Synthesis and research on optical Properties of Cr3+ doping MgGa2O4 materials

Abstract

Far-red light-emitting diodes (LEDs) have attracted increasing attention due to their positive effects on plant growth. When plants are exposed to far-red light, phytochrome far-red (PFR) absorbs the radiation and is converted into phytochrome red (PR), thereby stimulating plant growth. In this study, a far-red-emitting MgGa₂O₄:Cr³⁺ phosphor was synthesised using a thermal diffusion method. X-ray diffraction (XRD) analysis confirmed that at a calcination temperature of 1400°C, the material forms a single phase with good crystalline quality. Field-emission scanning electron microscopy (FESEM) images showed that the material possesses relatively large grains, ranging from 1 to 3 μm in size. Photoluminescence excitation (PLE) spectra revealed strong visible-light absorption, with two prominent peaks at approximately 415 and 574 nm. When excited at 415 nm, the material exhibited intense red emission, peaking at 707 nm, corresponding to the ²E→⁴A₂ transition. Furthermore, an LED experiment using this material in combination with a 430 nm LED chip was successfully conducted. These findings indicate that Cr³⁺-doped MgGa₂O₄ is a promising candidate for far-red light-emitting LEDs in agricultural lighting applications.