Biofunctional Silicon Nanoparticles by Means of Thiol‐Ene Click Chemistry

Ruizendaal, L.; Pujari, Sidharam P.; Gevaerts, Veronique S.; Paulusse, Jos M. J.; Zuilhof, Han

doi:10.1002/asia.201100375

Cited by 74 publications

(96 citation statements)

References 99 publications

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“…2,3 More versatile surface engineering and customisable organic termination can be achieved by chemical synthesis, [8][9][10][11] which also could allow for macroscopic production yields of Si-QDs. 12 In this case, alkylchains are good candidates for surface passivation, stabilizing it, preventing photo-oxidation (owing to formation of a strong covalent Si-C bond), and averting aggregation in solution.…”

Section: Introductionmentioning

confidence: 99%

Surface brightens up Si quantum dots: direct bandgap-like size-tunable emission

et al. 2013

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Colloidal semiconductor quantum dots (QDs) constitute a perfect material for ink-jet printable large area displays, photovoltaics, light-emitting diode, bio-imaging luminescent markers and many other applications. For this purpose, efficient light emission/ absorption and spectral tunability are necessary conditions. These are currently fulfilled by the direct bandgap materials. Si-QDs could offer the solution to major hurdles posed by these materials, namely, toxicity (e.g., Cd-, Pb-or As-based QDs), scarcity (e.g., QD with In, Se, Te) and/or instability. Here we show that by combining quantum confinement with dedicated surface engineering, the biggest drawback of Si-the indirect bandgap nature-can be overcome, and a 'direct bandgap' variety of Si-QDs is created. We demonstrate this transformation on chemically synthesized Si-QDs using state-of-the-art optical spectroscopy and theoretical modelling. The carbon surface termination gives rise to drastic modification in electron and hole wavefunctions and radiative transitions between the lowest excited states of electron and hole attain 'direct bandgap-like' (phonon-less) character. This results in efficient fast emission, tunable within the visible spectral range by QD size. These findings are fully justified within a tight-binding theoretical model. When the C surface termination is replaced by oxygen, the emission is converted into the well-known red luminescence, with microsecond decay and limited spectral tunability. In that way, the 'direct bandgap' Si-QDs convert into the 'traditional' indirect bandgap form, thoroughly investigated in the past.

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Section: Introductionmentioning

confidence: 99%

Surface brightens up Si quantum dots: direct bandgap-like size-tunable emission

et al. 2013

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“…8 SiQDs with mean diameter (2.2 ± 0.5) nm, are butyl capped and deposited densely on quartz substrate by drop-casting. Exclusion of oxygen on the SiQD surface was assured by careful synthesis of SiQDs in argon atmosphere.…”

Section: Methodsmentioning

confidence: 99%

Thermally Activated Emission from Direct Bandgap-Like Silicon Quantum Dots

Dohnalová

Saeed

Poddubny

et al. 2013

ECS J. Solid State Sci. Technol.

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Thermally activated emission from direct bandgap-like silicon quantum dotsNewell, K.; Saeed, S.; Poddubny, A. N.; Prokofiev, A.A.; Gregorkiewicz, T. Published in: ECS J.Solid State Science Technology DOI:10.1149/2.004306jss Link to publicationCitation for published version (APA): Dohnalova, K., Saeed, S., Poddubny, A. N., Prokofiev, A. A., & Gregorkiewicz, T. (2013). Thermally activated emission from direct bandgap-like silicon quantum dots. ECS J.Solid State Science Technology, 2(6), R97-R99. DOI: 10.1149/2.004306jss General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. A. F. Ioffe Physical-Technical Institute RAS, 19402 Saint-Petersburg, Russia Due to the covalent character of silicon-carbon (Si-C) bond, C-linked molecules on the silicon quantum dot (SiQD) surface lead to dramatic changes in wavefunctions of the excited electron-hole pairs. Some of the optical transitions are strongly modified and attain direct bandgap-like character, giving rise to bright phonon-less fast decaying emission, while many other transitions keep their typical indirect bandgap character. It appears that in C-terminated SiQDs, with diameter larger than ∼2 nm, the most efficient recombination occurs from states slightly above the ground state. This leads to thermal activation of the fast emission, dominating the photoluminescence from these SiQDs. On the other hand, in the smallest SiQDs of less than 2 nm, the lowest excited states have the direct bandgap-like character and therefore their emission becomes gradually dominant at lower temperatures, as indeed supported by our experimental observations. Indirect band gap limits optical applications of bulk silicon and silicon nanostructures. Low radiative rate compared to fast nonradiative recombination rate leads to a very low internal quantum efficiency of emission. Therefore in silicon, emission efficiency is much more sensitive to the presence of nonradiative channels than for direct bandgap materials. In order to improve the optical faculty of Si many approaches have been explored, with the most prominent ones being optical doping, 1,2 nanostructuring 3 and a combination of the two. 4 In particular, SiQDs turn out to offer many opportunities, either in form of oxygen passivated SiQDs 5 or with customizable organic passivation, 6-17 ac...

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“…In the case of silicon quantum dots, detection of small molecule analytes have been achieved, such as TNT [135], dopamine [136], and certain metal ions [137], while measurement of macromolecular activities was seen only recently [138]. Cheng et al showed that attaching a short dye labelled peptide to silicon quantum dots, with thiol-ene 'click' chemistry allowed the generation of FRET between silicon quantum dots and the dye whose intensity is enzyme responsive [101,139,140]. By this way they were able to for the first time control the surface to allow measurement of protease activity using colloidal silicon quantum dots.…”

Section: Bio-applicationsmentioning

confidence: 99%

Optical Biosensing and Bioimaging With Porous Silicon and Silicon Quantum Dots (Invited Review)

Guan¹

2017

PIER

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Biofunctional Silicon Nanoparticles by Means of Thiol‐Ene Click Chemistry

Cited by 74 publications

References 99 publications

Surface brightens up Si quantum dots: direct bandgap-like size-tunable emission

Surface brightens up Si quantum dots: direct bandgap-like size-tunable emission

Thermally Activated Emission from Direct Bandgap-Like Silicon Quantum Dots

Optical Biosensing and Bioimaging With Porous Silicon and Silicon Quantum Dots (Invited Review)

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