Novel orange–red emitting phosphor Sr8ZnY(PO4)7:Sm3+ with enhanced emission based on Mg2+ and Al3+ incorporation for plant growth LED lighting

In this paper, a series of novel orange-red emission phosphors Sr8ZnY(PO4)7:Sm3+ (SZYP:Sm3+) were synthesized by high-temperature solid-state reaction. The photoluminescence and concentration-dependent properties of this phosphor were investigated carefully through diffuse reflection spectra, excitation and emission spectra, Commission Internationale de l'Éclairage (CIE) chromaticity coordinate and decay times. SZYP:Sm3+ could be efficiently excited by n-UV and blue lights which center at 318, 345, 363, 376, 401, 410, 440 and 475 nm, respectively. The characteristic orange-red emission peaking at 563, 601 and 647 nm had been detected, which should be attributed to the characteristic f–f forbidden transition of Sm3+. The internal quantum efficiency (IQE) of ideal phosphor of SZYP:0.09Sm3+ reached as high as 47%. In addition, The concentration quenching mechanism and thermal stability of SZYP:Sm3+ were further investigated. It was found SZYP:Sm3+ can maintain 93% of initial emission intensity at 150 °C and the corresponding activation energy was calculated to be 0.26 eV based on Arrhenius formula. The emission intensity of 1.0Mg2+ and 0.02Al3+ incorporated SZYP:0.09Sm3+ reached up to 134% and 117% of the initial value, respectively. Moreover, (light-emitting diodes) LED devices were fabricated by employing the optimized samples as orange-red component with 365 nm n-UV chips. The desired emission in plant absorption region and extremely high thermal stability imply that SZYP:Sm3+ is suitable for the application in plant growth LED lighting.