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.

智力优异的钙钛矿氧化物是由含量的无毒元素制成的，可以在高质量的异质结构中合成，并且具有可以通过掺杂的电子特性。尽管这些特性使它们成为太阳能转化的有前途的候选人，但基本的科学见解，例如了解限制光激发载体的重组寿命的机制，在可以利用复杂的氧化物以进行有效的太阳能转换之前。该项目的智力使命是确定使用高级薄膜沉积和超快光谱法的组合，以最大程度地激发光激发载体寿命和移动性。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），使用氧化物分子束相互酱进行合成。温度依赖的时间分辨出Terahertz光谱（TRT），UV/可见的瞬态吸收（TA）光谱和霍尔效应测量值将用于孔隙蛋白酶薄膜中光激发载体和迁移率的动态。通过对钙钛矿光体物理学的详细研究，这项工作将为新一代的基于氧化物的太阳能转化设备奠定科学基础。更广泛的影响力这将为设计和选择新的钙钛矿氧化物具有长寿命，高载流子迁移率和最佳带隙以实现太阳能转换的最佳基础。有效，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。该项目将通过活动推进科学教育，包括培训研究生和本科生在材料合成和特征技术方面，学生参与科学会议以及薄膜沉积和超级临时光谱设备的课堂演示。外展活动还将扩展到PIS的大学前学生吗？通过NSF RET和大学发起的计划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，他们的学生团体超过80％。