Structural, electronic and optical properties of prominent M2Si5N8:Eu2+ phosphors (M = Mg, Ca, Sr, Ba) from the ground–state and excited–state first principles calculations

Nearly‐Unity Quantum Yield and 12‐Hour Afterglow from a Transparent Perovskite of Cs2NaScCl6:Tb

“…Afterglow phosphors are capable of energy storage for photons in a broad wavelength range from X-ray, ultraviolet, to visible light, spurring a magnitude of applications in display, [1] excitation-free bioimaging [2] and optical-information encryption. [3] Certain, oxide-, sulfide-, and nitridebased afterglow phosphors, such as SrAl 2 O 4 : Eu 2 + , Dy 3 + , [4] ZnS : Cu,Co, [5] and M 2 Si 5 N 8 : Eu 2 + (M = Mg, Ca, Sr, Ba) [6] exhibit both high afterglow intensities and ultra-long durations up to several days or even weeks. [7] However, these phosphors have a high lattice energy, which requires a calcination procedure to form the target phase.…”

“…As a consequence, unwanted agglomeration occurs during synthesis, leading to a severe scattering issues from conventional phosphor powders. [4][5][6] Therefore, there use in many advanced techniques, such as volumetric display and threedimensional encryption, were hindered due to the lack of a transparent afterglow matrix. [8] To date, few attempts have been devoted to making transparent afterglow materials at low temperature.…”

“…However, these phosphors have a high lattice energy, which requires a calcination procedure to form the target phase. As a consequence, unwanted agglomeration occurs during synthesis, leading to a severe scattering issues from conventional phosphor powders [4–6] . Therefore, there use in many advanced techniques, such as volumetric display and three‐dimensional encryption, were hindered due to the lack of a transparent afterglow matrix [8] …”