| 초록 |
Sr2Si5N8 has emerged as a host for rare earth doped phosphor materials applied in light emitting diodes (LEDs), because Sr2Si5N8:Eu2+ shows orange-red emission with high quantum efficiency and low thermal quenching under excitation with blue light, thus makes it an encouraging red phosphor to improve the color rendering of white LEDs. Although researchers have tried various methods and some of them were successful, difficulty in synthesis still seems to be the main obstacle for the investigation of compounds containing nitrogen. Synthesis of them tends to depend on trial and errors, without systematic investigation on how the synthetic conditions such as temperature, pressure, and atmosphere should be controlled. This may be because the system is very complicated, which includes multiple gas components and related chemical reactions. In this study, we investigated phase equilibria of the Sr–Si–N–O system by a first-principle thermodynamic calculation method. Phase diagrams of the Sr–Si–N–O system were simulated at various conditions based on density functional theory (DFT) calculations, which showed excellent agreement with the experimental results. |
