Liu Feng, Ma En, Chen Daqin, Yu Yunlong, Wang Yuansheng
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Graduate School of Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
J Phys Chem B. 2006 Oct 26;110(42):20843-6. doi: 10.1021/jp063145m.
To develop NaYF(4) as bulk luminescence material, transparent glass ceramics containing Er(3+): NaYF(4) nanocrystals were fabricated for the first time, and the influences of heat-treatment temperature and Er(3+) doping level on their upconversion luminescence were investigated. With increasing heating temperature, the upconversion intensity enhanced accordingly, attributing to the incorporation of more Er(3+) into the grown NaYF(4). Notably, when the heating temperature reached 650 degrees C, the upconversion intensity augmented drastically due to the occurrence of phase transition from the cubic NaYF(4) to the hexagonal one. Interestingly, for the samples heat-treated at 620 degrees C, when the Er(3+) doping level was increased from 0.05 to 2.0 mol %, the upconversion emission was whole-range tunable from monochromatic green to approximately monochromatic red, which could be mainly attributed to the cross-relaxation between Er(3+) ions. The excellent optical properties and its convenient, low-cost synthesis of the present glass ceramic imply that it is an excellent substitution material for the unobtainable bulk NaYF(4) crystal, potentially applicable in many fields.
为了将NaYF₄开发为块状发光材料，首次制备了含有Er³⁺:NaYF₄纳米晶体的透明玻璃陶瓷，并研究了热处理温度和Er³⁺掺杂水平对其上转换发光的影响。随着加热温度的升高，上转换强度相应增强，这归因于更多的Er³⁺掺入生长的NaYF₄中。值得注意的是，当加热温度达到650℃时，由于从立方相NaYF₄到六方相的相变发生，上转换强度急剧增加。有趣的是，对于在620℃热处理的样品，当Er³⁺掺杂水平从0.05mol%增加到2.0mol%时，上转换发射从单色绿色到近似单色红色实现了全范围可调，这主要归因于Er³⁺离子之间的交叉弛豫。这种玻璃陶瓷优异的光学性能及其便捷、低成本的合成方法表明，它是难以获得的块状NaYF₄晶体的优异替代材料，具有在许多领域的潜在应用价值。
