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Allison Dennis1

1, Boston University, Boston, Massachusetts, United States

The future of semiconductor quantum dots (QDs) in biomedical imaging lies not with well-established CdSe-based materials that raise issues of toxicity and limited tissue penetration depths, but rather with heavy metal-free compositions that emit in the near infrared (NIR) and short wave infrared (SWIR) in addition to visible wavelength ranges. With this motivation, we have developed semiconductor quantum shells (QSs) comprising non-toxic constituents. These ZnSe/InP/ZnS core/shell/shell structures are dubbed QSs because their Inverted-Type I bandgap structure yields quantum confinement-based emission from the InP shell. The excitonic emission from the QSs is tunable from the visible through the NIR with shell thickness, yielding emission peaks ranging from 515 – 850 nm. This tunablility range is wider than that seen for Type I InP QDs, particularly expanding emission deeper in the first optical tissue window, which spans from 650 – 950 nm. In this talk, I will detail the synthetic control of these heterostructured nanomaterials. In depth photophysical characterization has elucidated the structure/function relationship, enabling the concerted design of these emitters. Of particular note is our ability to match the brightness of emitters of various colors by tuning both the core size and shell thickness. The presentation will include early nanotoxicity and animal imaging results.

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