Gas-phase grafting for the multifunctional surface modification of silicon quantum dots

Photon upconversion in systems incorporating inorganic quantum dots (QDs) is of great interest for applications in solar energy conversion, bioimaging, and photodynamic therapy. Achieving high up-conversion efficiency requires not only high-quality inorganic nanoparticles, but also precise control o...

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Bibliographic Details
Published in:Nanoscale 2022-12, Vol.14 (46), p.17385-17391
Main Authors: Schwan, Joseph, Wang, Kefu, Tang, Ming Lee, Mangolini, Lorenzo
Format: Article
Language:English
Subjects:
Chains
Functional groups
Grafting
Hydrosilylation
Low temperature
Medical imaging
Nanoparticles
Photodynamic therapy
Quantum dots
Silicon
Solar energy conversion
Upconversion
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Summary:Photon upconversion in systems incorporating inorganic quantum dots (QDs) is of great interest for applications in solar energy conversion, bioimaging, and photodynamic therapy. Achieving high up-conversion efficiency requires not only high-quality inorganic nanoparticles, but also precise control of their surface functional groups. Gas-phase surface functionalization provides a new pathway towards controlling the surface of small inorganic nanoparticles. In this contribution, we utilize a one-step low-temperature plasma technique for the synthesis and in-flight partial functionalization of silicon QDs with alkyl chains. The partially functionalized surface is then modified further with 9-vinylanthracene via thermal hydrosilylation resulting in the grafting of 9-ethylanthracene (9EA) groups. We have found that the minimum alkyl ligand density necessary for quantum dot solubility also gives the maximum upconversion quantum yield, reaching 17% for silicon QDs with Si-dodecyl chains and an average of 3 9EA molecules per particle. Gas-phase modification of silicon quantum dots enables a precise control of their surface functional groups, in turn enabling high photon upconversion efficiency.
ISSN:2040-3364
2040-3372
DOI:10.1039/d2nr04902c