Compositional and Structural Dependence of Photosensitivity in Photoexcitable Storage Phosphors

About This Grant

Non-technical Summary: The ability to store information and retrieve it in a non-destructive fashion is critical in health care (radiation dosimetry), information science (quantum data storage), and defense (anticounterfeiting). Photosensitive nanomaterials are uniquely suited as optical storage media because they have the potential to simultaneously afford high storage density, fast and non-destructive readout, and low energy consumption. Yet, the library of nanomaterials for real-world applications remains limited, because no definitive principles to design materials with the desired photosensitive response exist. With support from the Solid State and Materials Chemistry Program and the Electronic and Photonic Materials Program, both in NSF’s Division of Materials Research, Prof. Rabuffetti and his research team at Wayne State University explore new photosensitive nanomaterials in this research project. They investigate rules governing photosensitivity at the nanoscale through a combination of chemical and spectroscopic studies and from there develop design principles. In addition, this research provides opportunities for workforce development at both undergraduate and graduate levels and K-12 STEM outreach. Graduate and undergraduate students are trained in the synthesis and advanced characterization of optical nanomaterials. 6th through 9th grade students participating in the annual STEM Day hosted by Wayne State University are introduced to optical materials research through a hands-on activity based on photosensitive materials. Technical Summary: With support from the Solid State and Materials Chemistry Program and the Electronic and Photonic Materials Program, both in NSF’s Division of Materials Research, researchers develop an understanding of how to control the photosensitivity of photoexcitable storage nanophosphors. This is done by exploiting various chemical and structural tunabilities of a novel family of host materials. Three specific research thrusts are pursued: a) Targeted synthesis of a series of nanophosphors that incorporate trivalent rare-earth dopants as photosensitive centers. To this end, colloidal synthetic routes to nanocrystals with uniform morphology and well-defined doping levels are developed. b) Establishing the spatial distribution of photoactive centers by probing the atomic structure of the nanophosphors. This task involves interrogating the atomic arrangement in multiple length scales using element-specific spectroscopic probes. c) Elucidating the role of the phosphor’s crystal-chemistry on photochemical and photophysical processes that underpin the photosensitive response. Metrics that quantitatively describe chemical composition, crystal structure, and photosensitivity are correlated, enabling the researchers to derive principles which enable control of photosensitive response via rational manipulation of phosphor composition, structure, and morphology. In addition to undergraduate and graduate student training, 6th through 9th grade students participating in the annual STEM Day hosted by Wayne State University are introduced to optical materials research through a hands-on activity based on photosensitive materials. 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.