世界，并促进他们参与短期项目，在那里他们可以为自己做尖端研究。受到NSF ADVANCE倡议在夏洛特夏洛特活动的启发，马库斯还在夏洛特夏洛特组织了一系列研讨会，旨在提高女性在科学领域的保留率，会上，女性科学专业人士被邀请讨论作为一名科学女性所面临的挑战和回报。该研究项目旨在加深我们对照片的理解-量子点中激子和纳米结构金属中表面等离子体激元模式之间的共振耦合引起的吸收和发射效应。表面等离子体共振就像局部天线一样，可以使电磁能有效地耦合到发色团中或从发色团中耦合出来。这可以表现为增加的光致发光强度，其归因于增加的光吸收或辐射复合。耦合的表面等离子体激元模式捕获和集中电磁能的能力提供了巨大的机会，以通过提高多激子产生产率、增加双激子发射效率和消除荧光闪烁来增强量子点在光捕获或LED应用中的作用。与以前的研究不同，这项工作主要集中在了解等离子体耦合对多激发量子点的光吸收和载流子复合率的影响。单粒子和新开发的合奏技术的组合被用来区分多激子荧光动力学发生在制造的混合纳米系统，已被设计为能够很好地控制激子-等离子体相互作用。成功完成拟议的研究任务将（i）建立光吸收和辐射复合率对半导体和金属纳米颗粒之间距离的依赖性;（ii）解决由于量子点大小，形状和成分变化而产生的影响;以及（iii）确定单激子与带电和多激子状态引起的光吸收和发射增强之间的差异。