The concentration dependence curves of several
Eu‐+3
,
Tb‐+3
, and
Pr‐+3
activated phosphors for different excitations have been studied. The optimum activator concentration was found to be a function of the number of excited activator ions as well as the exciting wavelength. For exciting radiation having a high absorption coefficient, the optimum activator concentration of a given phosphor shifted to low concentration. The concentration dependence curves of
false(Y1−xEux)2O3
and
false(Y1−xPrx)2O2S
phosphors under cathode‐ray excitation are almost identical to the curves obtained with host photoexcitation.
The luminescent properties of the green emitting
Y2O2S:Pr+3
have been studied. The emission lines in the visible region are assigned to the transitions from 3P0 to 3HJ and to 3F2 of Pr+3; the main green emission lines around 514 nm are attributed to the transition
3P0→ 3H4
. There was a small shift, about 160 cm−, of the emission lines to higher energy with an increase in host cation radius (Y to Gd to La). The two broad excitation bands in
Y2O2S:Pr+3
, centered at 255 and 290 nm, are due, respectively, to host excitation and to excitation associated with an interaction of activator and host. The optimum activator concentration of
Y2O2S:Pr+3
phosphor is at about
1×102 mole Pr2O2S
per mole of phosphor. Quadrupole‐quadrupole interaction is involved in the concentration quenching of the green emission. * Electrochemical Society Active Member.
Emission and absorption spectra of the alkaline earth sulfides activated with europium and fired in a neutral atmosphere have been re-investigated. The emission and absorption spectra of the alkaline earth oxides, also activated with Eu, and fired in a neutral or a reducing atmosphere have been obtained. The sulfides show both band emission and band absorption, as does SrO fired in hydrogen. The other hydrogen-fired oxides have band absorption, except for MgO, and give either mixed band and line emission or only line emission. The nitrogen=fired oxides, except MgO, give line emission and little, if any, selective absorption. MgO emits a broad line spectrum for both the nitrogen-and hydrogen-fired samples and shows no absorption peaks. Emission and absorption spectra have been correlated with the oxidation state of the activator in the several phosphors, the line emissions being associated with the presence of Eu +a and the band emissions with Eu +2.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.