Abstract:Silicon Quantum Dots (SQDs) have recently attracted great interest due to their excellent optical properties, low cytotoxicity, and ease of surface modification. The size of SQDs and type of ligand on their surface has a great influence on their optical properties which is still poorly understood. Here we report the synthesis and spectroscopic studies of three families of unreported SQDs functionalized by covalently linking to the aromatic fluorophores, 9-vinylphenanthrene, 1-vinylpyrene, and 3-vinylperylene. … Show more
“…With the incorporation of PSs such as naphthalene, fluorene, phenanthrene, or pyrene, the conversion is increased first and then decreased with more PS, but it is decreased with the introduction of biphenyl, anthracene, and perylene. It has proven that the linear arrangement of conjugated dense rings like naphthalene and anthracene is beneficial to the flow of π electrons, thus reducing the absorption energy needed to transit reaction system . Additionally, such polynuclear aromatic compounds suffer from several serious drawbacks that limit their utility as practical PSs.…”
Section: Resultsmentioning
confidence: 99%
“…By comparison, it can infer that the quantum yield of (Me‐Cp)PtMe 3 is increased by 24.8% after the incorporation of naphthalene. It means that (Me‐Cp)PtMe 3 is sensitized by the PS naphthalene via the efficient energy transfer from PS to photocatalyst, which can enhance the quantum efficiency of photochemical reactions …”
Hydrosilylation is commonly known as a thermally induced addition reaction between unsaturated bonds and Si H bonds to synthesize or crosslink organosilanes and organosilicones, while it has emerged that it can also be activated under the coaction of UV irradiation and specific platinum catalyst. For higher photopolymerization conversion, excessive platinum catalyst is always required; however, this inevitably causes the significant increase of production cost and decrease of operation time. In this study, traces of trimethyl(methylcyclopentadienyl) platinum (IV) (Me-Cp)Pt(Me) 3 catalysts is combined with different photosensitizers (PSs) to efficiently promote the UV-activated hydrosilylation. Naphthalene is found to be the most applicable PS, because it improves the photopolymerization conversion from about 70 to 100% for the crosslinking of silicone rubbers. This UV-activated hydrosilylation is more likely to follow the first-order reaction kinetics, and its activation energy is 30.9 kJ mol −1 . The mechanical properties and thermostability of UV-crosslinked silicone rubbers are also enhanced with the incorporation of naphthalene. Moreover, this UV-activated hydrosilylation of silicone rubbers reveals a potential role to prepare complicated geometry shapes by photolithography.
“…With the incorporation of PSs such as naphthalene, fluorene, phenanthrene, or pyrene, the conversion is increased first and then decreased with more PS, but it is decreased with the introduction of biphenyl, anthracene, and perylene. It has proven that the linear arrangement of conjugated dense rings like naphthalene and anthracene is beneficial to the flow of π electrons, thus reducing the absorption energy needed to transit reaction system . Additionally, such polynuclear aromatic compounds suffer from several serious drawbacks that limit their utility as practical PSs.…”
Section: Resultsmentioning
confidence: 99%
“…By comparison, it can infer that the quantum yield of (Me‐Cp)PtMe 3 is increased by 24.8% after the incorporation of naphthalene. It means that (Me‐Cp)PtMe 3 is sensitized by the PS naphthalene via the efficient energy transfer from PS to photocatalyst, which can enhance the quantum efficiency of photochemical reactions …”
Hydrosilylation is commonly known as a thermally induced addition reaction between unsaturated bonds and Si H bonds to synthesize or crosslink organosilanes and organosilicones, while it has emerged that it can also be activated under the coaction of UV irradiation and specific platinum catalyst. For higher photopolymerization conversion, excessive platinum catalyst is always required; however, this inevitably causes the significant increase of production cost and decrease of operation time. In this study, traces of trimethyl(methylcyclopentadienyl) platinum (IV) (Me-Cp)Pt(Me) 3 catalysts is combined with different photosensitizers (PSs) to efficiently promote the UV-activated hydrosilylation. Naphthalene is found to be the most applicable PS, because it improves the photopolymerization conversion from about 70 to 100% for the crosslinking of silicone rubbers. This UV-activated hydrosilylation is more likely to follow the first-order reaction kinetics, and its activation energy is 30.9 kJ mol −1 . The mechanical properties and thermostability of UV-crosslinked silicone rubbers are also enhanced with the incorporation of naphthalene. Moreover, this UV-activated hydrosilylation of silicone rubbers reveals a potential role to prepare complicated geometry shapes by photolithography.
“…This is in agreement with the (111) plane of diamond structured silicon 23 . It should be noted that the low resolution of the TEM and HR-TEM images is assigned to the ultra-small dimensions of these SQDs and the small atomic weight of the silicon atom compared to the counterpart metallic or semiconductor quantum dots, which is known to provide low-quality visualization 10 , 24 . Figure 2 TEM together with HR-TEM (left) and diameter distribution with photographs for solutions under UV (365 nm) irradiation (right) for Am-SQD-Per ( A ) and Urea-SQD-Per ( B ).…”
Section: Resultsmentioning
confidence: 99%
“…The surface functionalization would then play a crucial role towards controlling the optical properties of SQDs 9 . It has been shown in previous studies that surface functionalization of SQDs with aromatic ligands helps tune their optical properties including their quantum yield and PL 10 , 11 . This strategy potentially can be utilized as a means to control the optical properties of SQDs.…”
Section: Introductionmentioning
confidence: 99%
“…Only a few reports in literature investigated the influence of aromatic fluorophores covalently linked to SQDs and the role of the spacer connecting the fluorophore on the optical properties of SQDs. Interestingly, the utilization of aromatic fluorophores as a capping agent was found to play a key role to control the optical properties of SQDs 10 , 13 – 16 .…”
The superior optical properties of Silicon Quantum Dots (SQDs) have made them of increasing interest for a variety of biological and opto-electronic applications. The surface functionalization of the SQDs with aromatic ligands plays a key role in controlling their optical properties due to the interaction of the ligands with the electronic wave function of SQDs. However, there is limited reports in literature describing the impact of spacer groups connecting the aromatic chromophore to SQDs on the optical properties of the SQDs. Herein, we report the synthesis of two SQDs assemblies (1.6 nm average diameter) functionalized with perylene-3,4,9,10-tetracarboxylic acid diimide (PDI) chromophore through N-propylurea and propylamine spacers. Depending on the nature of the spacer, the photophysical measurements provide clear evidence for efficient energy and/or electron transfer between the SQDs and PDI. Energy transfer was confirmed to be the operative process when propylurea spacer was used, in which the rate was estimated to be ~2 × 109 s−1. On the other hand, the propylamine spacer was found to facilitate electron transfer process within the SQDs assembly. To illustrate functionality, the water soluble SQD-N-propylurea-PDI assembly was proven to be nontoxic and efficient for fluorescent imaging of embryonic kidney HEK293 cells and human bone cancerous U2OS cells.
Luminescent solar concentrators (LSCs) have attracted significant attention as promising solar energy conversion devices for building integrated photovoltaic (PV) systems due to their simple architecture and cost‐effective fabrication. Conventional LSCs are generally comprised of an optical waveguide slab with embedded emissive species and coupled PV cells. Colloidal semiconductor quantum dots (QDs) have been demonstrated as efficient emissive species for high‐performance LSCs because of their outstanding optical properties including tunable absorption and emission spectra covering the ultraviolet/visible to near‐infrared region, high photoluminescence quantum yield, large absorption cross sections, and considerable photostability. However, current commonly used QDs for high‐performance LSCs consist of highly toxic heavy metals (i.e., cadmium and lead), which are fatal to human health and the environment. In this regard, it is highly desired that heavy metal‐free and environmentally friendly QD‐based LSCs are comprehensively studied. Here, notable advances and developments of LSCs based on unary, binary, and ternary eco‐friendly QDs are presented. The synthetic approaches, optical properties of these eco‐friendly QDs, and consequent device performance of QD‐based LSCs are discussed in detail. A brief outlook pointing out the existing challenges and prospective developments of eco‐friendly QD‐based LSCs is provided, offering guidelines for future device optimizations and commercialization.
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