Synthesis, structure and photoluminescent properties of far-red Y3Ga5O12:Cr3+ phosphors

Far-red (FR) photosensitive pigment (P_FR) is vital for plant photomorphogenesis. Phosphor-converted (pc) LEDs are the next-generation FR light devices. How to obtain FR-emitting phosphors with a good quantum efficiency, suitable photoluminescence and high thermal stability is still difficult. Herein, we optimize the Y₃Ga₅O₁₂:Cr³⁺ FR phosphor, which has an emission peak at 711 nm and a full width at half maximum of 74 nm, closing to the P_FR absorption band. By adopting the solid-state sintering technology, the internal quantum efficiency reaches 85.5 %, more than 1.5 times higher than that reported by the liquid reaction (55 %). Furthermore, the external quantum efficiency reaches as high as 33.1 %, indicating the promising application in FR-LEDs.