固相反应法制备BaHfO_3:Ce纳米粒子及发光特性

Preparation and Luminescence Characteristics of BaHfO_3∶Ce Nanoparticles by the Process of Solid-State Reaction

通过固相反应法合成了BaHfO3:Ce纳米粒子。采用XRD、SEM等手段分析了粉体合成过程的物相变化及形貌特性;用荧光光度计分析了样品的激发和发射光谱。结果表明:混合粉体经1000℃煅烧2h,合成出近似球形、分散性良好的BaHfO3:Ce纳米粒子,一次粒径约30nm。掺杂少量Ce3+离子能引起基质BaHfO3的晶格畸变,并未改变立方晶系结构。BaHfO3∶Ce样品的激发光谱由2个激发峰构成,峰值分别位于396和446nm处。396nm波长激发的发射光谱主要由2个发光谱带组成,其峰值分别位于531和591nm波长处,发光机制对应Ce3+的5d→2F5/2和5d→2F7/2能级跃迁。用446nm波长激发时,只有一个宽带发射峰,峰值位于593nm处,而530nm附近的峰已趋于平缓。当掺杂Ce3+的物质的量分数为0.9%时,发射峰值达到最大;当Ce3+含量为1.1%时,导致发射峰值强度降低,这是由于Ce3+的浓度猝灭产生的。

BaHfO3：Ce nanoparticles were synthesized by the process of solid-state reaction. Both XRD and SEM were adopted to analyze the phase change and the characteristics of BaHfO3：Ce nano-powders during calcining process. Excitation and emission spectra were analyzed separately with the fluorescence photometer. The result shows that the average diameter of the BaHfO3：Ce nano-powders being approximate to spherical morphology is about 30 nm and the powders have good dispersibility after calcining at 1 000 % for 2 h. It also shows that there is no change happened on the cubic crystal structure even though a little amount of Ce^3＋ ion added to the powders can lead to the lattice distortion of BaHfO3 matrix material. The excitation spectrum of BaHfO3： Ce nanoparticles has two excitation peaks separately at 396 nm and 446 nm points. The emission spectrum excited by the 396 nm light consists of two emission bands, peaking at 531 nm and 591 nm, respectively, the emission character of which changes from the 5d→^2F5/2 to5d→^2F7/2 transitions of Ce^3＋ cation. When the emission spectrum is excited by the 446 nm light, only one wide emission peak at 591 nm point exists and the other one at around 531 nm becomes fiat. When the Ce^3＋ dopant content is 0.9%（molar fraction）, the figure of the emission peak reaches its highest point. This figure, however, drops when the Ce^3＋ dopant content is 1.1%（ molar fraction）, which is resulted from the concentration quenching.