Synthesis of Sr₄Al₁₄O₂₅:Eu²⁺ green emitting luminescent nano-pigment by solution combustion method

Luminescent nano-pigments based on strontium aluminates doped with various amounts of europium rare earth ion (Sr₄Al₁₄O₂₅:Eu²⁺) were synthesized by solution combustion method which involves the exothermic reaction of an oxidizer and an organic fuel. It is a suitable method for producing chemically homogenous and pure powders with very fine particle size. Phases studies by X-ray diffractometer indicated formation of pure phase Sr₄Al₁₄O₂₅ with crystallite sizes about 52.46 nm and peak shift of about 2θ = 0.26° due to Eu²⁺ doping. scanning electron microscope micrographs also revealed that the particles have irregular morphology and wide particle size distribution. The emission spectrum showed main emission peak at about 480 nm. Energy transfer mechanism between the two emission centers and the effect of Eu²⁺ ion concentration on emission spectrum was studied and it was deduced that the maximum emission intensity occurred at 4 at% of Eu²⁺. Absorption spectrum of the samples were lower than 0.5 %, especially in emission region of the doped pigments.