Enhanced Mn2+ emission from cation disordered substitution in Ba6CaNaYAl2Si6O24:Eu2+, Mn2+ phosphors

Abstract

The emission of Mn2+ in an orange hue within cation-disordered optical materials, consisting of Ba6CaNaYAl2Si6O24:Eu-,(2+) Mn2+, was significantly enhanced through efficient energy transfer, when compared to the performance of Eu2+, Mn2+-doped Ba6Ca3Al2Si6O24 phosphors. The degree of polyhedral distortions within the Ba6CaNaYAl2Si6O24 structure was ascertained using synchrotron X-ray powder diffraction. The cation-disordered host structure incorporates 12-, 9-, and 10-coordinated polyhedra involving Ba(I), Ca/Y(II), and Ba/Na(III) ions, along with AlO6 octahedra and isolated SiO4 tetrahedra. Photoluminescence emission spectra of the cation-disordered Ba5.9-qEu0.1MnqCaNaYAl2Si6O24 (q = 0-0.4) phosphors were examined, along with the energy-transfer process from Eu2+ to Mn2+ according to F & ouml;rster's theory, both occurring under 365-nm excitation. White and orange electroluminescent emission spectra, color rendering index, correlated color temperature, Commission Internationale de l'Eclairage coordinates, and internal/external quantum efficiency were measured for Ba5.5Eu0.1Mn0.2CaNaYAl2Si6O24 phosphors, both with and without commercial phosphors on a 365-nm LED chip. Moreover, the activation energy of thermal quenching for Ba5.9-q-Eu0.1MnqCaNaYAl2Si6O24 (q = 0.2, 0.4) phosphors within the temperature range of 298-448 K was determined when illuminated by a 365-nm light-emitting diode (LED).