Red emission enhancement in BaYF 5 :Eu 3+ phosphor nanoparticles by Bi 3+ co-doping.

Herein, we report the photoluminescence properties of Bi ³⁺ -sensitized BaYF5:10 mol%Eu ³⁺ nanoparticles. The emission spectra feature Eu ³⁺ peaks corresponding to transitions from the ⁵ D0 excited to ⁷ FJ (J = 1, 2, 3, 4) lower levels with two dominant emissions positioned in the orange-red (∼ 592 nm, ⁵ D0 →  ⁷ F1) and deep-red (∼ 697 nm, ⁵ D0 →  ⁷ F4) regions. Upon 265 nm excitation, the emission intensity increases with an increase of Bi ³⁺ concentration up to 20 mol%. Due to the energy transfer from Bi ³⁺ to Eu ³⁺ ions, the integrated intensity of Eu ³⁺ emission in the Bi ³⁺ co-doped BaYF5:10 mol%Eu ³⁺ is 216% stronger than in the Bi ³⁺ -free sample. Our findings demonstrated that BaYF5:Eu,Bi has potential in plant lighting technology due to strong emission in red and deep-red spectral areas.