Colloidal semiconductor nanocrystal quantum dots (QDs) have been extensively studied for applications in optoelectronic devices, biosensing, and imaging. Recent interest has turned to heavy metal-free compositions such as indium phosphide as an alternative to cadmium- and lead-based materials. Photoluminescence emission from InP QDs is size-tunable over a wide spectral range, providing superior color tuning compared to traditional CdSe QD but their optical properties and chemical synthesis is less well established. This study examines how InP-based heterostructures can be engineered to enhance their utility as heavy metal-free fluorophores emitting throughout the visible and near infrared (NIR) wavelength ranges by addressing three fundamental materials design and synthesis issues.
First, the bandgap engineering of InP-based QDs is achieved by varying the core size, shell composition, and shell thickness of a core/shell heterostructures, generating emitters spanning 500 – 1100 nm. Second, the brightness mismatch between small blue/green emitters and large red-emitting QDs is addressed by tuning the absorption cross-section and extinction coefficient by synthesizing a series of QDs with a combination of core sizes, shell thicknesses, and shell compositions, resulting in a rainbow of brightness-matched InP emitters. Finally, the synthesis of inverted InP heterostructures, producing the reddest-emitting InP QDs ever reported by generating photoluminescence from a quantum confined InP shell, was significantly improved. The non-toxic nature of InP in conjunction with its unique optical properties render it an excellent candidate for use in in vitro and in vivo clinical or commercial settings.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/41994 |
| Date | 05 February 2021 |
| Creators | Toufanian, Reyhaneh |
| Contributors | Dennis, Allison M. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution-NonCommercial 4.0 International, http://creativecommons.org/licenses/by-nc/4.0/ |
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