Narrow-band far red-emitting double-perovskite SrGd2Al2O7:Mn4+ phosphors

Accurate light irradiation towards phytochrome has been considered as a key method to improve the efficiency of plant cultivation. In this work, a series of far red-emitting Mn4+-activated SrGd2Al2O7(SGAO) phosphors were synthesized by high temperature solid-state reaction. Under excitation at 330 nm, the optimized SGAO:0.1%Mn4+ phosphor exhibits intense far-red emission in narrow range of 701–740 nm, which matches well with the absorption of phytochrome PFR and excludes from that of the phytochrome PR. Moreover, the SGAO:0.1%Mn4+ sample exhibits considerable thermal quenching of far-red emission towards temperature, the emission intensity around 719 nm at 423 K was approximately 33% of that at room temperature. Also, the crystal field strength Dq, the Racah parameters B and C, and the nephelauxetic ratio β1 of SGAO: Mn4+ were calculated and discussed. The results provide a reference for developing new high-efficient far-red-emitting phosphor towards indoor plant growth LEDs.