Absorption, luminescence and ESR spectra of yttria-stabilized zirconia

This paper reports that absorption and luminescence bands of undoped (YSZ)ZrO2-Y2O3 (88:12 mole%) are due to color centers. In the absorptions of YSZ:Ce,Co,Cr and Er, one sees beside the absorption edge of undoped YSZ the characteristics transition bands Ce3+, Co2+, Cr3+ and Er3+ ions, respectively. The crystal color of YSZ:Co is from violet to blue under different oxireductive conditions. Co(ppm) as a complementary color agent can eliminate the parti-color of the raw material or the parti-color introduced during the growth process. New absorption band will appear for such crystals doped with Ce or Co, because of Ce4+ changing into Ce3+ during irradiation. YSZ color center emission intensity in 400-600nm region are decreased due to self-absorption of Ce and Co impurities in the crystals. The changes in Ce and Co valence state were deduced from the changes in ESR signal of the single charged (YZr, V0)' free spin and Fe3+ ions, and were compared with their absorption spectra