Enhanced luminescence performance and efficiency of La2NaSbO6: Mn4+ by co-doping Ca2+ for plant growth lighting

A series of La₂NaSb_(1-x)O₆:xMn⁴⁺ (x = 0.001, 0.002, 0.005, 0.008, 0.011, 0.014) and La₂Na_(1-y)Sb_(1-x)O₆:xMn⁴⁺, yCa²⁺ (x = 0.002, 0.005, 0.008, 0.011, 0.014, x:y = 1: 1) phosphors were successfully synthesized by high-temperature solid-state method. Under 365 nm excitation, the phosphor showed an intense emission peak at 700 nm, which can match well with Phytochrome P_FR. By co-doping of Ca²⁺ ions, the photoluminescence intensity of La₂Na_0.992Sb_0.992O₆:0.8%Mn⁴⁺, 0.8%Ca²⁺ phosphor can approach to 1.55 times that of Mn⁴⁺ singly-doping sample and the IQE can achieve as high as 74.18%. Finally, a LED device was fabricated with the optimized phosphor and applied for plant growth lighting, which showed an effective promotion of grow speed of wheat.