Lattice Dynamics and Charge Transport in Metastable Ternary Nitrides for Solar Energy Conversion

用于太阳能转换的亚稳态三元氮化物中的晶格动力学和电荷传输

• 批准号: 452445233
• 负责人: Dr. Franziska Simone Hegner
• 金额: --
• 依托单位: Arbeitsgruppe Theorie funktionaler Energiematerialien
• 依托单位国家: 德国
• 项目类别: WBP Position
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/452445233?language=en
• 关键词: Lattice; Dynamics; Charge; Transport; Metastable

In view of dramatically rising global temperatures and increasing energy demand worldwide, it becomes more urgent than ever to find renewable and clean energy sources. Out of those, solar power is paramount; even in the coldest regions on Earth, there is more than enough to meet society’s energy needs. The problem lies in harvesting this abundant solar energy and making it accessible to the people. The proposed project “Lattice Dynamics and Charge Transport in Metastable Nitrides for Solar Energy Conversion” tackles this challenge by achieving fundamental understanding of a new class of materials, metastable nitrides, that will have a large impact on next-generation solar energy devices. By means of computational and experimental methods, this project addresses their mechanisms of dynamical stabilisation and charge transport as well as their mutual interplay. This is not only crucial for photovoltaic applications but will also lead to new insights into the underlying physics of metastable materials. Metastable materials present a relatively unexplored phase space that provides new design opportunities as well as an ideal platform for exciting fundamental research.The representative copper tantalum nitride CuTaN2 will be first investigated as it shows large promises for applications in solar cells. Apart from its extremely efficient light absorption, it is experimentally stable up to 250°C, which is ideal for the proposed study and real device implementation. From the gained knowledge of lattice dynamics and charge transport in CuTaN2, relationships between those fundamental mechanisms and the metastability of the material will be derived. These concepts will then be generalised to a much broader pool of metastable nitrides, specifically those that do not contain rare elements. Particularly promising are (Sn1-xTix)3N4 and CaxZn2-xN2, which were recently synthesised for the first time. They exhibit desirable optoelectronic properties while being composed of Earth-abundant elements. With the methodology established for CuTaN2, we will investigate their basic properties, which will allow us to draw comparisons between the different nitride materials and to assess the universality of the underlying mechanisms.Taken together, the specific research objectives are: (i) to provide a detailed theoretical and experimental account on the structural, electronic, and optical properties of CuTaN2, (ii) to comprehensively investigate its lattice dynamics and anharmonic effects, (iii) to study charge carrier transport and how it is influenced by dynamical nuclear motions, and (iv) to apply the established protocol and to assess the relevance of our models to other metastable nitride materials.All in all, the proposed approach will pave the path towards a new generation of environmentally benign, abundant, and inexpensive light-absorbing semiconductor materials and, thus, towards finding better and more efficient solutions for harvesting solar light.

鉴于全球气温急剧上升和全球能源需求不断增加，寻找可再生和清洁能源变得比以往任何时候都更加紧迫。其中，太阳能是最重要的；即使在地球上最寒冷的地区，太阳能也足以满足社会的能源需求。问题在于如何收获这种丰富的太阳能，并让人们能够接触到它。拟议的“用于太阳能转换的亚稳态氮化物中的晶格动力学和电荷传输”项目通过对将对下一代太阳能设备产生重大影响的一类新材料--亚稳态氮化物--的基本了解来解决这一挑战。本课题通过计算和实验相结合的方法，研究了它们的动力学稳定和电荷输运机制，以及它们之间的相互作用。这不仅对光伏应用至关重要，而且还将对亚稳态材料的基本物理产生新的见解。亚稳态材料提供了一个相对未知的相空间，提供了新的设计机会，也是一个激动人心的基础研究的理想平台。具有代表性的氮化钽铜铜将首先被研究，因为它在太阳能电池中显示出巨大的应用前景。除了其极高的光吸收效率外，它在实验上的稳定性高达250°C，这是拟议的研究和实际设备实施的理想选择。根据所获得的CuTaN_2中晶格动力学和电荷输运的知识，这些基本机制与材料的亚稳性之间的关系将被推导出来。然后，这些概念将被推广到更广泛的亚稳氮化物池中，特别是那些不含稀有元素的亚稳氮化物。特别有希望的是最近首次合成的(Sn1-xTix)3N4和CaxZn2-xN2。当它们由富含地球的元素组成时，表现出令人满意的光电性能。利用为CuTaN_2建立的方法，我们将研究它们的基本性质，这将使我们能够在不同的氮化物材料之间进行比较，并评估潜在机制的普遍性。总的来说，具体的研究目标是：(I)提供关于CuTaN_2的结构、电子和光学性质的详细的理论和实验解释，(Ii)全面研究其晶格动力学和非谐效应，(Iii)研究电荷载流子输运以及它是如何受到动态核运动的影响的，以及(Iv)应用所建立的方案并评估我们的模型与其他亚稳态氮化物材料的相关性。总之，建议的方法将为新一代环境友好、丰富和廉价的吸光半导体材料铺平道路，从而找到更好、更有效的太阳能采集解决方案。