Photocatalytic Activity and Optical Properties of Blue Persistent Phosphors under UV and Solar Irradiation

Figure 4

Plot of the Kubelka-Munk functions versus energy in eV for all samples annealed at different temperatures. The dashed lines are the tangent lines related to the procedure for the estimation of the band-gap energy; the intersection of the dashed lines with the horizontal axis gave us the values of the band-gap energy.