Cationic Silicon Nanocrystals with Colloidal Stability pH‐Independent Positive Surface Charge and Size Tunable Photoluminescence in the Near‐Infrared to Red Spectral Range

摘要

In this report, the synthesis of a novel class of cationic quaternary ammonium‐surface‐functionalized silicon nanocrystals (ncSi) using a novel and highly versatile terminal alkyl halide‐surface‐functionalized ncSi synthon is described. The distinctive features of these cationic ncSi include colloidal stability, pH‐independent positive surface charge, and size‐tunable photoluminescence (PL) in the biologically relevant near‐infrared‐to‐red spectral region. These cationic ncSi are characterized via a combination of high‐resolution scanning transmission electron microscopy with energy‐dispersive X‐ray analysis, Fourier transform infrared, X‐ray photoelectron, and photoluminescence spectroscopies, and zeta potential measurements.