Highly efficient and thermally stable CaYMgSbO6:Mn4+ double perovskite red phosphor for indoor plant growth.

A novel Mn⁴⁺ activated CaYMgSbO₆ (CYMS) far-red phosphor was synthesized by high temperature solid state reaction. The sample was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), luminescence spectra, ultraviolet-visible spectra, emission-temperature relationship and internal quantum efficiency (IQE). It is found that CYMS:Mn⁴⁺ phosphor has a strong broad excitation band in the range of 200-550 nm. The sample can be excited by ultraviolet and blue light. There is a wide emission band centered at 688 nm between 600 and 760 nm. The optimum doping concentration of Mn⁴⁺ is approximately 0.2 mol%. In addition, all the Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of CYMS:0.002Mn⁴⁺ located in the far-red region. The concentration quenching mechanism is the dipole-quadrupole interaction of Mn⁴⁺ activator. The sample has excellent thermal stability (I_423K/I_298K = 53.2%). Importantly, the CYMS:0.002 Mn⁴⁺ phosphor has an IQE up to 51.5%. Finally, a 365 nm ultraviolet light emitting diode chip combined with CYMS:0.002 Mn⁴⁺ phosphor was used to fabricate the LED device. All the results indicated that CYMS:Mn⁴⁺ phosphors have potential applications in indoor plant cultivation. [ABSTRACT FROM AUTHOR]