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

非技术紧凑、坚固和灵敏的短波长辐射(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、医疗应用和国家安全。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射线是盲目的。这项研究项目通过专注于掺镧钙钛矿纳米颗粒来满足这一需求，该纳米颗粒可以捕获紫外线和X射线光子，并将它们转换为易于检测的可见光和近红外光子。将稀土掺杂的钙钛矿纳米粒子与硅雪崩光电探测器相结合，有望成为灵敏的短波长光电探测器，能够在10纳秒内以高达一个光子的速度探测到几个光子。在科学界吸引和留住妇女和代表性不足的少数群体(URM)是该小组通过各种补充努力应对的系统性挑战。该项目包括针对K-12学生和更广泛的社区的大学前外展计划，培养对所进行的科学的接触和兴奋。本科生将通过一系列举措获得研究经验，为他们进入研究生院做准备，特别是针对URM学生。该项目旨在开发能够作为高效闪烁体的稀土掺杂金属卤化物钙钛矿纳米晶体，将短波(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方法实现对SWL辐射的灵敏检测。该项目的主要目标是研究将这种闪烁体与硅平均光电二极管(APD)集成的方法的可行性，并演示拟议的灵敏SWL光电探测器的功能。其技术目标是合成和表征掺杂稀土的钙钛矿纳米粒子，将纳米复合薄膜集成到SWL光电探测器中。该项目将通过参与该项目为女性和代表性不足的少数族裔本科生提供指导和培训。由于钙钛矿型纳米粒子能够捕获紫外线和X射线光子，并将其激子态的能量无辐射地转移到嵌入的Ln离子中，在可见光和近红外中重新发射，因此有效的下转换将被避免。X射线的强闪烁是由于铅和稀土离子共同作用导致的X射线光子的短阻止距离所致。实施拟议活动的计划包括从合成NPs到与硅APD集成以及在紫外线和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。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.