RongFei Wei

Tunable white luminescence and energy transfer in (Cu + ) 2 , Eu 3+ codoped sodium silicate glasses

Luminescent properties of (Cu+)2, Eu3+ single-doped and codoped sodium silicate glasses were systematically investigated by excitation spectra, emission spectra, and decay curves. Due to the efficient energy transfer from (Cu+)2 pairs to Eu3+, varied hues from green to yellowish white and eventually to orange were generated by tuning the content of Eu3+. A perfect white-light emission with CIE coordinates (X=0.336,Y=0.346) was realized in (Cu+)2, Eu3+ and Ce3+ codoped samples. Our research indicates the potential application of (Cu+)2, Eu3+ codoped sodium silicate glasses for converting phosphors for UV LED chips to generate white LEDs.

Enhanced luminescence via energy transfer from Ag + to RE ions (Dy 3+ , Sm 3+ , Tb 3+ ) in glasses

Oxyfluoride glasses containing Ag species and rare earth (RE) ions (Dy(3+), Sm(3+), Tb(3+)) were prepared by melt-quenching technique. The type of luminescent species of novel excitation band (230-300 nm peaked at 255 nm) and emission band (300-600 nm peaked at 350 nm) were investigated by absorption, excitation, emission spectra, as well as decay lifetime measurements and can be ascribed to isolated Ag(+) ions. Owing to energy transfer from Ag(+) to RE ions, significant enhancements of RE ions emission (76 times for Sm(3+), 41 times for Dy(3+)) were observed for non-resonant UV excitation (255 nm). Our research may extend the understanding of interactions between RE ions and Ag species.

Tunable white luminescence and energy transfer in novel Cu + , Sm 3+ co-doped borosilicate glasses for W-LEDs

The luminescent properties of novel Cu⁺, Sm³⁺ single- and co-doped borosilicate glasses were systematically investigated by absorption, excitation, emission spectra and decay curves. Cu⁺ single-doped glasses emit broad luminescence band covering all the visible range. And their peaks shift to blue with decreasing excitation wavelength from 330 to 280 nm. Cu⁺, Sm³⁺ co-doped samples generate the varied hues from blue white to pure white and eventually to yellow white due to an efficient energy transfer from Cu⁺ to Sm³⁺. Our research indicates the potential application of Cu⁺, Sm³⁺ co-doped borosilicate glasses as converting phosphors for white LEDs pumped by UV LED chips.

Preparation, structural and luminescent properties of Ba 2 Gd 2 Si 4 O 13 :Eu 3+ for white LEDs

To find out efficient red phosphors used for white light-emitting diodes (LEDs), a new Ba2Gd2Si4O13:Eu3+ phosphor was prepared by conventional solid-state reaction method. The effect of Li2CO3 flux and Eu3+ doping concentrations on structural and luminescent properties of Ba2Gd2Si4O13 phosphors was studied in detail. The phosphors show intense absorption in near ultraviolet-blue region and exhibit intense red emissions with CIE coordinates of (0.66, 0.34) under 393 nm excitation. The integrated emission intensity of Ba2(Gd0.4Eu0.6)2Si4O13 excited at 393 nm, 362 nm and 464 nm is about 3.5, 4.0 and 3.1 times as that of Y2O3:Eu3+ commercial phosphors, respectively. The excellent luminescent properties and good color saturation make it a promising red phosphor for white LEDs.

Sb3+/Mn2+ co-doped tunable white emitting borosilicate glasses for LEDs.

Luminescent properties of Sb(3+)/Mn(2+) co-doped borosilicate glasses containing no rare earth ions were systematically investigated through absorption, excitation, emission spectra, and decay curves. Upon 250-340 nm light excitation, the glasses exhibit broad blue emission at 400 nm (Sb(3+)) and red emission at 615 nm (Mn(2+)). The varied emitted color from blue through white and eventually to red can be obtained by properly tuning the content of Mn(2+) ions due to energy transfer from Sb(3+) to Mn(2+). Our investigation shows that Sb(3+)/Mn(2+) co-doped glasses may provide a new platform to design and fabricate luminescent materials for UV LED chips in the future.