Metal-organic framework luminescence in the yellow gap by codoping of the homoleptic imidazolate ∞(3)[Ba(Im)2] with divalent europium.
Metal-organic framework luminescence in the yellow gap by codoping of the homoleptic imidazolate ∞(3)[Ba(Im)2] with divalent europium.
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DOI：
10.1021/ja3121718
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发表时间：
2013-04
影响因子：
15
通讯作者：
Jens-Christoph Rybak;Michael Hailmann;P. Matthes;Alexander Zurawski;Jörn Nitsch;Andreas Steffen;Joachim Heck
中科院分区：
文献类型：
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作者：
Jens-Christoph Rybak;Michael Hailmann;P. Matthes;Alexander Zurawski;Jörn Nitsch;Andreas Steffen;Joachim Heck
在无机-有机杂化材料中罕见的金属触发宽带黄色发射器是通过与二价铕原位共掺杂新型咪唑盐金属-有机框架∞(3)[Ba(Im)2]实现的。该密集骨架的最大发射点位于初级发光二极管荧光粉黄色间隙的中心。可以添加高达20%的Eu2+来取代Ba2+作为连接中心，而不会引起可观察到的相偏析。高分辨率能量色散x射线光谱显示，即使在原子水平上掺入30%的Eu2+也是可能的，2-10%的Eu2+产生峰值量子效率（QE = 0.32）。黄色发射可以通过两个过程触发：Eu2+的直接激发和咪唑酸连接体的天线效应。发射完全以铕为中心，涉及5d→4f跃迁，并取决于金属离子的咪唑盐环境。该骨架可以通过无溶剂原位方法从金属钡、金属铕和咪唑熔体在氧化还原反应中得到。利用氢化物ba2和EuH2代替金属，使发光中心的分布均匀性更好。
The rare case of a metal-triggered broad-band yellow emitter among inorganic-organic hybrid materials was achieved by in situ codoping of the novel imidazolate metal-organic framework ∞(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 2-10% 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 → 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.