We report on a new kind of white light emitting glass suitable for long-wavelength ultraviolet excitation by simultaneously emitting blue, green and red fluorescence, which is fabricated by melting of Ce(3+)-Tb(3+)-Mn(2+) co-doped borosilicate glass. The spectroscopic properties of singly, doubly and triply doped glasses have been reported and the energy transfer from Ce(3+) to Tb(3+) and Mn(2+) has also been investigated. By adjusting the concentration of different co-dopants, we obtained the ideal white light emitting borosilicate glass with the color coordinate (x = 0.318, y = 0.333).

A simple and practical method for preparing phosphor glass is proposed. Phosphor distribution and element analysis are investigated by optical microscope and field emission scanning electron microscope (FE-SEM). The phosphor particles dispersed in the matrix are vividly observed, and their distributions are uniform. Spectrum distribution and color coordinates dependent on the thickness of the screen-printed phosphor layer coupled with a blue light emitting diode (LED) chip are studied. The luminous efficacy of the 75 μm printed phosphor-layer phosphor glass packaged white LED is 81.24 lm/W at 350 mA. This study opens up many possibilities for applications using the phosphor glass on a selected chip in which emission is well absorbed by all phosphors. The screen-printing technique also offers possibilities for the design and engineering of complex phosphor layers on glass substrates. Phosphor screen-printing technology allows the realization of high stability and thermal conductivity for the phosphor layer. This phosphor glass method provides many possibilities for LED packing, including thin-film flip chip and remote phosphor technology.

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We report on the upconversion luminescence of a pure YVO4 single crystal excited by an infrared femtosecond laser. The luminescent spectra show that the upconversion luminescence comes from the transitions from the lowest excited states 3T1, 3T2 to the ground state 1A1 of the VO4 3-. The dependence of the fluorescence intensity on the pump power density of laser indicates that the conversion of infrared irradiation to visible emission is dominated by three-photon excitation process. We suggest that the simultaneous absorption of three infrared photons promotes the VO4 3- to excited states, which quickly cascade down to lowest excited states, and radiatively relax to ground states, resulting in the broad characteristic fluorescence of VO4 3-.