Tailoring B-doped silicon nanocrystal surface chemistry via phosphorus pentachloride – mediated surface alkoxylation

Abstract

Doped silicon nanocrystals (SiNCs) are promising materials that could find use in a wide variety of applications. Realizing methods to tailor the surface chemistry of these particles offers greater tunability...

Post-Synthesis Boron Doping of Silicon Quantum Dots via Hydrosilsesquioxane-Capped Thermal Diffusion

“…Previously, we observed that when doping levels exceed the solid solubility limit of B in Si (i.e., > 9.0  10 -4 atomic % B below 700 °C) 85,86 two B species appear in the XPS analysis that correspond to 'surface' and 'core' B dopants. 87 The same trend appears for the present systems. Figure 2 shows the highresolution B 1s XP spectra for SiQDs (pre-formed intrinsic SiQDs dTEM = 6.3 ± 1.2 nm) prepared at indicated peak annealing temperatures in the range of 400 -600 °C in a flowing Ar (Figures 2 a-c) and 5% H2:95% Ar (Figures 2 d-f) atmospheres.…”

“…Further confirming 1-decylate functionalization, the high-resolution B1s XP spectra of all functionalized SiQDs show evidence of an emission at 192 eV that we attribute to oxidized four-coordinate B bonded to two or three Si atoms and one or two "OR" functionalities at the SiQD surface which are not observed for non-functionalized Bdoped SiQDs (Figure S14). 39,87,89,105 In addition, Si 2p high-resolution XP spectra show increased relative intensity of the Si(III) and Si (IV) species at binding energies of 102 and 103 eV, respectively that is consistent with introduction of alkoxide surface ligands (Figure S15).…”

“…These observations are consistent with other reports of doped SiQDs that did not require additional surface functionalization to render them compatible with polar solvents. 40,87,89 Looking to the infrared spectra of the doped SiQDs (Figure S8 a) features at 1400 cm -1 that are characteristic of B-O/B-H stretching are clearly present while equivalent analysis of the preformed intrinsic SiQDs show no evidence of B-related absorptions while Si-H related features (i.e., 900 and 2200 cm -1 ) dominate the spectra.…”

“…Recently, we demonstrated the surface chemistry of B-doped SiQDs is readily tailored using a two-step approach involving phosphorus pentachloride (PCl5) etching followed by heating in the presence of an appropriate alcohol that binds to the particle surface as an alkoxide ligand. 87 To investigate the potential size dependence of this functionalization procedure, we functionalized B-doped SiQDs of different sizes/B-doping concentrations (i.e., 3.66 ± 0.85/5.03 atomic %, 4.38 ± 0.91/3.83 atomic %, and 7.10 ± 1.6 nm/2.49 atomic %) with 1-decylate surface groups derived from 1-decanol and evaluated their size-dependent optical response. After functionalization, all the presented SiQDs readily disperse in common organic solvents (e.g., toluene) to yield a transparent yellow/brown 'solutions' that show a Tyndall effect when exposed to the emission of a standard laser pointer (Figure S13 a).…”

Experimental Study of the Influence of CH4 and H2 on the Conformation, Chemical Composition, and Luminescence of Silicon Quantum Dots Inlaid in Silicon Carbide Thin Films Grown by Remote Plasma-Enhanced Chemical Vapor Deposition

“…Experimental and theoretical studies have shown that quantum confinement effects (QCEs) are largely responsible for the observed PL. − Luminescence from the nanostructured silicon has a vast number of applications. Therefore, systems conformed by silicon quantum dots (SiQDs) embedded in silicon-based matrixes have been of great interest for the scientific and technological community in recent years. − …”