The Microstructure And Spectra Of A Phosphor With Wider Excitation Bands For White LEDs

White LEDs (WLEDs) has become one of the key hi-technology world Wide due to its attractive advantages of energy consumption saving, environmental and lifetime long-lasting aspects. The YAG:Ce³⁺ phosphor puimped with chip blue light needs innovation to improve the properties. Of these, the silicate host phosphors with UV, nUV or blue-UV lights in wider excitation wavelength range for white-emitting is one of the innovative and competitive approaches.With the aim to the problems mentioned above, we investigated a new rare earth doped silicate base phosphor. The relationship between preparation, microstructure and luminescent properties presented experimentally and theoretically in detail. The important results we obtained are described as follows:A. A spray-pyrolysis procedure was employed to prepare phase-pure rare-earth doped silicate base phosphors. The measured wavelengths of these phosphors range from 350nm to 470nm. The typical emission wavelength lies at 567nm upon exited by 470nm light.B. The relationships between microstructure and luminescent properties of these silicate base phosphors are primarily obtained. The lower energy edge location of Eu²⁺ ion is found to correspond to a six-coordinated number by using Uiteret formula. Furthermore, the XRD ptterns, morphologies and spectra of Sr_xCa_2-xSiO₄,Sr_xMg_2-xSiO₄ and Sr_xBa_2-xSiO₄ phosphors were also characterized.C. A series of process parameters involved in spray-pyrolysis procedure, such as composition, sintering temperature were experimentally investigated.D. The as-received phosphor particles is self-assembled, loose, submicron sized,ball-mill free powders, resulting in improving the luminescent properties.E.We evaluate the stability of these phosphors, that is, chemical stability and thermal stability respectively.F. This process offers a resource saving, environmental-friendly and scalable competition capability to prepare the phosphors.