Excellence in Research: 3D Printed Radiation Detectors with Perovskite-Polymer Composites

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Current radiation detectors for nuclear material determination use inorganic single crystals that are processed at high temperatures and difficult to scale up to large sizes. A large detector size is essential for obtaining high accuracy and efficiency for detecting nuclear materials of interest including highly enriched uranium and plutonium-239 especially in a moving cargo. Large area and low-cost radiation detectors will also enhance operation efficiency and improve quality control of many industrial mining and metallurgical processes. In addition, pixelated radiation detector arrays are required for nuclear medical diagnostics and for the study of particle physics in outer space. Current detector arrays with inorganic single crystals have suffered from a limited spatial resolution due to the difficulties of machining these single crystals into small size pixels and assembling them into dense detector arrays. To solve these challenges, the team aims to develop new semiconductor-polymer composites as a replacement of the conventional single crystals for radiation detectors and detector arrays. If successful, there will be tremendous processing and manufacturing advantages of the composites compared with their inorganic single crystal counterparts, for instance, the composites can be potentially processed like commodity plastics by solution casting, hot pressing, melt extrusion and injection molding to achieve radiation detectors with large sizes and various shapes, or by 3D printing to achieve detector arrays with an unprecedented high spatial resolution and manufacturing flexibility.Technical summary:The project will investigate a group of organometal halide perovskite (perovskite) semiconductors and their polymer matrix composites. The state-of-the-art perovskite semiconductors exhibit a long charge carrier lifetime and high carrier mobility, contain high atomic number elements (cesium, lead, and iodine), and have a high radiation hardness, making them ideal candidates for radiation detector application. Moreover, they can be readily dissolved in many organic solvents, facilitating the formulation of perovskite-polymer composites for this proposed project. The work will lead to fundamental understanding of the structure, processing, and property relationships of halide perovskite-polymer composites including, 1) how to engineer the chemical interfaces between the perovskite and polymer phases to improve perovskite crystal dispersity and suppress ionic charge migration; and 2) how to engineer the electronic interfaces in the composite to enhance and balance both electron and hole collection upon irradiation of high energy photons. If successful, the work will establish a new era of additive manufacturing by investigating for the first time the 3D printing of perovskite-polymer composites for high-resolution pixelated radiation detectors. The knowledge of understanding and engineering charge transport processes in the composites can provide importance guidance for future exploration of other semiconductor-polymer composites for new generation large scale, low-cost optoelectronic manufacturing. This project will also help create a new educational program at a historically black public university (Florida Agricultural and Mechanical University) for the training of underrepresented engineering students to fuel the workforce pipeline in manufacturing, electronics, semiconductors, and national security industries.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.