We have measured site-selective luminescence spectra of EU(3+) in the
perovskite proton conductors Y3+-doped SrCeO3 single crystals. A stron
g red shift of the D-5(0)-F-7(0) transition of EU(3+) is observed with
H2O-treatment. The site-selective spectra of these reveals that (i) f
our different sites of EU(3+) ions exist in protonated SrCeO3 system a
t row Y3+ concentration and (ii) that the relative intensity among the
se sites strongly depends on the dopant concentration.