Silicon Nanocrystals: It's Simply a Matter of Size

Abstract

Composed of one of the most earth abundant, low cost and least toxic elements, silicon nanocrystals exhibit quantum and spatial confinement effects when their size is diminished to that of the exciton, around 5 nm. With the recent discovery of various means for synthesizing and separating silicon nanocrystals into narrow size distribution mono‐dispersions, it became possible for the first time to implement more deeply analytical studies of their size‐dependent chemical, physical and biological properties than was possible with poly‐dispersions. In this article we take a look at some recent studies of mono‐dispersions of silicon nanocrystals where it is apparent that size really matters. With this newfound knowledge we imagine the new directions that the field may take in the future. The topics covered include how silicon nanocrystal size is manifest on their (i) surface structure and reactivity, (ii) optical and electronic properties, (iii) chemical and photochemical stability, and (iv) biochemical and cytotoxicity behavior. The article concludes with a vision of what the future might hold for this important class of nanocrystals.

Thermal Disproportionation for the Synthesis of Silicon Nanocrystals and Their Photoluminescent Properties

“…As discussed in the previous sections, SiNCs obtained by the thermal disproportionation generally exhibit size-dependent PL which is originated from their intrinsic band-gap (Sun et al, 2016a). The most efficient PL emission often falls within the nearinfrared which fits the biological windows (Sun et al, 2016b).…”

Photoluminescent Nanoparticles for Chemical and Biological Analysis and Imaging

“…Instead, the surface is covalently modified with organic molecules. For hydride-terminated Si NCs, the preferred surface passivation reactions are hydrosilylation, as illustrated in Figure B, whereas for halide-terminated Si NCs, the preferred reactions are those with Grignard and alkyllithium reagents, yielding Si–C bonds in all cases. ,,, Other reactions that introduce Si–O and Si–N bonds ( e.g. , reaction of amines with halide-terminated Si NCs) are also possible; however, these reactions often modify the PL properties. , …”

Multifunctional electrospun polymeric nanofibrous mats for catalytic reduction, photocatalysis and sensing

“…1 From this perspective, high temperatures and pressure, extreme conditions, protec-tive gas environments and tedious procedures were eliminated for the surface-modified and controlled synthesis of the Si QD. [1][2][3] Interestingly, when the (3-aminopropyl)triethoxysilane (APTES) precursor is used, extremely abundant functional groups (e.g., alkoxides, hydroxides, and amine groups) in the aqueous atmosphere seem very suitable environments for progressive chemical organizations such as metal (Pd, Au).…”