High-quality reddish-orange-emitting Sr6Y2Al4O15:Eu3+ phosphors for solid-state lighting and anti-counterfeiting applications

Abstract

The reddish-orange emitting Sr6Y2Al4O15:Eu3+ phosphors were synthesized via a high-temperature solid-state reaction technique, and their luminescent properties were systematically studied. The dominant emission peak assigned to the electric dipole transition (5D0 → 7F2) was recorded at 612 nm owing to the non-inversion symmetry of the substituted sites of Eu3+ ions under the excitation of charge transfer band (∼261 nm). The emission of Sr6Y2Al4O15:Eu3+ revealed a Commission Internationale de l'Eclairage (CIE) chromaticity coordinate of (0.571, 0.368) and a color purity of 93.6 %. The thermal stability and photoluminescence quantum yield (PLQY) of Sr6Y2Al4O15: Eu3+ were analyzed, exhibiting a high thermal stability of 88.24 % at 423K and a good external PLQY of 36.24 %. Furthermore, the solid-state lighting (SSL) and flexible anti-counterfeiting applications of Sr6Y2Al4O15:Eu3+ were demonstrated. The red light-emitting diode (LED) was packaged with ∼260 nm ultraviolet LED chip, representing a CIE chromaticity coordinate of (0.5955, 0.3592) and a color purity of 86.53 %. The flexible anti-counterfeiting film was fabricated with polydimethylsiloxane polymer, and it showed tunable emission under different excitations. Moreover, the anti-counterfeiting ink was prepared and printed on various substrates. Consequently, the reddish-orange emitting Sr6Y2Al4O15: Eu3+ phosphors with high color purity, good thermal stability, and high quantum efficiency were introduced and potentially used in SSL and flexible anti-counterfeiting applications.