Investigation of 5d0 → 7f4 Strong Emission in Caeuga3o7 and Application of Led in Plant Growth

Abstract

This paper aims to explore new phosphor materials with strong 5D0 → 7F4 peaks and apply them to plant growth LEDs. In this paper, a series of new CaEuGa3O7 phosphors doped with Bi, Ge, and Tb were synthesized by traditional high-temperature solid-phase method, XRD pattern and the structure, optical properties and application of the phosphors were studied. Under the irradiation of 365 nm ultraviolet light, the sample shows a deep red light. Photoluminescence spectra shows that CaEuGa3O7 has the strongest peak of 5D0 → 7F4, indicating its potential application in plant growth LEDs. In addition, doping with different concentrations of Bi, Ge, and Tb reduced the overall intensity of the matrix, but in the spectrum of Bi doping, it was found that the emission intensity ratio of 5D0 → 7F4 to 5D0 → 7F2 was increased, even higher than that of the matrix, and the charge transfer band was red-shifted. In order to determine the occupancy of the doped ions in the matrix, a simple POST (Preferential Occupancy Site Theory) site occupancy theory was used to analyze the situation of the doped ions. When the bond atomization energy between the doped ions and the cations in the host lattice is closer, that is, when the bond atomization energy deviation is the smallest, the doped ions are more likely to occupy the sites of the cations. The matrix CIE chromaticity coordinates (0.6527, 0.3469) are located in the deep red region, indicating that it has the potential for application in the field of plant lighting LEDs.

Keywords: Eu3+, Photoluminescence, Optical Spectra