Eu3+-Doped Phosphor-in-Glass: A Route toward Tunable Multicolor Materials for Near-UV High-Power Warm-White LEDs

A novel route toward tunable multicolor materials through phosphor-in-glass (PiG) technology is proposed in this work. Before that, an ultrastable Eu3+-doped precursor luminescent glass frit without thermal quenching in the temperature range of 80-480 K is developed to serve as an encapsulant that not only protects the embedded phosphor but also provides the red-emitting component for the PiG. By adjusting the mass ratio of Sr4Al14O25: Eu2+ phosphor to glass frit, a series of tunable multicolor Eu3+-doped PiG is obtained and exhibits a good resistance to the harsh conditions. Meanwhile, the luminescent color of Eu3+-doped PiG can be modified by changing the excitation wavelength or ambient temperature. Finally, corresponding Eu3+-doped PiG encapsulated high-power light-emitting diodes are further fabricated, especially the warm white-light-emitting diodes (WLEDs), showing good color stability under different drive currents and with different periods of operating time. All these results indicate that Eu3+-doped PiG is a potential color converter applied in the high-power warm-WLEDs and the route above opens up a facile and potential approach to obtain multicolor materials.