Photoluminescent properties of porous silicon nanoparticles: synthesis, characterization, and cellular imaging

Abstract

Purpose: This study investigates the stability of photoluminescent (PL) properties of microporous silicon nanoparticles (μpSi-NPs) synthesized by electrochemical etching of monocrystalline silicon followed by lyophilization.Experimental: Structural analysis revealed a highly porous architecture with < 2-nm pores and silicon nanocrystals (nc-Si) with an average size of 3–5 nm. Fourier-transform infrared spectroscopy confirmed the presence of Si-O-Si bonds, indicating surface oxidation of nc-Si. PL studies demonstrated a broad emission band peaking at 685 nm, attributed to exciton recombination in nc-Si. After 5 months of storage, the PL peak shifted to 655 nm, reflecting oxidation-induced size reduction of nc-Si. Raman spectra showed a 1.5 cm–¹ shift of the Si phonon peak along with spectral broadening, evidencing phonon confinement and partial amorphization. XANES analysis further confirmed increased suboxide content and structural disorder.Conclusions: Biological experiments demonstrated the biocompatibility of μpSi-NPs and retention of their PL activity, highlighting their potential for biomedical applications such as bioimaging and biosensing