Highly-Efficiency Far-Red Emission in Cr3+ Activated Ca1.8Mg1.2Al2Ge3O12 toward Plant Precise Lighting

Chaowei Yang, Dongwei Zheng, Xikun Zou, Xiangyi Dai, Baoling Tang, Maxim S. Molokeev, Xuejie Zhang, Haoran Zhang, Yingliang Liu, Bingfu Lei// Advanced Optical Materials//


Far-red (FR) region (beyond 700 nm) lighting sources possess special potential for plant lighting. However, it remains a challenge to obtain high-performance Cr3+-doped FR phosphors. This study developed a FR phosphor, Ca1.8Mg1.2Al2Ge3O12:Cr3+ (CMAGG: Cr3+), using the cation substitution strategy. Under 438 nm blue light excitation, the phosphors display FR emission centered at 720 nm with a full width at half maximum (FWHM) of 91 nm. Benefit from the favorable match with the FR phytochrome (Pfr), the phosphor is combined with InGaN blue light chips to create a FR phosphor-converted light-emitting diode (pc-LED), which is used in Italian lettuce growth experiments and it results shown in a 15% increase in fresh weight and a 6.5% increase in dry weight. Notably, supplemental FR light modulated its growth morphology. The results of this study will be useful for further research on novel Cr3+-doped FR phosphors to meet the precise spectral requirements for plant growth.