Understanding the electronic structure landscape in wide band gap metal halide perovskites

了解宽带隙金属卤化物钙钛矿的电子结构景观

• 批准号: EP/X039285/1
• 负责人: Alexandra Ramadan
• 金额: $ 50.83万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX039285%2F1
• 关键词: Understanding; electronic; structure; landscape; wide

To mitigate the worst impacts of climate change there is an immediate global need for clean, secure, and efficient energy generation. Solar energy generation through photovoltaics has the potential to produce the electricity required for a growing population which is cheap and produces significantly lower carbon emissions than conventional power generation technologies. Metal halide perovskites (MHPs) have emerged in recent years as an exciting new photovoltaic technology both on their own and in combination with exciting solar technologies in tandem photovoltaics. The latter, wherein two or more solar cells are coupled to overcome thermodynamic limits, will produce photovoltaics with power conversion efficiencies > 30 %. As the implementation of photovoltaics hinges on their cost and this is directly related to their power conversion efficiencies, tandem photovoltaics offer considerable potential for lowering the cost of photovoltaic implementation.Wide band gap MHPs (> 1.7 eV) are essential for perovskite tandem photovoltaics however they have undergone less investigation than their narrow band gap counterparts resulting in their performance being constrained far below the theoretical limit. There is a lack of understanding of the electronic structure of these materials which translates directly into significant voltage losses in photovoltaic devices. This has led to qualitative selection of charge transport layers in device design and an inability to fine tune the energy level alignment at these interfaces. The difficulty in understanding these systems is due, in large part, to the chemical complexity of these systems. The highest performing wide band gap MHPs are mixed cation, mixed halide systems and their complexity makes studying their electronic structure incredibly challenging. To overcome these challenges this project will build a holistic overview of the electronic structure of wide band gap MHPs, using experimental model systems and ab-initio materials modelling to create theoretical models which can be used to understand experimental measurements of device relevant systems. Single crystals of MHPs will be used as model systems and studied using photoelectron and photophysical spectroscopies to probe their electronic structure. High resolution atomic force microscopy techniques will be adapted to non-destructively image the structure of the crystals and provide information on the structural defects present on the surfaces. Together these measurements will facilitate the development of models which will provide new insights into the fundamental electronic structure of MHPs. These models will be applied to photovoltaic device architectures to determine the origin of voltage losses and a quantitative series of recommendations for overcoming these losses will be produced. Understanding the electronic structure of MHP materials is critical in ensuring the successful commercialisation of technologies based on these exciting new semiconductors. This research will not only facilitate the continued development of photovoltaics based on these materials but will contribute to our fundamental understanding of this new class of semiconductor materials.

为了减轻气候变化的最严重影响，全球对清洁，安全和有效的能源产生的需求直接需要。通过光伏发电的太阳能产生有可能生产不断增长的人口所需的电力，该人口价格便宜，并且比传统发电技术产生的碳排放量要低得多。近年来，金属卤化物钙钛矿（MHP）已成为一种令人兴奋的新型光伏技术，并且与串联光伏的令人兴奋的太阳能技术结合在一起。后者，其中两个或多个太阳能电池耦合以克服热力学限制，将产生具有功率转换效率> 30％的光伏电池。由于光伏的实施取决于其成本，这与他们的功率转换效率直接相关，因此串联光伏具有降低光伏实施成本的相当大潜力理论上限。缺乏对这些材料的电子结构的了解，这些材料直接转化为光伏设备中的明显电压损耗。这导致了在设备设计中定性选择电荷传输层的选择，并且无法微调这些接口处的能级对齐。理解这些系统的困难很大程度上是由于这些系统的化学复杂性。性能最高的宽带间隙MHP是混合阳离子，混合卤化物系统，其复杂性使研究其电子结构令人难以置信的挑战。为了克服这些挑战，该项目将使用实验模型系统和AB-Initio材料建模来建立整体概述宽带隙MHP的电子结构，以创建理论模型，该模型可用于了解设备相关系统的实验测量。 MHP的单晶将用作模型系统，并使用光电子和光物理光谱镜进行研究以探测其电子结构。高分辨率原子力显微镜技术将适应非破坏性图像晶体的结构，并提供有关表面上存在的结构缺陷的信息。这些测量结果将促进模型的开发，这些模型将为MHP的基本电子结构提供新的见解。这些模型将应用于光伏设备架构，以确定电压损耗的起源，并将产生一系列克服这些损失的建议。了解MHP材料的电子结构对于确保基于这些令人兴奋的新半导体的技术的成功商业化至关重要。这项研究不仅将促进基于这些材料的光伏发展的持续发展，而且将有助于我们对这类新型半导体材料的基本理解。