Luminescence properties of Ce-doped ZrO2 phosphors synthesized by combustion method.

ABSTRACT

Zr1-x Cex O2 with x = 0.005, 0.01, 0.02, and 0.03 samples were synthesized using a combustion technique. The X-ray diffraction results revealed that Ce-doped ZrO2 nanoparticles were in a monoclinic structure up to 1 mol% Ce concentration. The increase in the Ce concentration caused more distortion in the monoclinic structure of zirconia. The samples showed a mixed phase (monoclinic + tetragonal) beyond 1 mol% Ce content. The crystallite size (D) and strain (ε) were calculated from the Williamson-Hall equation. The D decreased from 25 ± 1 to 20 ± 1 nm and ε increased from 0.03 to 0.28% with an increase in Ce concentration. Photoluminescence (PL) spectra of Zr1-x Cex O2 showed emission in the blue region under an excitation wavelength of 290 nm. Zr0.995 Ce0.005 O2 showed the highest PL intensity with an average lifetime of 0.93 µs, and the PL intensity decreased with the increase in the Ce concentration. Thermoluminescence (TL) glow curves of Zr1-x Cex O2 were measured after gamma irradiation (500 Gy) with a heating rate of 5 K s-1 . The TL curve of Zr0.995 Ce0.005 O2 showed two prominent peaks at 412 K (peak 1) and 600 K (peak 2). The first TL glow peak was shifted towards a higher temperature at 440 K above 1 mol% Ce concentration. Repetitive TL measurements on the same aliquot exhibited excellent repeatability. Kinetic parameters associated with the TL peaks were calculated using the curve fitting method. Peak 1 followed non-first-order kinetics. The value of the activation energy of the 440 K peak was found to be 0.95 ± 0.01 eV for Zr0.99 Ce0.01 O2 . These findings showed that Zr1-x Cex O2 might be used in lighting and radiation dosimeter applications.