Highly efficient photoluminescence of SiO2 and Ce-SiO2 microfibres and microspheres.

Semiconductor nanocrystals and nanostructures have been extensively studied in the last few years due to their interesting optical and optoelectronic properties. Nevertheless, combining precise photoluminescence properties with controlled morphologies of SiO2 is a major hurdle for a broad range of basic research and technological applications. Here, we demonstrate that microemulsion droplet interfacial elasticity can be manipulated to induce definite morphologies associated with specific intrinsic and extrinsic photoluminescent defects in the silica matrix. Thus, under precise experimental conditions hollow crystalline and compact amorphous SiO2 spheres showing ultraviolet-photoluminescence and helicoidal fibrils of Ce-doped amorphous silica with violet-blue emissions are obtained. Overall, it is demonstrated that the combination of microemulsions and doping represents an easy strategy for the design of specific nanoscale structures with high efficiency photoluminescence. The detailed structural analysis provided in the present work is expected to be useful as accurate information on assessment of technological nanostructures.