Preparation of transparent nanocrystal phosphors and their application for wavelength conversion optical devices

在激发Ce <3+>的d-f跃迁过程中，从Ce <3+>到Tb^<3+>的能量转移，显示出与Tb^<3+>的f-f跃迁相对应的化学和热稳定的掺杂Ce^<3+>和Tb^<3+>的绿色发射。讨论了溶剂和表面改性剂对透明LaPO_4: Ce， Tb胶体溶液晶体场和光致发光性能的影响。以醋酸盐和磷酸三甲酯为原料，在水和甲醇的混合溶剂中，经150℃以下的高压蒸箱处理，透析制得透明的LaPO_4: Ce， Tb胶体溶液。通过透射电子显微镜观察和动态光散射测量颗粒大小，颗粒直径小于10nm。我们找到了用表面改性法制备透明的LaPO_4: Ce， Tb胶体溶液的方法，如加入聚磷酸钠、磷酸十二烷基和亲水性磷酸盐改性剂，或将改性的纳米颗粒再分散在正己烷和二甲亚砜中。基于光致发光内量子效率的定量分析和衰减曲线的测量，我们验证了表面钝化，即通过表面修饰覆盖表面阴离子空位。另一方面，我们尝试用~ 5nm ZnS: Mn纳米颗粒的胶体溶液制备纳米分散树脂片。我们还研究了与ZnS: Mn具有不同发光颜色和相同激发区的其他荧光粉。

Chemically and thermally stable LaPO_4 doped with Ce^<3+> and Tb^<3+> exhibits green emission corresponding to the f-f transition of Tb^<3+> through energy transfer from Ce^<3+> to Tb^<3+> during exciting the d-f transition of Ce^<3+>. We discuss the influence of solvents and surface modifiers of the transparent LaPO_4 : Ce, Tb colloidal solutions on their crystal fields and photoluminescence properties. The transparent LaPO_4 : Ce, Tb colloidal solution was prepared from acetates and trimethyl phosphate in the mixed solvent of water and methanol by autoclave treatment below 150℃, followed by dialysis. According to the observation by transmission electron microscope and the particle size measurement by dynamic light scattering, the particles were less than 10nm in diameter. We found out the method for preparing transparent colloidal solutions of LaPO_4 : Ce, Tb with surface modification, e.g., by the addition of sodium polyphosphate, lauryl phosphate and hydrophilic phosphate modifiers, or by redispersing modified nanoparticles in n-hexane and dimethyl sulfoxide. We verified surface passivation, i.e., capping surface anion vacancies by surface modification based on the quantitative analysis of photoluminescence internal quantum efficiency and the decay curve measurement. On the other hand, we attempted to produce nanoparticle-dispersed resin sheets from the colloidal solution of 〜5nm ZnS : Mn nanoparticles. We also investigated other phosphors with different luminescence colors and the same excitation region as that of ZnS : Mn.