Towards promoting plant growth and fruit maturation: a highly efficient and thermally stable Cr3+ doped far-red phosphor

Abstract

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, BaGd₂Al₂Ga₂GeO₁₂:Cr³⁺(BGAGG:Cr³⁺), 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.