State Key Laboratory of Optoelectronic Materials and Technologies, Ministry of Education Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, PR China.
J Phys Chem A. 2009 Nov 19;113(46):12885-90. doi: 10.1021/jp908416q.
A series of carbazole-based beta-diketone derivatives and their europium(III) ternary complexes Eu(N-Cx)(3)phen were designed and synthesized, where N-Cx denotes carbazole-based beta-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 degrees 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 beta-diketonate ligands in the complexes are higher than that of the lowest excited level of Eu(3+) ion, (5)D(0), 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.
设计并合成了一系列基于咔唑的β-二酮衍生物及其铕（III）三元配合物 Eu(N-Cx)(3)phen，其中 N-Cx 表示咔唑环上 N 位带有不同烷基取代基的基于咔唑的β-二酮，phen 是 1,10-邻菲啰啉。热重分析（TGA）表明配合物的分解温度超过 360°C。测量了紫外-可见吸收光谱、光致发光（PL）和 Eu(III)配合物的荧光量子产率，并对其进行了比较，详细讨论了咔唑环上 N 位不同取代烷基对光致发光的影响，表明当取代烷基的结构发生变化时，配合物的吸收能力和能量转移效率之间存在竞争。配合物中β-二酮配体的三重态能级高于 Eu(3+)离子的最低激发能级（5）D(0)，因此 Eu(III)配合物的光致发光机制被提出为配体敏化发光过程。通过将配合物预先涂覆在 395nm 发射的 InGaN 芯片上，制备了红色 LED。所有结果表明，该系列 Eu(III)配合物是制造基于近紫外光的白色 LED 的红色组件的有前途的候选物。
