Ionic liquid as plasticizer for europium(iii)-doped luminescent poly(methyl methacrylate) films

Abstract

Flexible luminescent polymer films were obtained by doping europium(III) complexes in blends of poly(methyl methacrylate) (PMMA) and the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C 6 3 ], where nta is 2-naphthoyltrifluoroacetonate, tta is 2-thenoyltrifluoroacetonate, phen is 1,10-phenanthroline, dpa is 2,6-pyridinedicarboxylate (dipicolinate) and choline is the 2-hydroxyethyltrimethyl ammonium cation. Bright red photoluminescence was observed for all the films upon irradiation with ultraviolet radiation. The luminescent films have been investigated by high-resolution steady-state luminescence spectroscopy and by time-resolved measurements. The polymer films doped with b-diketonate complexes are characterized by a very intense 5 D 0 -7 F 2 transition (up to 15 times more intense than the 5 D 0 -7 F 1 ) transition, whereas a marked feature of the PMMA films doped with [choline] 3 [Eu(dpa) 3 ] is the long lifetime of the 5 D 0 excited state (1.8 ms).

Interpretation of europium(III) spectra

“…It is also possible to determine the absolute quantum yield measurement of the heat dissipation by non-radiative deactivation. Gudmundsen and coworkers determined the absolute quantum efficiency of the europium(III) 2-thenoyltrifluoroacetonate complex [Eu(tta) 3 ] in acetone by a calorimetric method [774]. By this technique the temperature rise of the samples due to non-radiative deactivation is measured.…”

“…These ligands can act as an antenna to absorb the excitation light and to transfer the excitation energy to the higher energy levels of the Eu 3+ ion, from which the emitting excited levels can be populated. The photoluminescence of europium(III) complexes has been studied in solutions [1,2], polymer matrices [3,4], sol-gel glasses [5,6], functionalized sol-gel glasses [7][8][9][10][11], ionogels [12,13], liquid crystals [14][15][16], encapsulated into inorganic hosts such as zeolites [17][18][19][20] and in metal-organic frameworks (MOFs) [21,22]. The design of europium(III)-containing inorganic-organic hybrid materials is a popular research field [23][24][25][26].…”

A new tetrakis β-diketone ligand for NIR emitting LnIII ions: luminescent doped PMMA films and flexible resins for advanced photonic applications

“…23,24 Thus, in the present work, we have doped the newly developed visible and NIR emitting complexes into this matrix to get highly transparent lms that can also be electrospun into resins consisting of uniform wires of diameter 300-400 nm. The optical properties of the newly synthesized complexes and hybrid materials are reported and discussed.…”

Applications of Ionic Liquids for the Development of Optical Chemical Sensors and Biosensors

“…80 The use of hydrophobic [HMIm]Tf2N as a plasticizer for Eu(III)-doped PMMA/IL bulk films significantly improved their flexibility and enhanced the solubility of fluorescent Eu(III) complexes in the polymer matrix. 107 Owing to a more homogeneous distribution of the fluorophores in the PMMA polymer, the fluorescence quenching caused by undissolved aggregates was reduced.…”

“…However, we can already predict their further expansion due to the development of the new gas target materials, π-conjugated silica ionogels, and Eu(III)-doped PMMA films for potential determination of CO2; 53,59,62 2,4-dinitrotoluene and 2,4,6-trinitrotoluene; 64 and biologically active organic and inorganic compounds, 107 respectively.…”