Enhanced photoluminescence of Gd2O3:Eu3+ nanophosphors with alkali (M = Li+, Na+, K+) metal ion co-doping

Gd1.95Eu0.04M0.01O3 (M = Li+, Na+, K+) nanophosphors have been synthesized by a low temperature solution combustion (LSC) method. Powder X-ray diffraction pattern (PXRD), scanning electron microscopy (SEM), UV–vis and photoluminescence (PL) measurements were carried out to characterize their structural and luminescent properties. The excitation and emission spectra indicated that the phosphor could be well excited by UV light (243 nm) and emit red light about 612 nm. The effect of alkali co-dopant on PL properties has been examined. The results showed that incorporation of Li+, Na+ and K+ in to Gd2O3:Eu3+ phosphor would lead to a remarkable increase of photoluminescence. The PL intensity of Gd2O3:Eu3+ phosphor was improved evidently by co-doping with Li+ ions whose radius is less than that of Gd3+ and hardly with Na+, K+ whose radius is larger than that of Gd3+. The effect of co-dopants on enhanced luminescence was mainly regarded as the result of a suitable local distortion of crystal field surrounding the Eu3+ activator. These results will play an important role in seeking some more effective co-dopants.

Photoluminescence specta of as-formed (A) Gd2O3:Eu, (B) Gd2O3:Eu:Li, (C) Gd2O3:Eu:Na and (D) Gd2O3:Eu3+:K.Figure optionsDownload as PowerPoint slideHighlights
► Gd2O3:Eu3+ nanophosphors with alkali co-dopants have been prepared by LSC method.
► The phosphors were well characterized by PXRD, SEM, UV–vis, Band gap measurements.
► Effective of co-dopants will play an important role in enhancing the PL intensity.