Correlation between luminescence and structural evolution of colloidal silicon nanocrystals synthesized under different laser fluences

Enhancement in external quantum efficiency of light-emitting diode based on colloidal silicon nanocrystals

Herein, we report an enhanced red emission from colloidal silicon nanocrystals (c-Si NCs) solution-processed light-emitting diode. c-Si NCs were synthesized by facile femtosecond laser ablation. Based on the structural characterization and opto-electrics properties analysis, both photoluminescence and electroluminescence arise from the radiative recombination of carriers due to quantum confined effect. The optical power density and highest external quantum efficiency have been obtained to be 0.79 mW cm^-2and ∼6.6%, respectively. These results indicate that Si NCs are very attractive as a potential optical source for future integrated chips.

First synthesis of silicon nanocrystals in amorphous silicon nitride from a preceramic polymer

We report the first synthesis of silicon nanocrystals embedded in a silicon nitride matrix through a direct pyrolysis of a preceramic polymer (perhydropolysilazane). Structural analysis carried out by XRD, XPS, Raman and TEM reveals the formation of silicon quantum dots and correlates the microstructures with the annealing temperature. The photoluminescence of the nanocomposites was investigated by both linear and nonlinear measurements. Furthermore we demonstrate an enhanced chemical resistance of the nitride matrix, compared to the typical oxide one, in both strongly acidic and basic environments. The proposed synthesis via polymer pyrolysis is a striking innovation potentially allowing a mass-scale production nitride embedded Si nanocrystals.