An efficient synthesizing procedure of photoluminescent silicon nanocrystals is demonstrated by means of ultrasound assisted electrochemical octyl trichlorosilane reduction that produces octane terminated Si nanocrystals in a single step. The described procedure allows one to make Si nanocrystals with alkyl surface termination and is clean, relatively simple, and potentially scalable to industrial quantities. High resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, UV-vis absorbance, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy are employed to characterize the synthesized photoluminescent Si nanocrystals. Resulting octyl termination provides a stable passivation and could serve as a platform for further particle functionalization. Electrochemical chlorosilane reduction potentially could address the requirement for stable photoluminescent Si nanocrystals in diverse applications.