Rapid, convenient and low-energy preparation of spherical rare earth doped YAG phosphors by a laser sintering method†
In order to overcome the disadvantages of uncontrollable particle size, slow speed and high energy consumption existing in traditional phosphor preparation methods, we successfully prepared YAG:Ce and YAG:Dy phosphors rapidly and conveniently by using a laser sintering method with low energy consumption. The influence of different laser powers (3–27 W), scanning rates (50–800 mm s−1), powder thicknesses (50–800 μm), doping concentrations (0.25–1%), and post-treatments on their phase purity, morphology and optics was investigated. Spherical YAG phosphors with controllable particle size could be obtained through selecting appropriate parameters, and their PL intensity was enhanced by 300% after annealing; the average particle size was decreased to 46 μm after reducing the powder thickness to 50 μm. These results suggest that the reaction temperature and preparation period are greatly reduced compared with the conventional solid-state reaction method. A luminous efficiency (LE) of 80 lm W−1 and color rendering index (CRI) of 76.4 can be reached for the fabricated WLED using YAG:Ce phosphor, demonstrating its great potential applications in WLEDs. Interestingly, it is found that YAG:Dy phosphors exhibit red, pink, orange-yellow and pale-yellow emission color under various excitation wavelengths, showing significant potential application in the fields of anti-counterfeiting and fluorescent labeling. In short, according to our research, the laser sintering method has been proved to have a great potential application in the field of phosphor preparation.