Band structure, energy transfer and temperature-dependent luminescence of novel blue emitting KBaYSi2O7:Eu2+ phosphor

• A novel blue-emitting Eu2+-doped KBaYSi2O7 phosphor has been synthesized.
• Band structure of the host material were calculated based on the first principle.
• Energy transfer and temperature-dependent luminescence properties were discussed.

A novel blue-emitting Eu2+-doped KBaYSi2O7 phosphor has been synthesized by conventional high temperature solid-state reaction. The crystal structure, luminescent properties, energy transfer and thermal stability of the as-prepared samples were studied systematically by X-ray diffraction (XRD), fluorescent dynamics, photoluminescence (PL) including temperature-dependent luminescence. The KBaYSi2O7:Eu2+ phosphor exhibits an intense and broad excitation band ranging from 250 to 400 nm in the near ultraviolet region and produces a bright blue emission band with the CIE chromaticity coordinates of x = 0.139 and y = 0.146 under the excitation of 342 nm, which were ascribed to the 4f–5d transitions of Eu2+. The optimal doping concentration of Eu2+ in KBaYSi2O7 phosphor was confirmed to be around 4 mol% and the concentration quenching mechanism of Eu2+ ions was dominated by the dipole–dipole interaction. It is observed that the fluorescent lifetimes of samples decrease with increasing Eu2+ content because of the increase of energy transfer rate among Eu2+ ions. The thermal stability of luminescence of KBaYSi2O7:Eu2+ phosphor was also investigated and the activated energy was deduced to be 0.123 eV, which shows good thermal stability. The above results indicate that Eu2+-doped KBaYSi2O7 phosphor may have a potential application as a NUV convertible blue emitting phosphor for white LEDs.

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