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

在Ce^&lt；3+&gt；和Tb^&lt；3+&gt；的d-f相变过程中，通过Ce^&lt；3+&gt；到Tb^&lt；3+&gt；的能量转移，化学和热稳定的LaPO_4显示出与Tb^&lt；3+&gt；的f-f跃迁相对应的绿色发射。讨论了透明LaPO4：Ce，Tb胶体溶液的溶剂和表面改性剂对其晶场和光致发光性能的影响。以醋酸酯和磷酸三甲酯为原料，在水和甲醇的混合溶剂中，经150℃以下高压处理，然后透析，制得透明的LaPO4：Ce，Tb胶体溶液。根据透射电子显微镜观察和动态光散射法测量的颗粒大小，颗粒的直径均小于10 nm。通过对LaPO4：Ce，Tb进行表面修饰，如添加聚磷酸钠、十二烷基磷酸酯和亲水性磷酸盐改性剂，或将修饰后的纳米颗粒在正己烷和二甲基亚砜中重新分散，制备出透明的LaPO4：Ce，Tb胶体溶液。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，即通过表面修饰来封顶表面阴离子空位。另一方面，我们尝试了用~5 nm的ZnS：Mn纳米粒子的胶体溶液来制备纳米粒子分散的树脂片。我们还研究了其他具有不同发光颜色和相同激发区域的荧光粉。

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.