The Concentration Quenching of Photoluminescence and the Quantum Yield in (Y 1– x Pr x ) 2 O 2 Se Solid Solutions

— (Y 1– x Pr x ) 2 O 2 Se solid solutions with х = 0.004, 0.008, 0.010, 0.012, and 0.020 have been prepared from oxides by ampule synthesis. We have measured their excitation spectra at λ em = 514 nm and their photoluminescence and quantum yield spectra at λ ex = 463 nm ( T = 300 K). Comparing their emission intensities at wavelengths of 514 ( 3 P 0 → 3 H 4 transition) and 670 nm ( 3 P 0 → 3 F 2 transition), we have determined the optimal dopant concentration ( x = 0.01), at which the quantum yield has a maximum, reaching 3%.