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Synthesis and characterization of (electro)luminescent materials based on charged [Eu3+/Organic chelate]- complexes within layered double hydroxide (Hydrotalcite) as host matrix

Sumeet Kumar ,  Marco Milanesio ,  Leonardo Marchese 

Università degli Studi del Piemonte Orientale (DISTA), Via V. Bellini 25/G., Alessandria 15100, Italy

Abstract

Charged anionic complexes of europium with various organic chelates have been synthesized and studied for its luminescent and further electroluminescent properties with LDH (Hydrotalcite) as host material. Synthesizing host-guest structure is a promising method to enhance charge transfer to the light emitting ion/ligands and also increase efficiency/life time of a device. The complexes and LDH are characterised by techniques (XRPD/FT-RAMAN/FT-IR/TGA/UV-Vis). Topas software is used for the analysis of the powder diffraction data. Diffraction peak shifting and peak broadening effects are realised on comparing the diffraction pattern before and after intercalation of europium complexes into the LDH.

Zn/Al LDH synthesized at a controlled pH of 5.5 - 6 and with general formula: [Zn1-xIIAlxIII(OH)2]x+[Ax/m m-.nH2O]x-
where (A= nitrate, and x=0.35) has been experimentally found to be more yielding and easy to get intercalated, with NO3- ions being replaced by separately synthesized europium complexes, among which [europium(III)+EDTA] in a basic environment (pH=8±0.5) was  difficult to intercalate into the LDH layers while experiments with the carbonate form showed no intercalation but separate phases of LDH and [europium+EDTA] complex on XRPD analysis. Tris(benzoylacetonato) mono(phenanthroline)europium(III) obtained from sigma aldrich and used without further purification is oxidised by pottasium permanganate in solution phase and the filtered sample after thorough washing with enough CO2 free water is dissolved into decarbonized water with molar ratio of 0.5 w.r.t M(III) part of LDH, the Solution obtained is put at 100 °C for 24 hrs and filtered/washed with further drying at 60 °C for 5 hours. Similar synthesis method is applied for obtaining coumarine-3-carboxylate chelated Eu(III) complexes.

 

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Related papers

Presentation: Poster at 11th European Powder Diffraction Conference, Poster session, by Sumeet Kumar
See On-line Journal of 11th European Powder Diffraction Conference

Submitted: 2008-04-30 21:01
Revised:   2009-06-07 00:48