LEAPS-MPS: Time- and depth-resolved charge carrier transport in phase stable hybrid perovskites

LEAPS-MPS：相稳定杂化钙钛矿中的时间和深度分辨载流子传输

• 批准号: 2316827
• 负责人: Meng-Ju Sher
• 金额: $ 23.83万
• 依托单位: Wesleyan University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2316827&HistoricalAwards=false
• 关键词: LEAPS; MPS; Time; depth; resolved

NON-TECHNICAL SUMMARYMixed halide perovskites are a novel class of hybrid semiconductors with organic and inorganic components. They have shown great promise for use in solar cells and light-emitting diodes, in part due to their highly tunable electronic and optical properties. However, fundamental limitations have limited their use. In particular, stability issues due to ion migration and phase segregation must be resolved. Complicating studies of pervoskites is the dynamic time scale of electronic processes. These span from picosecond electron scattering, nanosecond energy relaxation, to millisecond ionic motion. This LEAPS-MPS project will use terahertz waves that are sensitive to electron conduction to find pathways to develop stable hybrid perovskites. To achieve this goal, the PI will develop new non-contact terahertz characterization techniques to increase the probing window from picosecond to millisecond time scales. THz studies will be complemented by photoluminescence and X-ray characterization to investigate the dynamic coupling among electronic, optical, and structural properties. The PI emphasizes training for next generation scientists, involving undergraduate and graduate student researchers will be involved in the project. In addition, the PI leads the Girls in Science Camp for elementary school girls, with a team of female faculty members, high school, and college teaching assistants. Through intergenerational mentoring, this project contributes to the training of next-generation scientists and educators.TECHNICAL SUMMARYRecent developments in organic-inorganic hybrid perovskites have opened a wide range of opportunities for highly tunable materials. However, thermodynamically driven halide segregation in mixed-halide perovskites changes their optical and optoelectronic properties. Ionic motion also impacts material properties occurring in a solid, requiring a broad range of time scales to understand dynamic material properties. This LEAPS-MPS project seeks to develop depth- and time-resolved, non-contact characterization techniques to study the impact on charge carrier transport by the movement of halide ions upon light soaking and to find pathways to develop phase-stable hybrid perovskites. To achieve this goal, the PI will develop new optical pump, terahertz probe techniques using a ns-pulsed pump laser with electronic timing to extend the measurement time-window from 2 ns to beyond 1 ms to match carrier recombination dynamics and increase the dynamic probing window. THz studies will be complemented by time- and spatially-resolved photoluminescence and in situ X-ray scattering mapping to provide correlations with the local film stress and composition. Ultimately, this project will link picosecond carrier scattering, nanosecond recombination, and millisecond ionic motion to provide a comprehensive understanding of photocarrier dynamics.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.

非技术总结卤化物钙钛矿是具有有机和无机成分的新型混合半导体。他们显示出在太阳能电池和发光二极管中使用的巨大前景，部分原因是它们高度可调的电子和光学特性。但是，基本的限制限制了它们的使用。特别是，必须解决由于离子迁移和相分离引起的稳定性问题。泛素晶体的研究复杂化是电子过程的动态时间尺度。这些跨度从皮秒电子散射，纳米秒能量松弛到毫秒的离子运动。该飞跃-MPS项目将使用对电子传导敏感的Terahertz波来寻找发展稳定的混合钙晶的途径。为了实现这一目标，PI将开发新的非接触式Terahertz表征技术，以增加从picsecond到毫秒到毫秒的探测窗口。 THZ研究将通过光致发光和X射线表征进行补充，以研究电子，光学和结构特性之间的动态耦合。 PI强调了对下一代科学家的培训，涉及本科生和研究生研究人员将参与该项目。此外，PI还带领小学女生的科学训练营，由一支女教师，高中和大学教学助手组成。通过代际指导，该项目有助于培训下一代科学家和教育工作者。有机无机混合植物的技术摘要发展为高度可调材料开辟了很多机会。然而，混合壁钙化物中热力学驱动的卤化物分离改变了其光学和光电特性。离子运动还影响在固体中发生的材料特性，需要广泛的时间尺度才能了解动态材料特性。该跨越MPS项目旨在开发深度和时间分辨的非接触式特征技术，以研究卤化物离子对光浸泡的运动对电荷载体传输的影响，并找到开发相稳定的混合钙钛矿的途径。为了实现这一目标，PI将使用具有电子时机的NS脉冲泵激光器开发新的光泵，Terahertz探测技术，以将测量时间窗口从2 ns扩展到1 ms以上，以匹配载波重组动态并增加动态探测窗口。 THZ研究将由时间和空间分辨的光致发光以及原位X射线散射映射互补，以提供与局部膜应力和组成的相关性。最终，该项目将将皮秒载体散射，纳秒重组和毫秒的离子运动联系起来，以提供对光载体动力学的全面了解。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来通过评估来获得支持的。