Ilmi Rashid, Khan Muhammad S, Li Zhenzhen, Zhou Liang, Wong Wai-Yeung, Marken Frank, Raithby Paul R
Department of Chemistry , Sultan Qaboos University , P.O. Box 36, Al Khod 123 , Sultanate of Oman.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Renmin Street 5625 , Changchun 130022 , People's Republic of China.
Inorg Chem. 2019 Jul 1;58(13):8316-8331. doi: 10.1021/acs.inorgchem.9b00303. Epub 2019 Jun 13.
Two new lanthanide complexes [Ln(hfaa)(Py-Im)] [hfaa = hexafluoroacetylacetone, Py-Im = 2-(2-pyridyl)benzimidazole and Ln = Eu(III) (1) and Tb(III) (2)] were synthesized and characterized. An X-ray crystal structure determination confirms that complex 1 is eight-coordinate with a distorted trigonal dodecahedral geometry. It shows typical vivid red Eu(III) emission in the solid state, in solution, and in a polymer matrix. The observed lifetime (τ) of complex 1 in the solid state, in dichloromethane (DCM) solution, and in thin films is 833.01, 837.95, and 626.16-715.69 μs, respectively, with a photoluminescence quantum yield Q ≈ 33% in DCM solution. Complex 2 displays a yellowish-green emission in the solid state (τ ≈ 36.99 μs), while a near white-light emission in solution (x; 0.2574: y; 0.3371) and in thin films. Therefore, it is a potential candidate for generating single-component white light-emitting materials for solid-state lighting applications. The kinetic scheme for modeling energy-transfer processes shows that the main donor state for 1 is the ligand triplet state (T) and that energy transfer occurs to both the D (56.55%) and D (40.58%) levels. We fabricated a series of single- and double-layer organic light-emitting devices using complex 1. The luminance of the optimized double-layer electroluminescence (EL) device was 373 cd/m with very low turn-on voltage of ∼4.2 V. Complex 1 was further utilized as a sensitizer to improve the EL of a red-emitting iridium complex PQIr(dpm) (PQ = phenylquinoly-N,C2', dpm = dipivaloylmethane). The codoped device achieved a maximum brightness and maximum current efficiency (η) of 93 224 cd/m and 36.38 cd/A, respectively.
合成并表征了两种新型镧系配合物[Ln(hfaa)(Py-Im)] [hfaa = 六氟乙酰丙酮，Py-Im = 2-(2-吡啶基)苯并咪唑，Ln = Eu(III) (1) 和Tb(III) (2)]。X射线晶体结构测定证实配合物1为八配位，具有扭曲的三角十二面体几何构型。它在固态、溶液和聚合物基质中均表现出典型的鲜艳红色Eu(III) 发射。配合物1在固态、二氯甲烷（DCM）溶液和薄膜中的观测寿命（τ）分别为833.01、837.95和626.16 - 715.69 μs，在DCM溶液中的光致发光量子产率Q ≈ 33%。配合物2在固态中呈现黄绿色发射（τ ≈ 36.99 μs），而在溶液（x; 0.2574: y; 0.3371）和薄膜中呈现近白光发射。因此，它是用于固态照明应用的单组分白色发光材料的潜在候选物。用于模拟能量转移过程的动力学方案表明，1的主要供体状态是配体三重态（T），并且能量转移到D（56.55%）和D（40.58%）能级。我们使用配合物1制备了一系列单层和双层有机发光器件。优化后的双层电致发光（EL）器件的亮度为373 cd/m²，开启电压非常低，约为4.2 V。配合物1还被用作敏化剂以改善红色发光铱配合物PQIr(dpm)（PQ = 苯基喹啉-N,C2'，dpm = 二戊酰甲烷）的电致发光。共掺杂器件分别实现了93 224 cd/m²的最大亮度和36.38 cd/A的最大电流效率（η）。
