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Collaborative Research: Predictive theory, synthesis and characterization of a new type of transparent conductor without doping

合作研究：新型无掺杂透明导体的预测理论、合成和表征

基本信息

批准号：
1806912
负责人：
Kenneth Poeppelmeier
金额：
$ 27万
依托单位：
Northwestern University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1806912&HistoricalAwards=false
关键词：
Collaborative Research Predictive theory synthesis

项目摘要

Non-technical description: Technologies such as photovoltaic solar cells, smart windows, light emitting diodes, touch-screen sensors, electronic papers, and flat panel displays require for their operation a critical component that is both an electrical conductor and optically transparent, the so-called transparent conductors. These compounds are unique, as transparency and conductivity are generally mutually exclusive properties of compounds. Indeed, optical transparency (as in window glass) is generally associated with electrical insulation, whereas electrical conductivity (such as in copper or gold) is generally associated with optically opaque metals. Known transparent conductors such as indium oxide doped with Sn are made by instilling conductivity in transparent insulators. The research team aims to develop a novel family of transparent conductors - metallic ceramics - by designing transparency in metals. This presents a new method to design optical properties as distinct from electronic properties. The approach has an exciting intellectual impact as it suggests a general approach for inverse design - starting from science-based design principles used as 'filters' for computational material selection, followed by identification of representative examples and then laboratory validation. The graduate students and postdocs of CU Boulder and Northwestern Universities are given exciting opportunities to participate in this cutting edge research effort.Technical description: Transparent conducting oxides are paradoxical materials that form the basis of modern day technologies, such as touch screens, flat panel displays, solar panels, etc. The current method of choice for discovering new transparent conductors have relied on heavily doping transparent insulators until they become conducting. Unfortunately, wide band gap materials are intrinsically resistant to doping of charges because of the existence of so-called 'doping bottlenecks'. Namely, the introduction of a high concentration of free carriers into insulators generally leads to the spontaneous formation of structural defects with polarity that compensate that of the intentional doping. Consequently, the progress in finding and optimizing such technologically critical transparent conducting oxide materials has been frustratingly slow. The research team proposes an opposite, and likely more fruitful alternative of designing transparency in metals by looking for compounds that obey a set of 'design principles' with specific band structures. The design rules for such intrinsic transparent conductors are: (i) identify a compound with metallic band structure; such that (ii) it has low plasma frequency and (iii) low inter-band optical absorption across the Fermi level, and (iv) apply synthesis and characterization to the 'best of class' compounds, here Ba-Nb-O. The most visible advantage of metallic transparent conductors is that their conductivity comes from their high, indigenous carrier concentration. The complex theory-experimental approach in the proposal enables more efficient progress as alternative to the previously used trial-and-error method.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：诸如光伏太阳能电池、智能窗户、发光二极管、触摸屏传感器、电子纸和平板显示器等技术的运行都需要一个关键组件，该组件既是电导体，又是光学透明的，即所谓的透明导体。这些化合物是独一无二的，因为透明度和导电性通常是化合物相互排斥的性质。事实上，光学透明性（如窗玻璃）通常与电绝缘有关，而导电性（如铜或金）通常与光学不透明的金属有关。已知的透明导体，如掺杂锡的氧化铟，是通过在透明绝缘体中注入导电性而制成的。研究小组的目标是通过设计金属的透明度来开发一种新型的透明导体——金属陶瓷。这提出了一种设计光学性质有别于电子性质的新方法。该方法具有令人兴奋的智力影响，因为它提出了逆设计的一般方法-从基于科学的设计原则开始，作为计算材料选择的“过滤器”，然后识别代表性示例，然后进行实验室验证。科罗拉多大学博尔德分校和西北大学的研究生和博士后都有机会参与这项前沿研究工作。技术描述：透明导电氧化物是一种矛盾的材料，它构成了现代技术的基础，如触摸屏、平板显示器、太阳能电池板等。目前发现新型透明导体的方法依赖于大量掺杂的透明绝缘体，直到它们具有导电性。不幸的是，由于所谓的“掺杂瓶颈”的存在，宽带隙材料本质上是不允许掺杂电荷的。也就是说，在绝缘体中引入高浓度的自由载流子通常会导致自发形成具有极性的结构缺陷，以补偿故意掺杂的结构缺陷。因此，寻找和优化这种技术上至关重要的透明导电氧化物材料的进展一直令人沮丧地缓慢。研究小组提出了一个相反的，可能更富有成效的替代方案，即通过寻找具有特定能带结构的遵循一套“设计原则”的化合物来设计金属的透明度。这种本征透明导体的设计原则是：(i)确定具有金属带结构的化合物；这样（ii）它具有低等离子体频率和（iii）在费米能级上的低带间光吸收，以及（iv）适用于“同类最佳”化合物的合成和表征，这里是Ba-Nb-O。金属透明导体最明显的优点是其导电性来自于其高的固有载流子浓度。该提案中复杂的理论-实验方法可以替代以前使用的试错方法，从而实现更有效的进展。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。