1 research outputs found
Direct Conversion of Hydride- to Siloxane-Terminated Silicon Quantum Dots
Peripheral surface
functionalization of hydride-terminated silicon
quantum dots (SiQD) is necessary in order to minimize their oxidation/aggregation
and allow for solution processability. Historically thermal hydrosilylation
addition of alkenes and alkynes across the Si–H surface to
form Si–C bonds has been the primary method to achieve this.
Here we demonstrate a mild alternative approach to functionalize hydride-terminated
SiQDs using bulky silanols in the presence of free-radical initiators
to form stable siloxane (∼Si–O–SiR<sub>3</sub>) surfaces with hydrogen gas as a byproduct. This offers an alternative
to existing methods of forming siloxane surfaces that require corrosive
Si–Cl based chemistry with HCl byproducts. A 52 nm blue shift
in the photoluminescent spectra of siloxane versus alkyl-functionalized
SiQDs is observed that we explain using computational theory. Model
compound synthesis of silane and silsesquioxane analogues is used
to optimize surface chemistry and elucidate reaction mechanisms. Thorough
characterization on the extent of siloxane surface coverage is provided
using FTIR and XPS. TEM is used to demonstrate SiQD size and integrity
after surface chemistry and product isolation