PHOTOLUMINESCENCE OF CARBON INCORPORATED SILICA NANOPOWDER FABRICATED USING SUCROSE AS CARBON PRECURSOR

摘要

We demonstrate a very simple method of carbon incorporation in silica nanopowder using sucrose as a carbon precursor. Dehydration of sucrose adsorbed in fumed silica host resulted in formation highly luminescent SiO_2:C nanocomposite. Effects of chemical and thermal dehydration of sucrose molecules as well as carbon content on spectral properties of broad band photoluminescence (PL) and PL relaxation properties were studied. It is shown that carbon incorporation plays a crucial role in formation of light emitting centers but thermal stimulation is not necessary for those centers emitting in near ultraviolet-violet-blue spectral range while formation of green-orange emission centers needs thermally activated reconstruction in the material. Mechanism of white PL in SiO_2:C nanocomposites is discussed in terms of carbon related point defects and carbon nanoclsuters.