Effect of Different Alkyl Groups at the N-Position on the Luminescence of Carbazole-Based β-Diketonate Europium(III) Complexes

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• 作者：Pei He ; Huihui Wang ; Shenggui Liu ; Jianxin Shi ; Gang Wang ; Menglian Gong
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：November 19, 2009
• 年：2009
• 卷：113
• 期：46
• 页码：12885-12890
• 全文大小：194K
• 年卷期：v.113,no.46(November 19, 2009)
• ISSN：1520-5215

文摘

A series of carbazole-based β-diketone derivatives and their europium(III) ternary complexes Eu(N-Cx)₃phen were designed and synthesized, where N-Cx denotes carbazole-based β-diketonates with different alkyl substituents at N-position of the carbazole ring and phen is 1,10-phenethroline. Thermogravimetric analysis (TGA) shows that the decomposition temperature of the complexes is over 360 °C. UV−visible absorption spectroscopy, photoluminescence (PL), and the luminescence quantum yield of the Eu(III) complexes were measured and compared with each other, and the effect of different substituted-alkyls at N-position in the carbazole ring on the photoluminescence was discussed in details, indicating there exists a competition between the absorption capacity and the energy transfer efficiency for the complexes when the structure of the substituted-alkyls changes. The triplet state energy levels of the β-diketonate ligands in the complexes are higher than that of the lowest excited level of Eu³⁺ ion, ⁵D₀, so the photoluminescence mechanism of the Eu(III) complexes was proposed as a ligand-sensitized luminescence process. Red LEDs were fabricated by precoating the complexes onto 395 nm emitting InGaN chips. All the results show that this series of Eu(III) complexes is a promising candidate as a red component in fabrication of NUV-based white LEDs.