A novel white-light emitting BaBi2Nb2O9: Li+/Tm3+/Er3+/Yb3+ upconversion phosphor

BaBi2Nb2O9:Li+/Tm3+/Er3+/Yb3+ phosphors were successfully synthesized by the high-temperature solid-state method and up-conversion white-light emission has been achieved by tuning of the Tm3+ and Li+ contents. X-ray diffraction and room temperature photoluminescence were used, respectively, to investigate the structural and optical properties of the luminescent systems. Decay dynamics of 4F9/2 levels in BBN:Tm3+/Er3+/Yb3+ and BBN:Er3+/Yb3+ phosphors have been analyzed to study the energy-transfer mechanism between Er3+ and Tm3+ ions. The introduction of Li+ ions into the BBN:0.5%Tm3+0.05%Er3+8%Yb3+ has induced an adjustment of tristimulus values shifting the chromaticity color coordinates of the phosphor towards to the ideal white region (x = 0.31 and y = 0.34). Furthermore, the high color purity white-light coming from the BBN:2%Li+0.5%Tm3+0.05%Er3+8%Yb3+ composition was obtained under moderate power density establishing the BBN phase as a host matrix able to generate RGB with energy saving.