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A large-scale synthetic strategy is developed for facile one-pot aqueous synthesis of silicon nanoparticles (SiNPs) yielding ∼0.1 g SiNPs of small sizes (∼2.2 nm) in 10 min. The as-prepared SiNPs feature strong fluorescence (photoluminescence quantum yield of 20-25%), favorable biocompatibility, and robust photo- and pH-stability. Moreover, the SiNPs are naturally water dispersible, requiring no additional post-treatment. Such SiNPs can serve as highly photostable bioprobes and are superbly suitable for long-term immunofluorescent cellular imaging.

Owing to their abundant unique properties and ready compatibility with Si microelectronic technology, Si nanostructures are becoming one of the most important classes of nano semiconductors. Particularly, small-sized Si nanoparticles possess distinctive photoluminescence (PL), biocompatibility, and active surface properties. In this review, we focus on the synthesis and PL properties of small-sized Si nanoparticles and their potential applications in the fields of bioimaging and nanocatalysis. We further highlight major challenges and promises in this area.

The use of room-temperature ionic liquids (RTILs) as media for electrochemical application is very attractive. In this work, the electrochemical deposition of silver was investigated at a glassy carbon electrode in hydrophobic 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) and hydrophilic 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) RTILs and in KNO3 aqueous solution by cyclic voltammetric and potentiostatic transient techniques. The voltammograms showed the presence of reduction and oxidation peaks associated with the deposition and dissolution of silver from AgBF4 in both BMIMPF6 and BMIMBF(4), resembling the redox behavior of AgNO3 in KNO3 aqueous solution. A crossover loop was observed in all the cyclic voltammograms of these electrochemical systems, indicating a nucleation process. From the analysis of the experimental current transients, it was shown that the electrochemical deposition process of silver in these media was characteristic of 3D nucleation with diffusion-controlled hemispherical growth, and the silver nucleation closely followed the response predicted for progressive nucleation in BMIMPF6 and instantaneous nucleation in KNO3 aqueous solution, respectively. Compared with these two cases, the electrochemical deposition of silver in BMIMBF4 deviated from both the instantaneous and progressive nucleation models, which could be controlled by mixed kinetics and diffusion. On the basis of the experimental results, it was shown that parameters such as viscosity and water miscibility of RTILs would affect the electrodeposition behavior of silver. Atom force microscopy was employed to probe the surface morphology of the silver deposit, and it showed that the shining electrodeposit of silver was fairly dense and separate nanoclusters of <100 nm were in evidence, corresponding to an island growth model. The strongly enhanced Raman scattering from the monolayer film of 4-mercaptobenzoic acid demonstrated that as-prepared silver nanoparticular film was surface-enhanced Raman scattering (SERS) active. The enhancement factor was calculated to be up to 9.0 x 10(5) and 1.0 x 10(6) for the silver film obtained in BMIMPF6 and BMIMBF4 RTILs, respectively.

TiCT MXene Quantum Dots (MQDs) were obtained with high yield (60%) from two-dimensional MXene via a facile reflux strategy. These green luminescent MQDs possess indisputable and stable annihilation electrochemiluminescence (ECL) and coreactant (TPrA) enhanced (∼29-fold) anode ECL.

Silicon nanoparticle (SiNP) nanocarriers feature strong fluorescence, ultrasmall size, robust photostability, and tunable drug-loading capacity. Using SiNP nanocarriers, the first example of long-term cancer cell tracking is successfully demonstrated. Furthermore, in vivo experiments show that tumor-bearing mice treated with SiNP nanocarriers survive over 20 d without observable tumor growth, demonstrating the high-efficacy chemotherapy of the Si nanocarriers.

The CoO/g-C3N4 p–n heterojunction photocatalysts exhibit enhanced photocatalytic activity and stability under visible light.

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