Tuning Microstructure And Luminescence Of Nano-/microsized Single Host Phosphors For White Light

White LED (WLED) has become one of the key hi-technologies worldwide due to its attractive advantages of energy consumption saving, environmental and lifetime long-lasting aspects. However, the development of high luminous efficiency of WLED with low cost has been a bottleneck for future general solid illuminating purposes. A combination of high energy density Ultraviolet chip excited three-colour(RGB) multi-host phosphor is highly concerned to achieve satisfactory white. Of these, the single host phosphor with white-emitting is one of innovative and competitive approaches.To aim at the problems mentioned above, we investigated a new rare-earth doped single-host white emitting silicate phosphor. The relationships between preparation, microstructure and luminescent properties were investigated experimentally and theoretically in detail. The important results we obtained are described as follows:1) An aerosol process with starting material of composite sol was firstly employed to obtain phase-pure silicate base phosphor. The emission wavelengths lie at 437nm, 500nm and 606nm respectively upon excited by 375nm light. The loose phosphor particles in the size of around 4.45μm free of ball-milling were received to avoid lowering the luminance of phosphor without destroying its crystal lattice in traditional solid phase synthesis. The process offers a resource-saving, environmental and scalable competition capability.2) A series of process parameters such as seeded or unseeded with a nanoszied pseudoboehmite source, stochiometric control and peptizing procedure were examined experimentally in details to obtain a complete set of controllable .parameters of microstructure-luminescence relationships.3) The IIIB ions as microstructure modifier to the host were firstly found to have a strong disturbance of host microstructure, together with rare earth and transition ions, then lead to a effective tuning emission spectra closely related to the microstructure.4) By analyzing the space group of the host structure, we calculated and targeted the position of each atom in a crystal cell and the geometric locations of point luminescent centers were positioned. By identifying the Raman spectra of the phosphor, the location of Al ion was traced. Furthermore, by EPS analysis, the reasons why Al ion entering into the phosphor could tune the emission spectrum are proposed.5) The common and individual effects of Al and B modifiers added to the phosphor were analyzed further. Finally, we clarify the underlying mechanisms regarding to the three-colour emissions and colour tuning to produce white light upon adding these ions to the phosphor host.