• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Exploring ultrafast dynamics of excitons and multiexcitons in 'giant' nanocrystal quantum dots.
【24h】

Exploring ultrafast dynamics of excitons and multiexcitons in 'giant' nanocrystal quantum dots.

机译：探索“巨型”纳米晶体量子点中激子和多激子的超快速动力学。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In this work, we have performed extensive time resolved photoluminescence (PL) studies to further the understanding of charge dynamics in semiconductor nanocrystal quantum dots (QDs). Recent developments in QD synthesis have introduced a new set of QD known as "giant" quantum dots (gQDs) that consist of a CdSe core coated with up to 19 monolayers of a CdS shell. The thick shell layer is grown using a SILAR method resulting in a defect free, alloyed CdSe/CdS interface. This has been attributed to gQDs exhibiting excellent optical properties such as high excitonic quantum yield (QY), prolonged photostability and inhibition of flourescence intermittency ("blinking"), which is regularly observed in conventional QDs. In gQDs, however, owing to unique fabrication methods and material selection, the Auger process is strongly suppressed resulting in efficient radiative recombination of photogenerated excitons as well as high PL QY of charged excitonic and multiexcitonic species. We perform extensive single gQDs studies that establish the role played by gQD shell thickness and core size in governing their optical properties. It is found that both the core and shell dimensions can be tuned in order to achieve the smallest gQDs with the highest vii Auger suppression resulting in photostable dots with high QYs. Next, we perform a study of multiexcitonic species in gQDs that are encapsulated in an insulating SiO2shell. These silica-coated gQDs exhibit strong PL from charged excitons, biexcitons as well as triexcitons. This observation has led to an accurate description of excitonic and multiexcitonic behavior which is modeled using a statistical scaling approach. As a demonstration of the practical applicability of gQDs, energy transfer of excitons as well as multiexcitons to different substrates is studied. Finally, a back gated silicon nanomembrane FET device is discussed that exhibits a large photocurrent increase when sensitized with QDs.
机译：在这项工作中，我们进行了广泛的时间分辨光致发光（PL）研究，以进一步了解半导体纳米晶体量子点（QD）中的电荷动力学。 QD合成的最新发展引入了一套称为“巨型”量子点（gQD）的新QD，该量子点由涂覆有多达19个CdS壳单层的CdSe核组成。使用SILAR方法生长厚壳层，从而形成无缺陷的CdSe / CdS合金界面。这归因于在常规QD中经常观察到的gQD具有出色的光学特性，例如高激子量子产率（QY），延长的光稳定性和抑制荧光间歇性（“闪烁”）。然而，在gQD中，由于独特的制造方法和材料选择，俄歇过程受到了强烈抑制，从而导致光生激子的有效辐射复合以及带电激子和多激子物种的高PL QY。我们进行了广泛的单个gQD研究，这些研究确定了gQD壳厚度和核尺寸在控制其光学性能方面所起的作用。发现可以调整核和壳的尺寸，以实现具有最高vii Auger抑制的最小gQD，从而得到具有高QY的光稳定点。接下来，我们对封装在绝缘SiO2壳中的gQD中的多激子物种进行研究。这些二氧化硅涂层的gQD在带电的激子，双激子以及三激子中均表现出较强的PL。该观察结果导致了对激子和多激子行为的准确描述，这是使用统计定标方法建模的。为了证明gQD的实际适用性，研究了激子以及多激子向不同底物的能量转移。最后，讨论了背栅硅纳米膜FET器件，当用QD敏化时，该器件显示出大的光电流增加。

著录项

  • 作者

    Sampat, Siddharth.;

  • 作者单位

    The University of Texas at Dallas.;

  • 授予单位 The University of Texas at Dallas.;
  • 学科 Quantum physics.;Materials science.;Optics.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 107 p.
  • 总页数 107
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 康复医学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号