Thermal management of KSF-converted white light-emitting diodes toward high light efficiency

Potassium hexafluorosilicate (K 2 SiF 6 :Mn 4+ , KSF) has been widely applied in phosphor-converted white light-emitting diodes (WLEDs) because of its exceptional luminescent efficiency and color performance. However, the device performance is strongly affected by temperature-dependent optical properties of KSF. Here, we studied the temperature-dependent PL dynamics of KSF and revealed the proper temperature range for optimizing light conversion efficiency. The impact of different packaging structures and heat-conductive fillers on the thermal characteristics of the KSF-LED devices was evaluated by experimental tests and simulations. The results indicate that a 5 wt% Al 2 O 3 particle filler, plus a KSF-LuAG dual-layer package configuration, provides the most significant cooling effect, achieving a >10 °C reduction in operating temperature and a 114% increase in light intensity under high LED power density. These findings offer valuable insights for improving the luminous efficiency of KSF-WLEDs.