Multifunctional Near-Infrared Phosphors Cr3+/Ni2+ Codoped Mg3Ga2GeO8 Based on Energy Transfer from Cr3+ to Ni2+

Currently, near-infrared (NIR) light-emitting materials have been widely used in many fields, such as night vision, bioimaging, and nondestructive analysis. However, it is difficult to achieve multifunction in certain NIR light emitting phosphor. Herein, we propose a new near-infrared phosphor Mg₃Ga₂GeO₈:Cr³⁺,Ni²⁺ that can be applied to at least three fields, i.e., identification of compounds, temperature sensing, anticounterfeiting, and other applications. The multifunctional material exhibited efficient broadband emission of 650-1650 nm under 420 nm excitation. The emission intensity of Ni²⁺ in Mg₃Ga₂GeO₈:Cr³⁺,Ni²⁺ is enhanced by two times compared with that of Ni²⁺ in Mg₃Ga₂GeO₈:Ni²⁺ due to the energy transfer process. Compared with phosphor single doped with Ni²⁺, Mg₃Ga₂GeO₈:Cr³⁺,Ni²⁺ is more convincing in organic compound recognition because it is based on two emission bands: 600-1100 nm and 1100-1650 nm. As a temperature sensor, Mg₃Ga₂GeO₈:Cr³⁺,Ni²⁺ is an ideal temperature-sensing material. This work not only provides a super broadband NIR emitting phosphor with multiple functions but also presents a practical approach for the development of high-efficiency and multifunctional NIR phosphors.