Luminescence Property of Water Dispersed Porous Si Terminated by Organic Molecules

Abstract

The optical properties of porous Si terminated by various hydrophilic organic molecules were investigated to clarify the influence of the molecular length on the optical properties. In the case of porous Si terminated with hydrophilic organic molecules, surface oxidation of porous Si was restrained and the photoluminescence (PL) properties were more stable than those of the as-prepared sample. The PL of porous Si terminated with organic molecules was caused by the quantum size effect, which was confirmed on the basis of measured PL decay curves. The molecular length of the surface-terminated molecules did not affect the PL properties. Therefore, surface termination with hydrophilic organic molecules is an effective method to improve the stability of the optical properties of porous Si.

Improvement in wettability of porous Si by carboxylate termination

“…In our previous study, PL peaks of as-prepared porous Si (terminated by hydrogen) were located at 750-800 nm. 28) The PL peaks of porous Si were shifted to shorter wavelengths than those of as-prepared porous Si by the hydrosilylation process; PL peaks were located at about 700 nm after propionic acid termination [Fig. 5 indicating that stronger oxidation occurred in the hydrosilylation process with propionic acid.…”