Enhanced narrow-band green-emission and thermal stability via the introduction of Mg2+ in ZnB2O4:Mn2+ phosphor

Abstract

A narrow-band green-emitting phosphor ZnB₂O₄:Mn²⁺, Mg²⁺ was prepared by solid-state reactions. X-ray diffraction (XRD) and the Rietveld structural refinements were performed. The results show that the introduction of Mg²⁺ may suppress the formation of an impurity phase. The micro-structure, photoluminescence (PL) and reflectance spectra, PL decay curves as well as thermal quenching behavior were investigated. The phosphors exhibit a broad absorption band from 200 to 510 nm, while the emission spectra show a narrow band centered at 538 nm with a full-width at half-maximum (FWHM) of about 34 nm. Furthermore, after the introduction of Mg²⁺, the luminescence intensity of phosphor ZnB₂O₄:0.07Mn²⁺, 0.10Mg²⁺ is significantly enhanced by about 2 times, and it presents a relatively low thermal quenching behavior. The corresponding mechanisms for performance improvement were investigated in detail and the ion-size compensation effect of Mg²⁺ to Mn²⁺ is proposed. Additionally, the high activation energy (0.202 eV) and ultra-high color purity (97%) were calculated. These results imply that the ZnB₂O₄:Mn²⁺, Mg²⁺ phosphor has broad application prospects in the field of advanced backlight display. Moreover, the introduction of Mg²⁺ may be useful as an effective strategy to enhance the luminescence properties and thermal stability of Mn²⁺ or even other element-doped phosphors.