Self-assembly and characterization of novel amorphous SiOx (x=2.1) nanospheres

We report the self-assembly and characterization of amorphous SiOx nanospheres with diameters 210-240 nm. The preparation method was based on hydrolysation-induced self-assembly with Na2SiO3 as the silica precursor and polyacrylamide gels as the template. Ultraviolet and blue-green photoluminescence were observed at room temperature from amorphous SiOx nanospheres. The photoluminescence spectrum has peaks at 400 and 530 nm. From the x-ray photoelectron spectroscopy and energy disperse x-ray spectroscopy we found that the atomic ratio of Si to O is about 1: 2.1. From the infrared spectrum and x-ray photoelectron spectroscopy, we suggest that the origin of the stable emission is Si-OH complexes located on the surface of the nanospheres. The silica nanospheres may have potential applications in future integrated optical devices.