Mechanisms for enhancing n-type polaronic transport in transition metal oxides: ionic size, pair formation/clustering, and valence effects

增强过渡金属氧化物中 n 型极化子输运的机制：离子大小、成对形成/成簇和价态效应

• 批准号: 2003563
• 负责人: Yat Li
• 金额: $ 53.22万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003563&HistoricalAwards=false
• 关键词: Mechanisms; enhancing; type; polaronic; transport

Non-Technical Abstract This award supports a project focused on studying a group of materials called transition metal oxides. These materials are promising candidates for making devices for storing energy such as lithium-ion batteries and for converting energy such as solar cells. However, their efficiency has been fundamentally limited by the slow movement of negative and positive charges in them, restricting their use in practical applications. The main reason for the restricted movement of these charges is that they get trapped by the distortions in the materials’ atomic structure. This project will investigate the use of dopants to improve the mobility of the charges in iron oxide, a representative of these transition metal oxides. It will determine the design principles of “good” dopants that improve the transport of charges in these oxides so that they can be used in practical energy applications. The project will train undergraduate and graduate students and will engage in outreach activities involving high school students, emphasizing in broadening participation of underrepresented students.Technical Abstract This research project aims to quantitatively investigate the mechanisms that limit charge transport, including how the clustering of extrinsic n-type dopants takes place, how the interaction between electron small polarons and (clustered) dopants affects the electronic transport properties, and what steps might increase the carrier concentration in transition metal oxides. This project will initially use hematite, a representative polaronic oxide, doped with tin and other 4+/5+ ions as a model system for the study. The dopant clustering is believed to be due to ionic size mismatch, and consequently limit the carrier conductivity. The research team will use a “co-doping” strategy to improve the solubility of dopants and avoid clustering and correspondingly enhance carrier mobility as a function of doping concentration. A crucial step in this project is determining the local environment about extrinsic dopants and dopant clusters and if/how they are modified when the second dopants are incorporated; this work will combine physical measurements with first-principles simulations. The findings in this project can provide rules for rational design of polaronic oxides with improved transport properties, and more importantly, develop a fundamental understanding of key factors determining whether an isolated dopant, dopant cluster or co-doping can be beneficial or harmful for transport properties.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.

非技术摘要该奖项支持一个旨在研究一组称为过渡金属氧化物的材料的项目。这些材料是候选者，用于制作存储能量（例如锂离子电池）和转换能量（例如太阳能电池）的设备。但是，它们的效率从根本上受到了负电荷的缓慢运动的限制，从而限制了它们在实际应用中的使用。这些指控受到限制运动的主要原因是它们被材料原子结构中的扭曲所困扰。该项目将研究使用掺杂剂来改善电荷在氧化铁中的迁移率，这是这些过渡金属氧化物的代表。它将确定“良好”掺杂剂的设计原理，以改善这些氧化物中电荷的运输，从而可以在实用的能源应用中使用。该项目将培训本科和研究生，并将从事涉及高中生的外展活动，强调扩大代表性不足的学生的参与。技术摘要该研究项目旨在定量地研究限制电荷运输的机制，包括质量N型座位的群集，包括如何在属性中进行交通，以及如何在电源中进行电子交通，并在构图之间增加了电源型和（属性）（在极地）之间（clistect and toctions dop）（（过渡金属氧化物中的载体浓度。该项目研究团队将采用“共同兴奋剂”策略来改善掺杂剂的溶解度，并避免聚类并相应地增强载流子移动性，这是兴奋剂浓度的函数。该项目的关键步骤是确定有关外掺杂剂和掺杂群簇的本地环境，以及当第二个掺杂剂合并时如何修改它们；这项工作将将物理测量与第一原理模拟相结合。该项目中的发现可以为具有改进的运输特性的二极管氧化物的合理设计提供规则，并且更重要的是，对决定一个孤立的毒剂，毒剂集群或共同兴奋剂是有益或有害的关键因素可以对运输属性有益或有害。该奖项对NSF的法规及其进行了评估的构成构成的影响，这是诚实地反映出的构成者的构成师的构成师的范围。

项目成果

Doping Bottleneck in Hematite: Multipole Clustering by Small Polarons

• DOI: 10.1021/acs.chemmater.1c00304
• 发表时间: 2021-06
• 期刊: Chemistry of Materials
• 影响因子: 8.6
• 作者: T. Smart;Valentin Urena Baltazar;Mingpeng Chen;Bin Yao;Kiley Mayford;F. Bridges;Yat Li;Y. Ping-Y.-P

Insights on Thickness-Dependent Charge Transfer Efficiency Modulated by Ultrasonic Treatment in Hematite Photoanodes

• DOI: 10.1021/acs.jpcc.0c11397
• 发表时间: 2021-04-29
• 期刊: JOURNAL OF PHYSICAL CHEMISTRY C
• 影响因子: 3.7
• 作者: Freitas, Andre L. M.;Tofanello, Aryane;Li, Yat
• 通讯作者: Li, Yat

The critical role of synthesis conditions on small polaron carrier concentrations in hematite—A first-principles study

• DOI: 10.1063/5.0074698
• 发表时间: 2021-12
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: T. Smart;Mingpeng Chen;Andrew C. Grieder;Valentin Urena Baltazar;F. Bridges;Yat Li;Y. Ping

The impacts of dopants on the small polaron mobility and conductivity in hematite – the role of disorder

掺杂剂对赤铁矿中小极化子迁移率和电导率的影响——无序的作用

• DOI: 10.1039/d2nr04807h
• 发表时间: 2023
• 期刊: Nanoscale
• 影响因子: 6.7
• 作者: Chen, Mingpeng;Grieder, Andrew C.;Smart, Tyler J.;Mayford, Kiley;McNair, Samuel;Pinongcos, Anica;Eisenberg, Samuel;Bridges, Frank;Li, Yat;Ping, Yuan
• 通讯作者: Ping, Yuan