A Mn4+-Doped Far-Red-Emitting Phosphor toward Full-Spectrum Lighting

Mn⁴⁺-doped oxide red phosphors exhibit significant potential in full-spectrum lighting and plant growth lighting. Far-red emitting CaLuAlO₄:Mn⁴⁺ phosphor was obtained by a high-temperature solid-phase method. In this structure, Mn⁴⁺ occupies the position of [AlO₆], and exhibits two broad excitation bands in the 250-600 nm range. Upon 365 nm near-ultraviolet excitation, this phosphor exhibits far-red emission near 707 nm. Its internal quantum efficiency and absorptivity were measured to be 55.04% and 81.48%, respectively. CaLuAlO₄:Mn⁴⁺ can compensate for the far-red emission deficiency of WLEDs, attaining a low correlated color temperature (CCT = 3548 K) and a high color rendering index (R_a = 96.5). Plant growth experiments using packaged far-red LED verified its positive effects on plant growth. These results demonstrate the potential of CaLuAlO₄:Mn⁴⁺ red phosphors for applications in full-spectrum lighting and plant growth lighting.