Color tuning of Eu-Tb co-doped borophosphate glasses for white light through valence state adjustment

The dependence of color points of white light on the composition of borophosphate glasses co-doped with europium (Eu) and terbium (Tb) has been investigated in terms of valence change of rare earth ions. Under ultraviolet (UV) excitation, the white light is observed to be from a combination of 4f65d→4f7 band transition emission at 425 nm for Eu2+, 5D0→7FJ (J=1, 2) line-emissions at 593 nm and 611 nm for Eu3+, and 5D4→7F5 band transition emission at 545 nm for Tb3+. By varying the glass compositi...     

Composition-induced valence variation of europium and the photoluminescence properties for Eu2+ doped borophosphate luminous glass in air

A simultaneous blue-light and red-light emitting glass of SrO-B2O3-P2O5 doped with Eu2O3 is prepared in air, and then heat-treated without any reductive reagent. A transition combination is found to consist of a band emission peaked around 430 nm and a series of line emission from 593 nm to 611 nm, corresponding to the typical 4f65d→ 4f7 transition of Eu2+ and 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions of Eu3+, respectively. Some unidentified crystals such as Sr (PO3)2 and SrB2O4 as hosts for Eu2...     

Fabrication,structure and photoluminescence properties of Eu3+-activated red-emitting Ba2Gd2Si4O13 phosphors for solid-state lighting

Eu^3＋-activated red-emitting Ba2Gd2Si4013 phosphors are prepared via microwave （MW） synthesis and solid-state （SS） method. The structural and luminescent properties of phosphors are investigated by X-ray diffraction （XRD）, photoluminescence （PL） spectra and scanning electron microscopy （SEM）. Upon 393 nm excitation, compared with the sample sintered by SS method, luminescence enhancement is observed in the sample synthesized by MW method. The mechanism of MW synthesis process is discussed in detail. Results indicate that the PL enhancement is probably related to the concave-convex phosphor surfaces and uniform grains, which may reinforce scattering of excitation light. Our research may further promote the understanding of MW synthesis and extend the application of Eu3＋-activated Ba_2Gd_2Si_4O_13 in white light-emitting, diodes.