Microwave Synthesis of Sr2Si5N8 and SrSi2N2O2 Phosphors and their Photoluminescent Properties

• Main Authors: Jia-JinLi, 李嘉晉
• Other Authors: Shyan-Lung Chung
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/18675100427203472879

碩士 === 國立成功大學 === 化學工程學系 === 102 === White light-emitting diodes are believed to become important research project due to its advantages such as low power consumption, high efficiency, long lifetime, and environment friendliness. Phosphors are photons conversion material and essential materials for the fabrication of the LED. Most of current oxide phosphors used for white LED has some problems such as low thermal stability and low efficiency. It is necessary to develop a phosphor material which has high luminescence intensity, thermal stability and can be excited by UV or blue light. The recent literatures indicated that oxynitride phosphor and nitride phosphor had these excellent advantages. However, the synthesis methods of commercial phosphor powder and literature all use high temperature, high pressure, long soaking time, and expensive equipment. Because of the high cost of production, the application of phosphor for LED is limited. Based on microwave method (MW) and the knowledge of oxynitride and nitride phosphor, previous research in our laboratory used Calsium, as alkaline-earth metal to produce phosphor. This thesis discusses the oxynitride phosphor and nitride phosphor using Strontium as alkaline earth metal by using MW method. Different crystalline product was found under different conditions, mainly contain Sr2Si5N8, that is produced in higher temperature(1500-1600℃), and SrSi2O2N2, that is produced in lower temperature(1250-1500℃). This thesis focuses on the effect under different temperature control, the amount of additives, and soaking time. The optimal condition SrSi2O2N2 product has compared to the commercial phosphor powder YAG and NTR-135, and the luminescence intensity is 189% and 104% respectively. The SrSi2O2N2 product have a broad emission peak at 534nm that observed upon 460nm excitation, and with changing content of additives can effectively enhance the luminescence intensity and change its emission wavelength into longer wavelength. This thesis also mention that Sr2Si5N8 host lattice synthesis condition and discuss the effect of different soaking time and reaction temperature. The Sr2Si5N8 products have a broad emission peak at 610nm that observed upon 460nm excitation.