Performance improvement by alumina coatings on YAlO:Ce phosphor powder deposited using atomic layer deposition in a fluidized bed reactor

To improve the thermal stability, Al 2 O 3 has been successfully coated on a Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) phosphor powder host by using the Atomic Layer Deposition (ALD) approach in a fluidized bed reactor. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray spectroscopy (EDX) analysis indicate that coating an Al 2 O 3 thin layer by ALD is highly feasible. The luminescence properties (such as excitation and emission as well as quantum efficiency and UV-absorption of the coated YAG:Ce phosphor) were systematically analysed, with the further examination of the thermal resistance characteristics. The Al 2 O 3 thin layer coating with precisely controlled thickness by ALD can obviously improve the luminescence intensity and greatly enhances the thermal stability of the YAG:Ce phosphor. It is suggested that the alumina coating with tailoring thickness seems not only to act like a barrier to decrease the thermal quenching, but also as a great help to promote the light absorption and transfer. To improve the thermal stability, Al 2 O 3 has been successfully coated on a Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) phosphor powder host by using the Atomic Layer Deposition (ALD) approach in a fluidized bed reactor.