Rational Design of High-performance Semiconductors based on Inorganic Perovskites Containing Bismuth

非技术描述：具有理想电子结构的高性能氧化物半导体的发展直接影响到许多与能源相关的应用，包括光伏、大功率电子和光催化。该项目采用理论和实验相结合的方法，快速发现以钙钛矿型氧化物和含铋氮氧化物为基础的新型高性能半导体。这一系列前景看好的化合物代表着一个巨大的组成空间，而这个空间在很大程度上仍未被探索。该项目将第一原理量子力学计算与材料信息学相结合，以快速预测有前途的新半导体。先进的合成和表征技术被用来优化这些半导体的微结构和提高其性能。该项目的教育和推广部分侧重于使研究生和本科生为实现先进能源技术所需的劳动力做好准备。该项目利用一个共同建议的博士项目--麦克唐纳学院全球能源与环境伙伴关系(MAGEEP)，为研究生提供国际经验，让他们与发展中国家大学的同行进行互动，在发展中国家，能源问题起着至关重要的作用。技术细节：该项目寻求发现高性能和容错半导体，可以在各种应用中取代不稳定和有毒的卤化铅钙钛矿，包括在高效太阳能电池和光催化中。这是通过用3+氧化态的等电子铋离子取代2+氧化态的有毒铅阳离子来实现的，而不会损害钙钛矿骨架的优点。这项交叉学科的研究将第一性原理密度泛函理论计算与材料信息学相结合，加速了具有靶向带隙和电子结构的稳定的Bi基钙钛矿的发现。这项研究结合了固相化学、湿化学和基于气溶胶的合成技术来合成预测材料并控制其微观结构。它使用多种表征技术，包括像差校正扫描、透射式电子显微镜成像和单色电子能量损失谱，用于对合成材料中的缺陷进行原子尺度的表征。教育方面包括对本科生和研究生的培训，包括接触从事能源材料工作的国际学生，以及为圣路易斯和周边地区学校的K-12教师和学生组织关于纳米材料用于能源应用的夏季研讨会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL DESCRIPTION: The development of high-performance oxide semiconductors with desired electronic structure has direct implications on many energy-related applications including photovoltaics, high-power electronics, and photocatalysis. This project employs an integrated theoretical and experimental approach to rapidly discover new high-performance semiconductors based on perovskite-framework oxides and oxynitrides containing bismuth. This family of promising compounds represents a vast composition space that remains largely unexplored. The project combines first-principles quantum-mechanical calculations with materials informatics to rapidly predict promising new semiconductors. Advanced synthesis and characterization techniques are used to optimize the microstructure and improve the performance of these semiconductors. Education and outreach components of the project focus on preparing both graduate and undergraduate students for the workforce needed to realize advanced energy technologies. The project leverages a co-advised doctoral program, the McDonnell Academy Global Energy and Environmental Partnership (MAGEEP), to provide graduate students with an international experience to interact with their counterparts from universities in developing countries, where energy issues play a vital role. TECHNICAL DETAILS: The project seeks to discover high-performance and defect-tolerant semiconductors that can replace unstable and toxic lead-halide perovskites in a variety of applications including in high-efficiency solar cells and photocatalysis. This is carried out by replacing the toxic lead cation in 2+ oxidation state with isoelectronic bismuth cation in 3+ oxidation state, without compromising the advantages presented by the perovskite framework. This interdisciplinary research combines first-principles density-functional theory calculations with materials informatics to accelerate the discovery of stable Bi-based perovskites with targeted band gap and electronic structure. The research employs a combination of solid-state chemistry, wet-chemistry and aerosol-based synthesis techniques to synthesize the predicted materials and control their microstructure. It uses a variety of characterization techniques including aberration-corrected scanning transmission electron microscope imaging and monochromated electron energy loss spectroscopy for atomic-scale characterization of the defects in the synthesized materials. Education aspects include training of undergraduate and graduate students including exposure to international students working on energy materials and the organization of summer workshops on nanomaterials for energy applications for K-12 teachers and students from schools in St. Louis and the surrounding region.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.