Thermal Properties of Mn4+-Doped Complex Fluoride Phosphors

Red phosphors based upon Mn⁴⁺-doped complex fluorides are currently being implemented in a variety of LED display and lighting applications.  These phosphors can enable high CRI (for lighting) or high color gamut (for LCD backlit displays) without significant efficiency losses.  However, the properties of these phosphors can significantly differ based upon the specific phosphor host.  One example is in the temperature quenching of luminescence where T_0.5, the temperature where emission intensity reaches 50% of the room temperature value.  Different Mn⁴⁺-doped complex fluoride phosphors can have T_0.5 values that vary by more than 100^oC.  In many applications, these differences in thermal quenching can prevent the use of these materials In this presentation, we discuss the various properties of numerous Mn⁴⁺-doped complex fluoride phosphors as a function of temperature.  Correlations between composition, vibrational properties, and luminescence properties will be discussed and analyzed.  Finally, the presence (or absence) of thermal quenching as a function of Mn⁴⁺ concentration will also be presented.