Preparation and Characterization of Phosphors for LED

Preparation and Characterization of Phosphors for LED
　　Green lighting style was put forward at the background of global wanning and energy saving. White LED (light-emitting diode) is recognized as the green lighting product and will substitute the traditional bulbs. In present, the way employing an InGaN/GaN LED chip coated by YAG (yttrium aluminum garnet, Y3Al5O12) yellow phosphors is the main way to get w-LED. As a result, YAG yellow phosphor becomes critical for green lighting. In this paper, the YAG: Ce3+ phosphors were synthesized by traditional solid-state reaction, and the possible ingredients which Cylinder neodymium magnet may affect the luminescence property were investigated in detail.Ingredients including sintering temperature, Ce3+ concentration, as well as the doping of Ga3+, and Gd3+ are investigated in detail, in order to make the property of the experimental product consistent with the application.Using solid-state reaction method synthesized the YAG: Ce3+ yellow phosphor powders at 1500℃with the assistance of flux. The samples were characterized by XRD, SEM and fluorescence spectrometer. The classic absorption and emission of Ce3+ are cleanly observed, and the luminescence principle of Ce3+ in the host of YAG was testified.Microwave assisted synthesis together with heat-treatment at a high temperature are employed to prepare the phosphor of terbium-aluminium garnet co-doped by Ce3+ and Eu3+ (TAG: Ce, Eu). The particles of the prepared samples are clear and smooth. Most particles http://www.chinamagnets.biz have the size of less than 2 urn. The powder has slightly agglomeration. The classic absorption and emission of TAG: Ce, Eu are cleanly observed. Compared with the traditional high-temperature solid-state synthesis, this route employed in this investigation has the advantages of easier synthesizing, energy saving and environmental protecting. The time of heat-treatment should be 2-3 h. The reaction pathway has been analyzed, implying that the diffusion coefficient of aluminum is bigger than that of terbium, in Tb2O3—Al2O3 system.