Kim Doory, Kim Han-Eol, Kim Chang-Hong
Department of Chemistry, Hanyang University, Seoul 04763, South Korea.
Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, South Korea.
ACS Omega. 2020 May 5;5(19):10909-10918. doi: 10.1021/acsomega.0c00620. eCollection 2020 May 19.
Rare-earth-doped oxide-based phosphors have attracted great interest as light-emitting materials for technical applications and fundamental research because of their high brightness, tunable emission wavelength, and low toxicity, as well as chemical and thermal stability. The recent development of rare-earth-doped nanostructured materials showed improved phosphorescence characteristics, including afterglow and lifetime. However, the development of highly efficient phosphors remains challenging in terms of brightness and long persistence. Herein, novel protocols were developed for improving phosphorescence characteristics based on the energy transfer effect by chemical mixing of spectrally different phosphors. This protocol is based on the simple mixing method of different phosphors, which is totally different from the conventional methods but provides much brighter persistent phosphorescence. Simple chemical mixing methods significantly improved the afterglow intensity and lifetime of green and blue phosphors regardless of mixed time when subjected to a high-temperature solid-state reaction. In particular, chemical mixing after a high-temperature solid-state reaction enhanced the phosphorescence intensity more effectively than did chemical mixing before the reaction. We achieved increased luminescence of the phosphor, which is 10 times greater than that of the control sample, from all of the chemical mixing methods, which resulted in more efficient energy transfer than previously reported studies. Chemical mixing of three spectrally different phosphors was also performed to achieve multistep energy transfer for the first time, exhibiting a much higher afterglow intensity (∼2 times) than that of single-step energy transfer. This study provides a novel and simple method for the production of bright and long-persistent phosphors and thus expands their application range.
稀土掺杂的氧化物基磷光体因其高亮度、可调节的发射波长、低毒性以及化学和热稳定性，作为技术应用和基础研究的发光材料引起了极大的关注。稀土掺杂纳米结构材料的最新发展显示出改进的磷光特性，包括余辉和寿命。然而，就亮度和长余辉而言，高效磷光体的开发仍然具有挑战性。在此，基于光谱不同的磷光体的化学混合所产生的能量转移效应，开发了用于改善磷光特性的新方案。该方案基于不同磷光体的简单混合方法，这与传统方法完全不同，但能提供更亮的持续磷光。简单的化学混合方法显著提高了绿色和蓝色磷光体的余辉强度和寿命，无论在高温固态反应中混合时间如何。特别是，高温固态反应后的化学混合比反应前的化学混合更有效地增强了磷光强度。我们通过所有化学混合方法实现了磷光体发光的增加，其比对照样品高10倍，这导致了比先前报道的研究更有效的能量转移。还首次进行了三种光谱不同的磷光体的化学混合以实现多步能量转移，其表现出比单步能量转移高得多的余辉强度（约2倍）。本研究提供了一种新颖且简单的方法来生产明亮且长余辉的磷光体，从而扩大了它们的应用范围。
