Effect of Environments on Optical Properties of Chemically Prepared Si Nanoparticles

Silicon (Si) nanoparticles were synthesized by chemical etching process at ambient temperature. Field emission transmission electron microscopy (FE-TEM), Fourier transforms infrared spectroscopy (FTIR), UV/Vis absorption and photoluminescence (PL) spectroscopic techniques were employed to examine the morphological structure and optical features of the synthesized Si nanoparticles. Effect of solvent and temperature on optical properties of Si nanoparticles is presented. We believe that at physiological pH Si nanoparticles have charged surface, because of high solubility in organic solvents. Experimental results show that the Si nanoparticles are a good biocompatible, non-agglomerated, homogeneously well distributed and highly dispersible in organic solvents. The emission and absorption properties of Si nanoparticles were tuned by altering the environment (solvents) through electrostatic interaction of various organic solvents with the Si nanoparticles. The band shapes of the Si nanoparticles show remarkable changes on passing from non-coordinating solvent (chloroform) to various coordinating solvents which is the result of change in the environment around Si nanoparticles in the various solutions and suggests coordination of solvent molecule(s), in some cases. The results clearly show that among the solvents studied DMSO is the most effective in promoting the efficient emission intensity.