Synthesis And Properties Of YAG: Ce～(3+) Phosphor

White light-emitting diode(LED) is commonly considered as the leading and valuable light source in the 21st century owing to its excellent advantages over others. So it has attracted much attention and becomes one of the objects many researchers are seeking.Most commercial White LED is in the manner of light conversion, which is fabricated by coating YAG phosphors on the chip of blue LED. The YAG phosphors emit yellow light excited by the bule light and the two lights mix into white light. In this thesis, the synthesis and properties of YAG: Ce³⁺ phosphor is studied.Compared the methods of synthesizing phosphors, the YAG:Ce³⁺ phosphor is synthesized by sol-gel method. It is known that the structure of the phosphor is garnet after analyzing the XRD pattern of it. The crystal structure is firmed by higher temperature. The excitation spectra of YAG: Ce³⁺ phosphor have two peaks. The major one is around 460nm attributed to the 4f-5d transitions. Its emission band is wide with the peak at 530nm and it blongs to yellow-green light. Ce³⁺ acts as the activation in the phosphor, it effects the luminescent properties of YAG: Ce³⁺ phosphor. In this thesis, the best concentration of Ce³⁺ is made certain by comparing the emission spectra intensity of YAG phosphor with different Ce³⁺ concentration. Gd³⁺ doped YAG:Ce³⁺ phosphor is synthesized to cooperate with different wavelength of blue LED. It is analyzed that the structure of it is also garnet. The crystal parameter is changed correspond to the concentration of Gd³⁺. The excitation spectra has a peak at 460nm, and the emission spectra peak are between 540 to 560nm. The emission spectra peaks move to long wavelength according to the increase of concentration of Gd³⁺.