White light emission from γ-irradiated Ag/Eu co-doped phosphate glass under NUV light excitation

We reported on a new white light emission phosphor from γ-irradiated Ag/Eu co-doped phosphate glass 65NaPO3–30Al (PO3)3–5SiO2. Absorption and EPR results confirm the appearance of Eu2+ and silver aggregates (Ag2+ and Ag32+) after γ-irradiation. Ag2+ and Ag32+ show strong absorption in near ultra-violet (NUV) range with a maximum at 320 and 370 nm, respectively. Energy transfers of silver aggregates → Eu2+, silver aggregates → Eu3+ and Eu2+ → Eu3+ greatly enhanced luminescence intensity of Eu2+ and Eu3+ after γ-irradiation. The white light emission can be tuned simply by changing excitation wavelength. Pure white light emission close to standard white light (x = 0.333, y = 0.333) in CIE chromaticity diagram was obtained under 337–385 nm excitation. Pure white emission, broad excitation bands and easy fabrication suggest its potential application in white LEDs.

As shown in this figure, white luminescence was obtained from (-irradiated Ag/Eu co-doped phosphate glass under UV light excitation. Especially, at 337–385 nm UV excitation, the relative pure white light emission is obtained and the chromaticity coordinate is close to standard white light (x = 0.333, y = 0.333) in CIE chromaticity diagram.Figure optionsDownload as PowerPoint slideHighlights
► White light emission from γ-irradiated Ag/Eu co-doped phosphate glass.
► The energy transfer from silver aggregates to Eu2+ ions.
► Gamma irradiation induced silver aggregates and Eu2+ ions in phosphate glass.
► Enhanced UV-excited luminescence of europium ions.
► Tunable luminescence properties of γ-irradiated Ag/Eu co-doped phosphate glass.