A novel orange-red emitting K5Y(MoO4)4:Sm3+ phosphor with excellent color purity for temperature sensing and high CRI WLEDs

Abstract

The novel orange-red emitting K5Y(MoO4)4:xSm3+ (KYMO:xSm3+) (1 mol% ≤ x ≤ 35 mol%) phosphors were synthesized through solid-phase reaction. The KYMO:Sm3+ phosphors were mainly analyzed for purity phase, luminescence properties, and thermostability. Under 403 nm excitation, KYMO:10 mol%Sm3+ possesses four distinct emission peaks. The dominant emission peak is situated at 645 nm, corresponding to the 4G5/2 → 6H7/2 electron transitions. With x = 10 mol%, the KYMO:xSm3+ phosphor has the optimal doping concentration. The color purity reaches as high as 99.9 %. KYMO:10 mol%Sm3+ presents good thermostability with T0.5 > 480 K and resistance to color drift (ΔE = 0.012 at 420 K). The lifetime for KYMO:10 mol%Sm3+ is 1.16 ms. The internal quantum efficiency (IQE) reaches 62.74 %. At 480 K, the maximum temperature sensing sensitivities of the FIR of I564/I599 are 5.19 × 10−4 (Sa) and 18 % (Sr). The assembled WLED displays an excellent color rendering index (CRI, Ra) of 94, Commission International de L′ Eclairage (CIE) coordinates (0.333, 0.346), and a correlated color temperature (CCT) of 5464 K. In summary, KYMO:Sm3+ phosphors possess great promise for high CRI white-light-emitting diodes (WLEDs) and potential feasibility for temperature sensing.