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Eu 3+ ‐tetrakis β‐diketonate complexes for solid‐state lighting application
Author(s) -
Leite Silva Camila M.B.,
BispoJr Airton G.,
Canisares Felipe S.M.,
Castilho Shirley A.,
Lima Sergio A.M.,
Pires Ana M.
Publication year - 2019
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.3686
Subject(s) - solid state lighting , quantum efficiency , stoichiometry , molecule , chemistry , light emitting diode , tris , diode , thermal stability , emission intensity , analytical chemistry (journal) , photochemistry , materials science , luminescence , optoelectronics , organic chemistry , biochemistry
Abstract Eu 3+ –β‐diketonate complexes are used, for example, in solid‐state lighting (SSL) or light‐converting molecular devices. However, their low emission quantum efficiency due to water molecules coordinated to Eu 3+ and low photostability are still problems to be addressed. To overcome such challenges, we synthesized Eu 3+ tetrakis complexes based on [Q][Eu(tfaa) 4 ] and [Q][Eu(dbm) 4 ] (Q1 = C 26 H 56 N + , Q2 = C 19 H 42 N + , and Q3 = C 17 H 38 N + ), replacing the water molecules in the tris stoichiometry. The tetrakis β‐diketonates showed desirable thermal stability for SSL and, under excitation at 390 nm, they displayed the characteristic Eu 3+ emission in the red spectral region. The quantum efficiencies of the dbm complexes achieved values as high as 51%, while the tfaa complexes exhibited lower quantum efficiencies (28–33%), but which were superior to those reported for the tris complexes. The structures were evaluated using the Sparkle/PM7 model and comparing the theoretical and the experimental Judd–Ofelt parameters. [Q1][Eu(dbm) 4 ] was used to coat a near‐UV light‐emitting diode (LED), producing a red‐emitting LED prototype that featured the characteristic emission spectrum of [Q1][Eu(dbm) 4 ]. The emission intensity of this prototype decreased only 7% after 30 h, confirming its high photostability, which is a notable result considering Eu 3+ complexes, making it a potential candidate for SSL.