Towards promoting plant growth and fruit maturation: a highly efficient and thermally stable Cr doped far-red phosphor

Far-red light plays a crucial role in plant growth, development, and flowering as a light signal. However, efficiently obtaining far-red light that well-matches the plant-photosensitive pigment P fr remains a significant challenge in indoor agriculture. In this study, a far-red phosphor, BaGd 2 Al 2 Ga 2 GeO 12 :Cr 3+ (BGAGG:Cr 3+ ), was successfully synthesized, using a high-temperature solid-phase method. Under 450 nm excitation, its emission maximum is at 712 nm with a full width at half maximum (FWHM) of 92 nm, which well-matches with P fr . Combined with a blue LED chip, this phosphor was used to create a pc-LED device for bok choy and Micro-Tom cultivation experiments. Under the irradiation of far-red light, the biomass of bok choy increased by 39%, and the flowering and fruiting of Micro-Tom was promoted, demonstrating its potential in plant lighting applications. A new type of efficiency and low thermal quenched BGAGG: 0.07Cr 3+ far-red phosphor was synthesized and used to prepare far-red pc-LED for plant lighting. Its positive effects were demonstrated in cultivation experiments of bok choy and Micro-Tom.