DMREF: Collaborative Research: Materials design of correlated metals as novel transparent conductors

非技术描述：透明导体是影响社会的许多技术的关键组成部分，包括太阳能电池、触摸屏、平板显示器、发光二极管和激光器。寻找在可见光谱中结合高导电性和优异光学透明度的材料已被证明是具有挑战性的：金属通常是良好的导体，但反射而不是传输可见光，而像玻璃这样的绝缘体是高度透明的，但不携带电流。该项目的目标是追求一种非传统的范例，在项目团队成员之前的工作中开发，发现和开发新的透明导电材料，这种材料基于地球丰富的元素，表现出更好的性能，并且可以比长期存在的工业标准氧化铟锡（ITO）成本更低。理论分析结合材料性能测量和计算数据库的挖掘与候选材料结构和性能的预测模拟，将与实验室合成、表征和优化真实材料的努力紧密结合。在材料基因组计划的背景下，在全国范围内协调努力，加速先进材料的发现、开发和部署，在项目过程中开发的材料设计理论和实验的整合工具和技术将提供给社区，以推动更广泛的材料设计挑战的进展。透明导体发展的突破将推动能源生产、照明和被动式建筑设计的绿色技术。技术描述：将透明和高导电性相矛盾的特性结合起来的传统范例是大量掺杂宽带隙。因此透明？增加半导体的导电性。新范例的想法是使金属具有光学透明度，而不是使透明半导体更具导电性。这可以通过相关效应增加电子有效质量来实现，这降低了可见光范围内的金属反射率，目标系统的带间跃迁高于可见光范围。发现新的透明导体的设计空间跨越了广泛的家族，包括相关氧化物，层状硫属化合物，羟基和金属间化合物。将采用分层的三级搜索方法。首先，候选材料将在可用的材料设计空间中使用简单适用的限定条件进行预筛选，然后在密度泛函理论（DFT）水平上对晶体结构、电子带和与光和电输运性质相关的数量进行高通量第一性原理计算。在第三个层次，将在密度泛函平均场理论（DMFT）中研究相关效应，以完善较低层次的搜索标准，并确定最有前途的系统进行进一步研究。在实验室中，这些候选材料的电输运和光学性质的合成和表征以及与理论预测的比较将有助于改进设计原则和扩展可用于技术应用的透明导电材料集。

NON-TECHNICAL DESCRIPTION: Transparent conductors are a critical component in many technologies affecting society, including solar cells, touch screens, flat panel displays, light emitting diodes and lasers. Finding materials that combine high electrical conductivity with excellent optical transparency in the visible spectrum has proved challenging: metals typically are good conductors but reflect rather than transmit visible light, while insulators like glass are highly transparent but do not carry an electrical current. The goal of this project is to pursue an unconventional paradigm, developed in previous work by members of the project team, to discover and develop new transparent conducting materials based on earth-abundant elements that exhibit substantially better performance and can be made with lower cost than the long-standing industry-standard indium-tin-oxide (ITO). Theoretical analysis combining mining of databases of materials property measurements and computations with predictive simulations of the structure and properties of candidate materials will be closely integrated with efforts in the laboratory to synthesize, characterize and optimize real materials. In the context of the Materials Genome Initiative coordinating efforts across the nation to accelerate the discovery, development and deployment of advanced materials, tools and techniques for integration of theory and experiment in materials design that are developed in the course of the project will be made available to the community to advance progress in broader materials design challenges. Breakthroughs in the development of transparent conductors will advance green technologies for energy generation, lighting, and passive building designs.TECHNICAL DESCRIPTION: The conventional paradigm to combine the contradicted properties of transparency and high electrical conductivity is to heavily dope a wide band gap ? thus transparent ? semiconductor to increase its electrical conductivity. Rather than making a transparent semiconductor more conductive, the idea of the new paradigm is to make a metal optically transparent. This can be done by increasing the electron effective mass by correlation effects, which reduces the metal reflectivity in the visible range, in targeted systems for which interband transitions are above the visible range. The design space for the discovery of new transparent conductors spans a wide range of families, including correlated oxides, layered chalcogenides, pnictides, and intermetallic compounds. A hierarchical three-level search approach will be pursued. First, material candidates will be pre-screened in the available materials design space using simple-to-apply qualifier criteria, followed by high-throughput first-principles computations of crystal structure, electronic bands, and quantities related to optical and electrical transport properties at the level of density functional theory (DFT). At the third level, correlation effects will be studied within density functional mean field theory (DMFT) to refine the lower level search criteria and identify the most promising systems for further investigation. In the laboratory, synthesis and characterization of the electrical transport and optical properties of these candidate materials and comparison with theoretical predictions will aid in the refinement of design principles and the expansion of the set of transparent conducting materials available for technological applications.