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Photoexcited Carrier Dynamics in Oxide Semiconductors for Photovoltaics

光伏氧化物半导体中的光激发载流子动力学

基本信息

批准号：
1201957
负责人：
Steven May
金额：
$ 38万
依托单位：
Drexel University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2016-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1201957&HistoricalAwards=false
关键词：
Photoexcited Carrier Dynamics Oxide Semiconductors

项目摘要

Intellectual MeritSemiconducting perovskite oxides are made from earth-abundant, non-toxic elements, can be synthesized in high quality heterostructures, and have electronic properties that can be tuned through doping. While these properties make them promising candidates for solar energy conversion, fundamental scientific insights, such as understanding the mechanisms that limit recombination lifetime of photoexcited carriers, are necessary before complex oxides can be utilized for efficient solar energy conversion. The intellectual mission of this project is to identify strategies to maximize photoexcited carrier lifetime and mobility using a combination of advanced thin film deposition and ultrafast spectroscopy. Thin film heterostructures consisting of the ABO3 perovskite structure, where A is a rare earth or alkaline earth ion and B is a transition metal ion (A = Sr, La, Eu; B = Cr, Fe), will be synthesized using oxide molecular beam epitaxy. Temperature-dependent time resolved terahertz spectroscopy (TRTS), UV/visible transient absorption (TA) spectroscopies, and Hall effect measurements will be used to probe dynamics of photoexcited carriers and mobility in the perovskite thin films. Through this detailed study of perovskite photophysics, this work will lay the scientific foundation for a new generation of oxide-based solar energy conversion devices. Broader ImpactThis project will provide a rational basis for designing and selecting new perovskite oxides with long lifetimes, high carrier mobilities, and optimal band gaps for solar energy conversion. Availability of efficient, low-cost, clean, and sustainable photovoltaics and photocatalysts made from earth-abundant, non-toxic materials would have transformative impact on the US energy portfolio. The project will advance scientific education through activities including the training of graduate and undergraduate students in materials synthesis and characterization techniques, student participation in scientific conferences, and in-class demonstrations of thin film deposition and ultrafast spectroscopy equipment. Outreach will also extend to pre-college students by the PIs? continued participation in mentoring local high school teachers through NSF RET and university-initiated programs. These programs are particularly beneficial for underrepresented groups since most teachers are from the School District of Philadelphia, whose student body is over 80% minorities.

智力优点半导体钙钛矿氧化物由地球上储量丰富的无毒元素制成，可以合成高质量的异质结构，并且具有可以通过掺杂调节的电子特性。虽然这些特性使它们成为太阳能转换的有希望的候选者，但在将复杂氧化物用于高效太阳能转换之前，必须了解基本的科学见解，例如了解限制光激发载流子复合寿命的机制。该项目的智力任务是确定利用先进薄膜沉积和超快光谱相结合来最大化光激发载流子寿命和迁移率的策略。由 ABO3 钙钛矿结构组成的薄膜异质结构，其中 A 是稀土或碱土离子，B 是过渡金属离子（A = Sr、La、Eu；B = Cr、Fe），将使用氧化物分子束外延合成。温度依赖性时间分辨太赫兹光谱（TRTS）、紫外/可见瞬态吸收（TA）光谱和霍尔效应测量将用于探测钙钛矿薄膜中光激发载流子的动力学和迁移率。通过对钙钛矿光物理的详细研究，这项工作将为新一代氧化物基太阳能转换器件奠定科学基础。更广泛的影响该项目将为设计和选择具有长寿命、高载流子迁移率和太阳能转换最佳带隙的新型钙钛矿氧化物提供合理的基础。由地球上丰富的无毒材料制成的高效、低成本、清洁和可持续的光伏和光催化剂的可用性将对美国的能源组合产生变革性的影响。该项目将通过对研究生和本科生进行材料合成和表征技术培训、学生参加科学会议以及薄膜沉积和超快光谱设备课堂演示等活动来推进科学教育。 PI 也会将外展活动延伸至大学预科学生吗？通过 NSF RET 和大学发起的项目继续参与指导当地高中教师。这些计划对代表性不足的群体特别有益，因为大多数教师来自费城学区，该学区的学生中超过 80% 是少数族裔。