Preparation And Property Regulation Of Cr³⁺-doped Gallate Phosphors For Plant Cultivation

Phytochromes P_Rand P_FRin plants can effectively regulate their growth after absorbing LED light near 660 nm and 730 nm,such LEDs can be realized by coating deep/far red phosphors on UV/near UV/blue light chips.Cr³⁺can emit red light in the range of 650-1600nm,which is very suitable for the preparation of deep/far red luminescent material.Firstly,Zn Ga₂O₄was chosen as the matrix and deep-red gallate phosphors Zn Ga₂O₄:Cr³⁺were synthesized rapidly by microwave radiation method.Phosphors were systematically studied from the perspective of calcination temperature,time and Cr³⁺concentration.At the same time,x Li⁺→x Zn²⁺substitution was tried to introduce defects and abnormal thermal quenching was realized at high temperature.Secondly,far-red gallate phosphors Gd₃Ga₅O₁₂:Cr³⁺were prepared and x Y³⁺→x Gd³⁺,x Lu³⁺→x Gd³⁺substitution were tried,the luminescence intensity and thermal stability of the phosphors were effectively improved after doping.Bi³⁺was doped into Gd₃Ga₅O₁₂:Cr³⁺and Cr³⁺emission was enhanced by realizing Bi³⁺→Cr³⁺energy transfer.The reason for the variation of luminescence intensity was systematically studied.Finally,optimized phosphors were demonstrated to have potential application in plant cultivation.