Controlling the energy transfer via multi luminescent centers to achieve white/tunable light in a single-phased Sc2O3:Bi3+,Eu3+ phosphor

Abstract

In recent years, single-phased white light-emitting phosphors that can be excited by ultraviolet (UV) light are considered as a type of highly important materials for white light-emitting diodes (wLEDs). In this work, we report on a kind of single-phased Sc2O3:Bi3+,Eu3+ phosphor, which enables generating white/tunable light upon excitation at 331 nm. Our structural analysis reveals that the Sc2O3 crystal host has three different Sc3+ sites, which, as the emission spectra reveal, will lead to three different Bi3+-related luminescence centers (i.e., ~356 nm for Bi1, ~407 nm for Bi2, and ~489 nm for Bi3). The latter two Bi3+-related photoemission bands have been shown to cover the spectral region from 380 to 700 nm. Since the Sc2O3:Bi3+ phosphor lacks enough red-emitting component, the red-emitting Eu3+ component, thus, is co-doped into, aiming to achieve the white light through controlling the energy transfer efficiency from Bi3+ to Eu3+. Specifically, the emission colors, which can be tuned from blue, white and to red, are found to depend on the Eu3+ content. The tunable emission mechanism, which bases on the energy transfer from Bi3+ to Eu3+, is o constructed to illustrate our experimental photoluminescence (PL) results. This work not only adds a new member into the family of tunable phosphor, but also can provide new insight into discovering more single-phase white light phosphor in the future.