Correlation of growth, structure, optical and electronic properties of novel Nb3O7(OH) and Nb2O5 nanostructures

一维单晶纳米结构金属氧化物电极具有为电荷载流子创建有效路径的优点。然而，这些结构中出现的缺陷和不同的晶体学修饰会影响它们在混合和染料敏化太阳能电池、电池或（光）催化等应用中的性能。该项目将重点关注新型Nb3O7（OH）和Nb2O5纳米结构，并将其与成熟的TiO 2进行比较。铌氧化物系统很少被详细阐述，即使它们具有很高的应用潜力。接下来的详细分析，特别关注的是控制生长和生长条件对铌氧化物系统的特性的影响。对于金属氧化物纳米结构，理解和控制电荷载流子迁移率以允许在器件中定制应用将是至关重要的。在这方面，该项目侧重于分析晶界和结晶度对电荷传输和复合的影响，因为这些过程由结构缺陷引起，可能主导光学和电子性能。通过改变生长条件，更好地理解导致这种缺陷的机制将允许控制和限制缺陷的形成，正如我们之前对TiO 2所示的那样。高分辨率透射显微镜研究与光学和电子表征方法相结合，使我们能够对晶体生长，结构，电荷传输等物理现象以及这些特性之间的相关性有基本的了解。

One-dimensional single crystalline nanostructured metal oxide electrodes have the advantage of creating efficient pathways for charge carriers. However, defects occurring in these structures and different crystallographic modifications affect their performance in applications such as hybrid and dye-sensitized solar cells, batteries or (photo-)catalysis. This project will focus on novel Nb3O7(OH) and Nb2O5 nanostructures and compare them with the well-established TiO2. The niobium oxide systems have rarely been elaborated, even though they have a high potential for applications. Next to a detailed analysis, special focus will be put on the controlled growth and the influence of the growth conditions on the characteristics of the niobium oxide systems. For the metal oxide nanostructures it will be essential to understand and control the charge carrier mobility in order to allow tailored application in devices. In this regard, this project focusses on the analysis of the effects of grain boundaries and the crystallinity on charge transport and recombination as these processes caused by structural defects might dominate the optical and electronic properties. By varying the growth conditions, better understanding of the mechanisms leading to such defects will allow to control and limit the formation of defects as it has been shown previously by us for TiO2. The combination of high-resolution transmission microscopy studies and optical and electronic characterization methods enables us to obtain a fundamental understanding of the physical phenomena of crystal growth, structure, charge transport, etc. and the correlation between these properties.