Spectroscopy of excitions in single nanorods

具有各向异性光学和电子特性的半导体纳米结构为纳米器件的自底向上设计和混合光主动/被动纳米结构的光学功能化提供了重要的材料类别。该项目旨在调查和理解单纳米棒中激子基本激发的维度和方向依赖性，作为使用它们的先决条件，例如，用于应用目的和基础物理的基于纳米棒的复合物。重点研究了纤锌矿型纳米棒中特有的高度线极化发射。以温度、激发能、泵浦功率、纳米棒尺寸和形状、ZnS壳层厚度和形状、纳米棒环境和生长机制为外部参数，在单纳米棒水平上研究了胶体CdSe纳米棒中激子的对称性和波函数、激子精细结构、辐射寿命、态密度以及与其他基本激发（声子、带电激子、双激子）的相互作用。为了了解具有不同对称能级的高极化取向发射体（纳米棒）在功能纳米系中的具体作用，我们研究了更复杂结构的纳米棒，如排列纳米棒系、纳米棒/染料和纳米棒/金属丝配合物，并确定了配合物内部的电子耦合、能量转移、光转换和相互激发。

Semiconductor nanostructures with anisotropic optical and electronical properties present an important material class for bottom-up design of nanodevices and optical functionalization of hybrid optically active/passive nanostructures. This project is aimed at the investigation and understanding of dimensionality and directional dependencies of excitonic elementary excitations in single nanorods as a prerequisite for using them, e.g., in nanorod-based complexes for application purposes and fundamental physics. The focus is on the peculiar high degree of linearly polarized emission in wurtzite-type nanorods. The symmetries and wave functions of excitons in colloidal CdSe nanorods, the excitonic fine structures, the radiative lifetime, the density of states as well as interaction with other elementary excitations (phonons, charged excitons, biexcitons) will be studied by spectroscopy on a single nanorod level with temperature, excitation energy, pump power, nanorod size and shape, ZnS shell thickness and shape, nanorod environment and growth regimes as external parameters. To understand the specific action of highly polarized, oriented emitters with close-lying energy states of different symmetry (the nanorods) in functional nanoensembles, we study nanorods in more complex structures, such as ensembles of aligned nanorods, nanorod/dye and nanorod/metal wire complexes and determine electronic coupling, energy transfer, light conversion and mutual excitation inside the complexes.