Excellence in Research: Lanthanide doped nanoparticles for sensitive photodetectors of short-wave radiation

非技术性紧凑、坚固、灵敏的短波长辐射（紫外线和X射线）探测器对于推进各种应用至关重要，包括成像、监测大气气体、医疗应用和国土安全。现有的紫外线探测器使用真空光电倍增管，既不坚固也不耐用，而紧凑和坚固的光电二极管对紫外线和X射线视而不见。该研究项目通过专注于镧系元素掺杂的钙钛矿纳米颗粒来解决这一需求，这些纳米颗粒可以捕获紫外线和X射线光子，并将其转化为易于检测的可见光和近红外光子。镧系元素掺杂的钙钛矿纳米颗粒与硅雪崩光电探测器的组合有望作为灵敏的短波长光电探测器工作，能够以10纳秒内一个光子的速度感测几个光子。在科学领域吸引和留住女性和代表性不足的少数民族（URM）是团队通过各种互补努力解决的系统性挑战。该项目包括针对K-12学生和更广泛社区的大学预科外展计划，促进对所进行科学的曝光和兴奋。该项目旨在开发镧系元素掺杂的金属卤化物钙钛矿纳米晶体，能够作为高效的发光材料，将短波长（SWL）辐射下转换为可见光和近红外辐射，并通过紧凑和坚固的手段实现SWL辐射的灵敏检测。该项目的主要目标是调查的方法的可行性的基础上集成这种半导体与硅雪崩光电二极管（APD），并证明拟议的敏感SWL光电探测器的功能。技术目标是合成和表征掺杂镧系元素的钙钛矿纳米颗粒，将纳米复合膜集成到SWL光电探测器中。该项目将通过女性和代表性不足的少数民族大学生参与该项目，为她们提供指导和培训。由于钙钛矿纳米颗粒捕获UV和X射线光子的优异能力，并将其激子态的能量无辐射地转移到在可见光和NIR中重新发射的嵌入的Ln离子，因此将实现有效的下转换。由X射线引起的强闪烁将是由于铅和镧系离子的联合作用导致的X射线光子的短停止范围。开展拟议活动的计划包括从纳米粒子合成到与硅APD集成以及在暴露于紫外线和X射线源下测试SWL传感器的所有步骤。该计划的基本原理是基于文献中提出的方法和PI自己的研究。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NontechnicalCompact, rugged, and sensitive detectors of short wavelength radiation (ultraviolet and X-rays) are critical to advance a variety of applications, including imaging, monitoring atmospheric gases, medical applications, and and homeland security. Existing UV detectors use vacuum photomultiplier tubes, which are neither rugged nor durable, whereas compact and rugged photodiodes are blind to UV and X-rays. This research project addresses this need by focusing on lanthanide-doped perovskite nanoparticles that capture UV and X-ray photons and convert them into easily-detected visible and near infrared photons. The combination of lanthanide-doped perovskite nanoparticles with silicon avalanche photodetectors is expected to work as sensitive short-wavelength photodetectors capable of sensing a few photons with a speed as high as one photon in 10 nanoseconds. Engaging and retaining women and underrepresented minorities (URMs) in the sciences is a systemic challenge the team addresses through a variety of complementary efforts. The project encompasses pre-college outreach programs targeting K-12 students and the broader community, fostering exposure and excitement about the science conducted. Undergraduates will obtain research experience preparing them for graduate school through a set of initiatives, especially focusing on URM students.TechnicalThe project aims to develop lanthanide-doped metal halide perovskite nanocrystals capable of serving as efficient scintillators that down-convert short wavelength (SWL) radiation to visible and near-IR radiation and enable sensitive detection of SWL radiation by compact and rugged means. The primary goal of the project is to investigate the feasibility of the approach based on integrating such scintillators with silicon avalance photodiodes (APDs) and to demonstrate functioning of the proposed sensitive SWL photodetector. The technical objectives are to synthesize and characterize perovskite nanoparticles doped with lanthanides, integrate nanocomposite films into SWL photodetectors. The project will provide guidance and training for female and underrepresented minority undergraduate students through their participation in the project. Efficient down conversion will be acehived due to the excellent ability of perovskite nanoparticles to capture UV and X-ray photons, and transfer radiationlessly the energy of their exciton states to the embedded Ln ions that re-emit in visible and NIR. Strong scintillation induced by X-rays will be due to short stopping range of the X-ray photons resulting from combined action of lead and lanthanide ions. The plan for conducting the proposed activities includes all the steps from synthesis of the NPs to integration with silicon APDs and testing the SWL sensors under exposure to UV and X-ray sources. The plan rationale is based on the approaches presented in the literature and from the PI’s own research.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.