Beta-sialon phosphor deposits fabricated by electrophoretic deposition (EPD) process in a magnetic field

Phosphor deposits of β-sialon:Eu2+ were prepared by electrophoretic deposition (EPD) process within a magnetic field. Under the action of the magnetic force, which was parallel to the direction of the electric field of the EPD, the β-sialon:Eu2+ crystals were aligned along the c-axis of the hexagonal cell unit to form an oriented deposit via the EPD fabrication. Higher orientation degree was obtained at longer depositing time (300 s) and stronger applied magnetic field (12 T). The oriented deposit aligned along the c-axis obtained higher relative deposit density than the randomly fabricated deposit. Due to the improved relative density, the oriented deposit prepared within the magnetic field possessed an enhanced external quantum efficiency (ηex). Also, because of different relative densities of the deposits prepared within and without the magnetic field, they presented different chromaticity coordinates.