Far-red-emitting SrGdAlO4:Cr3+,Bi3+ phosphors for plant growth regulation

In modern agriculture, light plays an important role in plant growth. Far red light controls the whole growth process of plants from germination to vegetative growth to flowering. Here, we report the preparation and photoluminescence (PL) performance of Cr,Bi co-doped SrGdAlO 4 phosphors by solution combustion method. The SrGdAlO 4 :Cr 3+ ,Bi 3+ phosphors exhibit far red broadband PL of 660–780 nm excited at 458 nm, and the maximum emission peak position is at 713 nm. It was found Cr 3+ and Bi 3+ replaced the positions of Al 3+ and Gd 3+ in the host material, respectively. The PL performance of SrGdAlO 4 :Cr 3+ ,Bi 3+ phosphors mainly depends on the 2 E 2 → 4 A 2 transition of Cr 3+ , and the addition of Bi 3+ can effectively enhance the PL intensity of the phosphors. Notably, the SrGdAlO 4 :Cr 3+ ,Bi 3+ phosphors also exhibit obvious far red PL when coated onto glass substrate or mixed with plastics without affecting their visible light transmission. We believe our work will excite interests in further exploring the practical application of SrGdAlO 4 :Cr 3+ ,Bi 3+ phosphors as plant growth regulator in greenhouse.