title: Layered rare-earth hydroxide and oxide nanoplates of the Y/Tb/Eu system: phase-controlled processing, structure characterization and color-tunable photoluminescence via selective excitation and efficient energy transfer.
abstract: Well-crystallized (Y0.97-xTb0.03Eux)2(OH)5NO3·nH2O (x= 0-0.03) layered rare-earth hydroxide (LRH) nanoflakes of a pure high-hydration phase have been produced by autoclaving from the nitrate/NH4OH reaction system under the optimized conditions of 100 °C and pH ∼7.0. The flakes were then converted into (Y0.97-xTb0.03Eux)2O3phosphor nanoplates with color-tunable photoluminescence. Detailed structural characterizations confirmed that LRH solid solutions contained NO3-anions intercalated between the layers. Characteristic Tb3+and Eu3+emissions were detected in the ternary LRHs by selectively exciting the two types of activators, and the energy transfer from Tb3+to Eu3+was observed. Annealing the LRHs at 1100 °C produced cubic-lattice (Y0.97-xTb0.03Eux)2O3solid-solution nanoplates with exposed 222 facets. Multicolor, intensity-adjustable luminescence was attained by varying the excitation wavelength from ∼249 nm (the charge transfer excitation band of Eu3+) to 278 nm (the 4f8-4f75d1transition of Tb3+). Unitizing the efficient Tb3+to Eu3+energy transfer, the emission color of (Y0.97-xTb0.03Eux)2O3was tuned from approximately green to yellowish-orange by varying the Eu3+/Tb3+ratio. At the optimal Eu3+content ofx= 0.01, the efficiency of energy transfer was ∼91% and the transfer mechanism was suggested to be electric multipole interactions. The phosphor nanoplates developed in this work may be incorporated in luminescent films and find various lighting and display applications.
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004, China; Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wu
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004, China; Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Ji-Guang
authors.initials: JG
authors.lastname: Li
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004, China.
authors.forename: Jinkai
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Sakka
keywords: 10.11; 20.03; 20.09; color-tunable luminescence; energy transfer; layered rare-earth hydroxide; solid solution