Colloidal silicon quantum dots: synthesis and luminescence tuning from the near-UV to the near-IR range

Abstract

This review describes a series of representative synthesis processes, which have been developed in the last two decades to prepare silicon quantum dots (QDs). The methods include both top-down and bottom-up approaches, and their methodological advantages and disadvantages are presented. Considerable efforts in surface functionalization of QDs have categorized it into (i) a two-step process and (ii) in situ surface derivatization. Photophysical properties of QDs are summarized to highlight the continuous tuning of photoluminescence color from the near-UV through visible to the near-IR range. The emission features strongly depend on the silicon nanostructures including QD surface configurations. Possible mechanisms of photoluminescence have been summarized to ascertain the future challenges toward industrial use of silicon-based light emitters.

Synthesis, Optical Characterization, and Size Distribution Determination by Curve Resolution Methods of Water-Soluble CdSe Quantum Dots

“…For TGA-capped QDs a NIR (near infra-red) emission could be related to the surface-defects that generate shallow levels near the valence band, that acts as traps for photogenerated holes. 46,47 The obtained results agreed with literature data presented for CdTe QDs obtained in aqueous medium and bearing GSH, MPA, TGA, and TGH as surface ligands. .…”

Silicon‐Based Dielectric Metamaterials: Focus on the Current Synthetic Challenges

“…Most synthetic protocols produce Si terminated with either hydrides,oxides or halogens.Thiols have also been used as capping ligands for Si nanocrystals,a lthough the passivating layer is very susceptible to degradation by hydrolysis. [121][122][123] 3) Silanization is generally am ulti-step reaction:f irst of all, the surface has to be modified with an alcohol and then treated with degassed H 2 Ot od ecorate the surface with hydroxyl terminal groups.O Ht erminated nanoparticles then react with siloxane to form ac ore-shell Si@siloxane. Silyl radicals react with the terminal carboncarbon bond to induce as table SiÀCb ond.…”

Silicon Nanocrystals: From Indirect to Direct Bandgap

“…In analogy to Figure , Figure summarizes the behavior of PL maximum and for SiNCs:C. Looking at this figure, one can immediately see that at least two classes of materials exist, namely SiNCs:C with slow red and those with fast blue emission. An observation about the existence of these two emission modes has already been made by many authors . Also, its connection to the preparation method has been suggested, as illustrated in Figure .…”

“…An observation about the existence of these two emission modes has already been made by many authors . Also, its connection to the preparation method has been suggested, as illustrated in Figure . According to this interpretation, high‐temperature methods, such as the annealing‐based ones, yield slowly red‐emitting SiNCs:C, whereas low‐temperature methods, typically chemical syntheses, lead to the fast blue‐emitting SiNCs:C.…”