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

Oakwood College, Huntsville AL

Investigators

Abstract

Nontechnical Compact, 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. Technical The 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.