Highly efficient and thermostable far-red phosphor for promoting root growth in plants

Abstract

Phytochrome P_FR plays a key role in plant photomorphogenesis, and its perception of far-red light is essential, but how to obtain an efficient far-red phosphor to achieve accurate light filling remains a huge challenge. In this study, Gd_1−y−zAl_3−x(BO₃)₄:xCr³⁺,yLu³⁺,zSm³⁺ (GAB:xCr³⁺,yLu³⁺,zSm³⁺) series phosphors were synthesized by a high-temperature solid-state method. By doping Lu³⁺, the emission intensity of Cr³⁺ could increase as high as 20%. With the introduction of Sm³⁺, the emission intensity of Cr³⁺ was further increased by 29%. Particularly, the emission spectra can be tuned by varying the concentration ratio of Sm³⁺ and Cr³⁺, more suitable for the absorption spectrum of P_FR. Moreover, the internal quantum yield and external quantum yield of GL_0.1AB:0.03Cr³⁺ and GL_0.1AB:0.03Cr³⁺,0.003Sm³⁺ were 83.1% and 24.7% and 78.1% and 26.3%, respectively. There were high anti-thermal quenching properties in the prepared phosphors at 423 K, with 107.6% (GAB:0.03Cr³⁺), 103.1% (GL_0.1AB:0.03Cr³⁺), and 102.7% (GL_0.1AB:0.003Sm³⁺,0.03Cr³⁺). Finally, the phosphors were made into pc-LED devices, which can realize the adjustable orange-red and far-red luminescence and meet the needs of plant lighting applications. In the light-regulated plant growth experiment, compared with the control group, far-red light promoted root growth in plants, confirming the application potential of the prepared phosphors in indoor plant cultivation.