Room Temperature Hydrosilylation of Silicon Nanocrystals with Bifunctional Terminal Alkenes

Abstract

H-terminated Si nanocrystals undergo room temperature hydrosilylation with bifunctional alkenes with distal polar moieties—ethyl-, methyl-ester or carboxylic acids—without the aid of light or added catalyst. The passivated Si nanocrystals exhibit bright photoluminescence (PL) and disperse in polar solvents, including water. We propose a reaction mechanism in which ester or carboxylic acid groups facilitate direct nucleophilic attack of the highly curved Si surface of the nanocrystals by the alkene.

Controlled Styrene Monolayer Capping of Silicon Nanocrystals by Room Temperature Hydrosilylation

“…25 If the hydrideterminated Si nanocrystals are mixed with styrene and heated to 140°C under nitrogen, a yellow gel of polystyrene-embedded Si nanocrystals is obtained, similar to what has recently been reported by Veinot and co-workers. 17 To achieve styrene monolayer passivation without significant styrene polymerization, the hydrosilylation reaction must be carried out at room temperature.…”

Fluorescent sensor for Cr(VI) based in functionalized silicon quantum dots with dendrimers

“…These synthesis yield Si-H bonds in the surface being susceptible of degradation by oxidative processes in aqueous media, therefore its surface stabilization is necessary to preserve their optical properties [31,33]. The most used methods for this stabilization are based in hydrosilation/polymerization reactions catalyzed by thermal or UV processes, or reactions with alkene terminal groups [34][35][36]. Other methods are based in the direct functionalization using the Zintl salt, a method to obtain by direct reaction of nucleophilic groups with NaSi, MgSi or KSi, which are strong electrophilic systems [37].…”

Low Temperature Colloidal Synthesis of Silicon Nanorods from Isotetrasilane, Neopentasilane, and Cyclohexasilane

“…The PL emission quantum yield of these nanorods dispersed in toluene at room temperature was 2%. Generally, the absorbance and emission 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 spectra of these Si nanorods are similar to alkene-passivated Si nanocrystals [22][23][24][25] and Si nanorods made at higher temperature with trisilane and Sn seeds particles. 3 Figure 4d shows the timedependent PL decay.…”