Preparation and luminescent properties research of fluoride phosphor K2NaInF6: Cr3+, Mn4+

Abstract

A series of K2NaIn1-x-yF6 phosphors doped with x% Cr3+ and y% Mn4+ were synthesized using hydrothermal synthesis. The properties of K2NaInF6: Cr3+, Mn4+ phosphors were analyzed by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra, and other tests. The energy transfer efficiency between Cr3+ and Mn4+ is 55 % at an excitation wavelength of 470 nm. The optimal doping concentrations of Cr3+ and Mn4+ were 10 mol% and 2 mol%, respectively. The photoluminescence luminescence quantum efficiency of K2NaIn0·88F6: 0.1Cr3+, 0.02Mn4+ phosphor is 36.8 %. The concentration quenching mechanism of single-doped Cr3+ and Mn4+ is dipole-dipole interaction in K2NaInF6 phosphor. However, in the case of Cr3+-Mn4+ co-doping, the mechanism is quadrupole-quadrupole interaction. The thermal stability of the K2NaIn0·88F6: 0.1Cr3+, 0.02Mn4+ sample was examined, revealing that the luminescence intensity at 423 K remained at 75.53 % of that at 303 K. The activation energy was determined to be 0.28 eV, indicating that the sample has excellent thermal quenching property. The realization of red-light emission, from visible to near-infrared wavelengths, can be achieved through the interaction between Cr3+ and Mn4+. Red light of different wavelengths can better regulate the excellent environment required for plant growth, which is expected to be applied to plant growth.