The Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Sciences and Engineering , University of Science and Technology Beijing , Beijing 100083 , P. R. China.
Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , China.
ACS Appl Mater Interfaces. 2018 Jul 25;10(29):24648-24655. doi: 10.1021/acsami.8b08129. Epub 2018 Jul 13.
Topological chemical reaction methods are indispensable for fabricating new materials or optimizing their functional properties, which is particularly important for two-dimensional (2D)-layered compounds with versatile structures. Herein, we demonstrate a low-temperature (∼350 °C) ion exchange approach to prefabricate metastable phosphors ALaTaO: xBi (A = K and Na) with RbLaTaO: xBi serving as precursors. The as-prepared ALaTaO:0.02 Bi (A = Rb, K, and Na) share the same Dion-Jacobson type 2D-layered perovskite phase, and photoluminescence analyses show that ALaTaO:0.02 Bi (A = Rb, K, and Na) phosphors exhibit broad emission bands peaking at 540, 550, and 510 nm, respectively, which are attributed to the nonradiative transition of Bi from excited state P or P to ground state S. The various Bi local environments at the crystallographic sites enable the different distributions of emission and excitation spectra, and the photoluminescence tuning of ALaTaO:0.02 Bi (A = Rb, K, and Na) phosphors are realized through alkali metal ion exchange. Notably, the combination of superior trivalent bismuth emission and low-temperature ion exchange synthesis leads to a novel yellow-emitting K(LaBi)TaO phosphor which is successfully applied in a white LED device based on a commercially available 365 nm LED chip. Our realizable cases of this low-temperature ion exchange strategy could promote exploration into metastable phosphors with intriguing properties.
拓扑化学反应方法对于制造新材料或优化其功能特性是必不可少的，这对于具有多种结构的二维（2D）层状化合物尤为重要。在此，我们展示了一种低温（~350°C）离子交换方法，用于预制亚稳荧光粉 ALaTaO:xBi（A=K 和 Na），其中 RbLaTaO:xBi 用作前驱体。所制备的 ALaTaO:0.02Bi（A=Rb、K 和 Na）具有相同的 Dion-Jacobson 型二维层状钙钛矿相，光致发光分析表明 ALaTaO:0.02Bi（A=Rb、K 和 Na）荧光粉分别表现出 540、550 和 510nm 处的宽发射带，归因于 Bi 从激发态 P 或 P 到基态 S 的非辐射跃迁。晶体位置中不同的 Bi 局部环境使发射和激发光谱的分布不同，通过碱金属离子交换实现了 ALaTaO:0.02Bi（A=Rb、K 和 Na）荧光粉的光致发光调谐。值得注意的是，三价铋发射的优越性和低温离子交换合成的结合导致了一种新型的黄色发射 K(LaBi)TaO 荧光粉，该荧光粉成功应用于基于市售 365nm LED 芯片的白色 LED 器件中。我们这种低温离子交换策略的可实现案例可以促进对具有有趣性质的亚稳荧光粉的探索。
