Site-specific luminescence of Eu3+ in gel-combustion-derived strontium zirconate perovskite nanophosphors

SrZrO3:Eu3+ nanoparticles with a size of about 100 nm were synthesized by a simple gel combustion route and characterized by X-ray diffraction, scanning electron microscopy, dynamic light scattering, and photoluminescence techniques. Based on the time-resolved emission data, it was inferred that three different types of Eu3+ ions were present in the matrix. The first type was a long-lived species (similar to tau = 6.0 ms) present at symmetric "Sr2+" sites, observed for excitations at 229 and 393 nm. The second was a short-lived species (tau = 1.0 ms) observed for excitations at 229, 296, and 393 nm, while for 296-nm excitation, a long-lived species (tau = 4.0 ms) was also observed. This suggested that Eu3+ ions can be present at relatively lower symmetric "Zr4+" sites with two different environments, which differ in the presence of charge-compensating defects. The color coordinates of the system were evaluated and plotted on a CIE index diagram.