Graphene transparent conductors for tandem photovoltaic cells

硅光伏是世界上最令人兴奋和快速发展的行业之一。它不仅可以减少发电过程中有害的温室气体排放，而且是许多发展中国家电气化最具成本效益的解决方案。在这个项目中，学生将与一组专门的研究人员一起研究提高太阳能电池性能和降低成本的概念。目前光伏研究中最令人兴奋的领域之一是“串联电池”的发展。这个概念使用两个或更多的电池，堆叠在一起，以利用太阳光光谱中包含的大量能量。这种电池的一个关键部分是它们通过透明导电电极相互连接。该项目旨在演示静电电荷对石墨烯电导率的控制，目的是制造有效的石墨烯透明电极。它涉及将CVD石墨烯转移到特殊设计的介电基板上，该介电基板具有预先安排的金属电极结构，并且可以沉积/嵌入浓度的静电荷。所创建的设备将被测量以测试片电阻和霍尔迁移率，作为介电电荷浓度的函数。它们还将通过先进的电子显微镜、扫描开尔文探针显微镜、阻抗谱和光致发光进行表征，并通过控制与石墨烯相邻的界面层的合成来定制它们的特性。证明高导电性石墨烯作为带电介质的结果仍然是该领域的一个挑战，并且可以使其成为柔性电子产品和串联太阳能电池中的透明导体。到目前为止，由于缺乏合适的透明电极，这种装置的生产受到限制。因此，该项目属于EPSRC能源和ICT研究领域。该项目专注于开发这一突破性概念，并通过化学、固态物理和器件表征的先进方法将其应用于电子和界面材料领域。

Silicon photovoltaics is one of the most exciting and rapidly evolving industries worldwide. Not only can it reduce harmful greenhouse gas emissions from electricity generation, it is the most cost effective solution for electrification of many developing countries. In this project the student will work with a team of dedicated researchers on concepts to increase the performance and lower the cost of solar cells. One of the most exciting areas of research in photovoltaics at present is the development of "tandem cells". This concept uses two or more cells, stacked on each other, to exploit a larger amount of energy contained in the sunlight spectrum. A critical part of such cells is their interconnection via a transparent conducting electrode. This project aims to demonstrate the control of conductivity in graphene as a result of electrostatic charge with the purpose of making an effective graphene transparent electrode. It involves transfer of CVD graphene onto specially designed dielectric substrates, which have a pre-arranged metal electrode configuration, and can be deposited/embedded with a concentration of static charge. The created devices will be measured to test sheet resistance and hall mobility, as a function of dielectric charge concentration. They will be also be characterised via advanced electron microscopy, scanning Kelvin Probe microscopy, impedance spectroscopy, and photoluminescence, and their properties tailored by controlling the synthesis of interfacial layers adjacent to the graphene. Demonstrating highly conductive graphene as a results of a charged dielectric remains a challenge in the field, and can enable its use as a transparent conductor in flexible electronics and tandem solar cells. The production of such devices is, as of yet, limited by the lack of a suitable transparent electrode. As such, this project falls within the EPSRC Energy and ICT research areas. The project concentrates on developing such ground-breaking concept, and applying it to the field of electronic and interface materials, via advanced methods in chemistry, solid state physics, and device characterization.