Europium nitrate, obtained from Eq. (1) and solution containing
stoichiometric amounts of calcium nitrate, bismuth nitrate, silica
fumes and DFH are taken in a cylindrical Petri dish of approximately
300 ml capacity. The homogeneous solution was continuously
stirred using magnetic stirrer to get homogeneous redox
mixture. Then the Petri dish containing the redox mixture was
introduced into a muffle furnace maintained at 500 ± 10 C. The
reaction mixture undergoes thermal dehydration and auto-ignites
with liberation of gaseous products such as oxides of nitrogen and
carbon. The combustion flame propagates throughout the reaction
mixture. The heat of reaction is sufficient for the decomposition of
the redox mixture and to form the desired product. The whole process
was completed in less than 5 min and a highly porous white
Ca0.96xEu0.04BixSiO3 nanopowders were obtained. Different samples
of Ca0.96xEu0.04BixSiO3 were prepared using the above procedure.
The bismuth concentration was varied systematically
between x = 0.01 and 0.05, to correlate co-dopant effect with optical
properties of the phosphors.