Thin films for silicon-based tandem photovoltaics 1=Energy 2=Solar Technology

超过90%的光伏太阳能电池是由晶体硅制成的，随着全球安装量接近太瓦水平，这一市场份额正在增加。最好的单结硅电池的效率高达26.7%，而记录在案的电池正在接近硅电池的最高效率29.4%。通过在硅基太阳能电池上沉积或安装更宽的带隙半导体来形成串联结构，可以超过这个限制，从而能够超过35%的效率。这样的设备架构非常及时，如果成功，将通过可再生能源对全球能源生产产生重大影响。在硅上放置各种薄膜半导体（如钙钛矿、碲化镉、CIGS）是人们关注的焦点，但对与硅的界面关注较少。这个博士项目将解决支撑硅和薄膜半导体之间界面的基础科学，以加速串联电池的发展。目的是利用原子层沉积（ALD）开发超薄钝化膜（< 1nm），当应用于半导体表面时，其表现出优异的热稳定性和电稳定性。目标是发展对原子尺度钝化机制的基本理解，以及如何操纵过程以实现最佳的长期热学和电学性能。然后将在一系列环境中应用所开发的电影；主要是硅光伏（重点是串联），但也有其他应用，如锂离子电池阳极。

More than 90% of photovoltaic solar cells are made from crystalline silicon, and this market share is increasing as worldwide installations approach the terawatt level. The best single-junction silicon cells have efficiencies of up to 26.7%, and record cells are closing in on silicon's maximum efficiency of 29.4%. This limit can be exceeded by depositing or mounting a wider bandgap semiconductor on top of the silicon-based solar cell to form a tandem configuration, which are capable of exceeding efficiencies of 35%. Such device architectures are very timely, and if successful will have a significant impact on global energy production through renewable sources.Much attention has focused on placing a variety of thin film semiconductors onto silicon (e.g. perovskites, CdTe, CIGS), but less attention has been paid on the interface with the silicon. This PhD project will address the fundamental science underpinning the interface between the silicon and the thin film semiconductor to accelerate the development of tandem cells. The aim is to develop ultra-thin passivation films (< 1 nm) using atomic layer deposition (ALD), which exhibit excellent thermal and electrical stability when applied to semiconductor surfaces. The objective will be to develop a fundamental understanding of the passivation mechanism at the atomic scale and how processes can be manipulated in order to achieve optimal long-term thermal and electrical properties. The films developed will then be applied in a range of contexts; mainly silicon photovoltaics (with a focus on tandems), but also on other applications such lithium ion battery anodes.