Solid‐State Route for the Synthesis of Scalable, Luminescent Silicon and Germanium Nanocrystals

Abstract

Group 14 nanocrystals (NCs) have gained significant attention in the last decade largely owing to their unique and tunable optoelectronic properties, allowing for diverse applications across a range of fields. Herein we report a gram‐scale method to prepare Si and Ge NCs from mesoporous metal oxides using a solid‐state metallothermic reduction method. Mesoporous SiO2 and GeO2 were prepared using a templated sol‐gel method. The influence of pore size of the metal oxide precursor and the nature of reducing metal on the formation of Si and Ge was investigated. The NCs were functionalized with dodecyl groups via microwave‐assisted hydrosilylation and hydrogermylation reactions, respectively. Si and Ge NCs were found to have tunable visible or near‐IR luminescence with high emission quantum yields.

Silicon Quantum Dots: Synthesis, Encapsulation, and Application in Light-Emitting Diodes

“…In one approach, mesoporous SiO 2 obtained via template-assisted sol-gel synthesis is reduced using magnesium powder at 500 • C to yield silicon nanocrystals that are reacted with trioctylphosphine oxide to yield hydroxylterminated, encapsulated Si QDs exhibiting red luminescence (Dasog et al, 2012). Free-standing NCs liberated using HF acid and further functionalized with alkyl groups yield NCs that are dispersible in organic solvents with QY up to 48% (Kirshenbaum et al, 2018).…”