Synthesis and characterization of novel europium β‐diketonate organic complexes for solid‐state lighting

Abstract

Volatile Eu complexes, namely Eu(TTA)3Phen, Eu(x)Y(1-x)(TTA)3Phen; Eu(x)Tb(1-x)(TTA)3Phen; Eu, europium; Y, yttrium; Tb, Terbium; TTA, thenoyltrifluoroacetone; and Phen, 1,10 phenanthroline were synthesized by maintaining stichiometric ratio. Various characterization techniques such as X-ray diffraction (XRD), photoluminescence (PL) and thermo gravimetric analysis/differential thermal analysis (TGA/DTA) were carried out for the synthesized complexes. Diffractograms of all the synthesized complexes showed well-resolved peaks, which revealed that pure and doped organic Eu(3+) complexes were crystalline in nature. Of all the synthesized complexes, Eu0.5Tb0.5(TTA)3Phen showed maximum peak intensity, while the angle of maximum peak intensity for all complexes was almost the same with slightly different d-values. A prominent sharp red emission line was observed at 611 nm when excited with light at 370 nm. It was observed that the intensity of red emissions increased for doped europium complexes Eu(x)Y(1-x)(TTA)3Phen and Eu(x)Tb(1-x)(TTA)3Phen, when compared with Eu complexes. Emission intensity increased in the following order: Eu(TTA)3Phen > Eu0.5Tb0.5(TTA)3Phen > Eu0.4Tb0.6(TTA)3Phen > Eu0.5Y0.5(TTA)3Phen > Eu0.4Y0.6(TTA)3Phen, proving their potential application in organic light-emitting diodes (OLEDs). TGA showed that Eu complexes doped in Y(3+) and Tb(3+) have better thermal stability than pure Eu complex. DTA analysis showed that the melting temperature of Eu(TTA)3Phen was lower than doped Eu complexes. These measurements infer that all complexes were highly stable and could be used as emissive materials for the fabrication of OLEDs.

Synthesis, characterization and properties of 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole derivatives and their europium complexes

“…The europium ion was determined by ethylenediaminetetraacetic acid (EDTA) titration using xylenol orange as an indicator. The carbon, hydrogen, and nitrogen analyses were carried out using an Elementar Vario EL-III elemental analyzer, 1 H NMR spectra were measured on a Varian-400 NMR (400 MHz) spectrometer (both from Agilent Technologies Co., Ltd., Beijing, China), spectra were taken in CDCl 3 or DMSO-d 6 solution using tetramethylsilane (TMS) as an internal reference. IR spectra in the 4000-400 cm À1 region were measured using KBr pellets on a PerkinElmer spectrometer (PerkinElmer Chengdu, Chengdu, China).…”

“…White crystals, yield 67%. 1 Synthetic methods of compounds L 1-8 were similar with each other, we took the synthetic method of the compound L 1 for example. A mixture of obtained compound 2 (2 mmol, 0.61 g), phenoxyacetic acid (6 mmol, 0.91 g) and phosphorus oxychloride (15 mL) were added to a 25 mL single-necked flask, then the reaction mixture was heated to 106°C and refluxed for 7 h. The solvent was removed under vacuum distillation and cooled at room temperature.…”

“…Rare earth organic complexes often show good optical properties, mainly due to their large stockes shifts, narrow emission bandwidths and long luminescence lifetimes [1,2], and they have been widely used in biomedical and functional materials [3], such as lasers materials [4], analytical and structure probe [5,6], and light emitting diodes [7,8]. The efficiency of ligand absorption in the UV region, ligand-to-metal energy transfer and rare earth luminescence play an important role in determining luminescence intensity [9].…”

“…This work might provide a reference for the development of the luminescent materials. The synthetic route of the 2,6-bis(4-(4-substituted phenoxymethyl)-1,2,4-triazolo [3,4-b] [1,3,4]thiadiazole)-pyridine derivatives is depicted in Scheme 1.…”

“…The 1,2,4-triazolo [3,4-b] [1,3,4]thiadiazole ring systems have been extensively studied due to their properties with respect to versatile biological activities including antibacterial, antifungal, anticancer, antitubercular and analgesic activities and other potential applications [10,11]. However, 1,2,4-triazolo- [3,4-b] [1,3,4]thiadiazoles have been seldom reported in literature with their corresponding rare earth ions complexes due to their poor solubility, not to mention the luminescence properties of their rare earth complexes. On the other hand, the triazole-thiadiazole compounds possess good conjugated plane, rigid structure and various coordination sites, are theoretically suitably used as the organic ligand of the rare earth luminescent complexes.…”