Metal鈥揙rganic Framework Luminescence in the Yellow Gap by Codoping of the Homoleptic Imidazolate 鈭?/sub>3[Ba(Im)2] with Divalent Europium

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• 作者：Jens-Christoph Rybak ; Michael Hailmann ; Philipp R. Matthes ; Alexander Zurawski ; J枚rn Nitsch ; Andreas Steffen ; Joachim G. Heck ; Claus Feldmann ; Stefan G枚tzend枚rfer ; J眉rgen Meinhardt ; Gerhard Sextl ; Holger Kohlmann ; Stefan J. Sedlmaier ; Wolfgang Schnick ; Klaus M眉ller-Buschbaum
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：May 8, 2013
• 年：2013
• 卷：135
• 期：18
• 页码：6896-6902
• 全文大小：462K
• 年卷期：v.135,no.18(May 8, 2013)
• ISSN：1520-5126

文摘

The rare case of a metal-triggered broad-band yellow emitter among inorganic鈥搊rganic hybrid materials was achieved by in situ codoping of the novel imidazolate metal鈥搊rganic framework _{鈭?/sub>³[Ba(Im)2] with divalent europium. The emission maximum of this dense framework is in the center of the yellow gap of primary light-emitting diode phosphors. Up to 20% Eu²⁺ can be added to replace Ba²⁺ as connectivity centers without causing observable phase segregation. High-resolution energy-dispersive X-ray spectroscopy showed that incorporation of even 30% Eu²⁺ is possible on an atomic level, with 2鈥?0% Eu²⁺ giving the peak quantum efficiency (QE = 0.32). The yellow emission can be triggered by two processes: direct excitation of Eu²⁺ and an antenna effect of the imidazolate linkers. The emission is fully europium-centered, involving 5d 鈫?/b> 4f transitions, and depends on the imidazolate surroundings of the metal ions. The framework can be obtained by a solvent-free in situ approach starting from barium metal, europium metal, and a melt of imidazole in a redox reaction. Better homogeneity for the distribution of the luminescence centers was achieved by utilizing the hydrides BaH2 and EuH2 instead of the metals.}