Insight into emission-tuning and luminescence thermal quenching investigations in NaLa 1-x Gd x Ca 4 W 2 O 12 :Mn 4+ phosphors via the ionic couple substitution of Na + + Ln 3+ (Ln = La, Gd) for 2Ca 2+ in Ca 6 W 2 O 12 :Mn 4+ for plant-cultivation LED applications.