Maria Claudia França da Cunha Felinto
@ipen.br
Professor Dr / Comissão Nacional de Energia Nuclear
Instituto de Pesquisas Energéticas e Nucleares
Scopus Publications
Scopus Publications
Israel F. Costa, Lucca Blois, Tiago B. Paolini, Israel P. Assunção, Ercules E.S. Teotonio, Maria Claudia F.C. Felinto, Renaldo T. Moura Jr., Ricardo L. Longo, Wagner M. Faustino, Luís D. Carlos,et al.
Elsevier BV
Paulo R. S. Santos, Ashley A. S. S. Jesus, William B. Lima, Joaldo G. Arruda, Wagner M. Faustino, Maria C. F. C. Felinto, José R. Sabino, Hermi F. Brito, Israel F. Costa, Renaldo T. Moura,et al.
Wiley
AbstractA series of novel lanthanide β‐diketonate coordination compounds containing the ancillary ligand bis(diphenylphosphino) oxide (dppeO2) have been synthesized, characterized, and studied spectroscopically. The compounds of formulas Ln(β‐dik)3(dppeO2), where Ln: Eu and Gd and β‐dik ligands as tta (Ln‐1), btf (Ln‐2), bzac (Ln‐5) and tfac (Ln‐4), and Ln2(β‐dik)6(dppeO2) with ligand dbm (Ln‐3) and fod (Ln‐6). Their photophysical properties were investigated from the Judd‐Ofelt intensity parameters ( ), radiative ( ) and non‐radiative ( ) rates, intrinsic ( ) and overall ( ) quantum yields, and CIE (x,y) color coordinates. The Eu‐5 and Eu‐6 compounds have the first excited triplet states T1 (around 18802 and 18976 cm−1, respectively) almost resonant with the Eu3+ 5D0 emission level, whereas the complexes Eu‐1, Eu‐2, Eu‐3, and Eu‐4 exhibited higher T1 energies. The values were predominantly driven by the intensity parameter , suggesting more pronounced angular changes in the first coordination sphere of the Eu3+ ion. The values also exhibited significant changes with the β‐diketonate ligands. Eu‐1 showed the highest value of (60 %), indicating a more efficient intramolecular energy transfer process. On the other hand, Eu‐5 and Eu‐6 compounds showed values equal to 18.7 % and 16.5 %, respectively, which indicates the presence of luminescence quencher channels.
Tiago B. Paolini, Israel P. Assunção, Israel F. Costa, Lucca Blois, Maria Cláudia F.C. Felinto, Renaldo T. Moura Jr., Ercules E.S. Teotonio, Oscar L. Malta, Albano N. Carneiro Neto, and Hermi F. Brito
Elsevier BV
Renan P. Moreira, Leonardo H.C. Francisco, Israel F. Costa, Helliomar P. Barbosa, Ercules E.S. Teotonio, Maria C.F.C. Felinto, Oscar L. Malta, and Hermi F. Brito
Elsevier BV
Israel P. Assunção, Israel F. Costa, Paulo R. S. Santos, Ercules E. S. Teotonio, Maria Claudia F. C. Felinto, Ulrich Kynast, Wagner M. Faustino, Oscar Malta, and Hermi F. Brito
American Chemical Society (ACS)
Zahid Ullah Khan, Mayara Klimuk Uchiyama, Latif Ullah Khan, Koiti Araki, Hiro Goto, Maria Claudia França Cunha Felinto, Ana Olivia de Souza, Hermi Felinto de Brito, and Magnus Gidlund
Royal Society of Chemistry (RSC)
To develop fluorescent bionanoprobe for cellular imaging, it is crucial to get precise insight on the particle–cell interaction, optical properties of QDs in and out of the cell, their movement in and out of the cell, and the final fate of particle.
Leonardo H.C. Francisco, Renan P. Moreira, Maria C.F.C. Felinto, Veronica C. Teixeira, Hermi F. Brito, and Oscar L. Malta
Elsevier BV
Abstract Recently, several classes of rare-earth-doped luminescent materials have been drawing attention due to structurally engineered energy converting systems, capable of tuning absorption and emission spectral ranges, outlining new materials and applications in photonics. In this scenario, this work presents the development of SrAl2O4:Eu2+,Dy3+ phosphors prepared by the Pechini method, which were further APTMS-functionalized (3-aminopropyltrimethoxysilane) by microwave-assisted synthesis, incorporating a Eu3+ β-diketonate complex embedded within a SiO2-R network to increase light absorption and promote energy transfer processes. Powder X-ray diffraction data revealed a stable characteristic monoclinic phase of the SrAl2O4 host matrix, which undergoes structural changes after functionalization. Particle morphology and elemental distribution were probed by scanning electron microscopy technique, exhibiting surface alteration effects. Photoluminescence spectra displayed a characteristic broad green emission band assigned to the 4f65d1(2D) → 4f7(8S7/2) interconfigurational transition of the Eu2+ ion. Functionalized materials presented absorption shifts coupled with an emission band intensification suggesting effective interactions between the β-diketonate complex, the SiO2-R network, and the inorganic host matrix. Increased absorption range and persistence decay time under near band gap excitation on modified materials were also observed.
Renaldo T. Moura Jr., Albano N. Carneiro Neto, Eduardo C. Aguiar, Carlos V. Santos-Jr., Ewerton M. de Lima, Wagner M. Faustino, Ercules E.S. Teotonio, Hermi F. Brito, Maria C.F.C. Felinto, Rute A.S. Ferreira,et al.
Elsevier BV
José Miranda de Carvalho, Cássio Cardoso Santos Pedroso, Matheus Salgado de Nichile Saula, Maria Claudia França Cunha Felinto, and Hermi Felinto de Brito
MDPI AG
Luminescent inorganic materials are used in several technological applications such as light-emitting displays, white LEDs for illumination, bioimaging, and photodynamic therapy. Usually, inorganic phosphors (e.g., complex oxides, silicates) need high temperatures and, in some cases, specific atmospheres to be formed or to obtain a homogeneous composition. Low ionic diffusion and high melting points of the precursors lead to long processing times in these solid-state syntheses with a cost in energy consumption when conventional heating methods are applied. Microwave-assisted synthesis relies on selective, volumetric heating attributed to the electromagnetic radiation interaction with the matter. The microwave heating allows for rapid heating rates and small temperature gradients yielding homogeneous, well-formed materials swiftly. Luminescent inorganic materials can benefit significantly from the microwave-assisted synthesis for high homogeneity, diverse morphology, and rapid screening of different compositions. The rapid screening allows for fast material investigation, whereas the benefits of enhanced homogeneity include improvement in the optical properties such as quantum yields and storage capacity.
Bakhat Ali, Helio A. Stefani, Muhammad Imran, Ahmad Irfan, Mohammed A. Assiri, Maria Claudia F. C. Felinto, Muhammad Khalid, and Abdullah G. Al-Sehemi
Springer Science and Business Media LLC
The synthesis of 1-benzyl-2-((2-Aminoethyl) amino)-5-oxopyrrolidine-3,4-diyl diacetate (boad), an oxopyrrolidine type ligand; designed to coordinate lanthanides (Eu3+ and Tb3+) to get luminescent material. The target complexes showed good photoluminescence properties, which indicate that this type of compound can be used as sensitizers having luminescence for the green (Tb3+) and red (Eu3+) emission. The obtained results revealed that sensitizer efficiency can be improved by adding ligands like acac (Eu(acac)3, which has also enhanced the luminescence quantum output and period for Eu3+ ions. The ground state geometries were developed by using density functional theory at B3LYP/6-31G** level. The charge transfer analysis and electronic properties were performed. The Europium and Terbium complexes formation with boad ligand was explored based on molecular electrostatic potential, MDC-q charges, and frontier molecular orbitals (FMOs) analysis.
Israel F. Costa, Gilvan P. Pires, José Geraldo P. Espínola, Hermi F. Brito, Maria Claudia F.C. Felinto, Wagner M. Faustino, and Ercules E.S. Teotonio
Wiley
This paper reports on the preparation, characterization, and photoluminescence properties of novel hybrid materials, in which the EDTA-Ln-L complexes (where L: H2 O, acac, bzac, dbm, and tta ligands, and Ln: Eu, Gd, and Tb) were covalently linked to the precursor medium molecular weight chitosan surface (CS) matrices or on the chitosan surfaces previously crosslinked with epichlorohydrin (CSech). The emission spectra of these materials were characterized by intraconfigurational-4fN transitions centred on the Eu3+ and Tb3+ ions. Some broad bands from the polymeric matrix were also observed in the emission spectra, however the relative intensities of the intraconfigurational bands increased significantly for systems containing diketonate ligands when the antenna effect became more efficient. The values of the radiative rates (Arad ) were higher for crosslinked hybrid systems with epichlorohydrin, while nonradiative rates (Anrad ) presented the opposite behaviour. These data contributed to an increase in the values of emission quantum efficiency (η) for crosslinked materials. The effect of the modification process and antenna ligand on the values of intensities, intensity parameters Ω2 e Ω4 of the Eu3+ complexes were also investigated. The results showed that the crosslinked biopolymer surfaces have great potential for applications in molecular devices light converters.
Lucca B. Guimarães, Alexandre M. P. Botas, Maria C. F. C. Felinto, Rute A. S. Ferreira, Luis D. Carlos, Oscar L. Malta, and Hermi F. Brito
Royal Society of Chemistry (RSC)
Precise optical temperature sensors based on luminescent Tb3+:Eu3+ tetrakis complexes with imidazolic counterions with high emission quantum yield values and low temperature uncertainty.
Edson Gaiollo, Renan Moreira, Maria Felinto, Helliomar Barbosa, Cássio Pedroso, Ercules Teotonio, Oscar Malta, and Hermi Brito
Sociedade Brasileira de Quimica (SBQ)
L. H. C. Francisco, M. C. F. C. Felinto, H. F. Brito, E. E. S. Teotonio, and O. L. Malta
Springer Science and Business Media LLC
In this work, [Eu(tta)3(4-picNO)2] and [Eu(dbm)3(4-picNO)] complexes were incorporated on different concentrations (x = 1, 3, 5, 10 and 15%) in PMMA polymeric matrix (4-picNO: 4-Methylpyridine N-oxide) by the solvent casting method, yielding transparent and highly luminescent polymeric films. These materials were analyzed by X-ray diffraction, scanning electron microscopy and by energy dispersive, ultraviolet–visible spectroscopy, luminescence and vacuum ultraviolet–ultraviolet spectroscopies. The luminescence spectra of doped PMMA films are in agreement with an efficient intramolecular diketonate (tta) ligand-to-europium energy transfer. Furthermore, the values of experimental intensity parameters (Ω2,4) for luminescent polymeric materials were quite similar to those ones for isolated complexes, indicating that there is a homogeneous dispersion of Eu3+ complexes in the polymeric matrix, preserving their chemical and structural features. These behavior were also observed from the CIE diagram that show great similarity between the (x,y) coordinates for the doped PMMA samples compared to the isolated β-diketonate complexes with a reddish color tuning. The photostability investigation of the doped PMMA polymeric films and Eu3+ complexes has been also reported.
Israel P. Assunção, Albano N. Carneiro Neto, Renaldo T. Moura, Cássio C. S. Pedroso, Ivan G. N. Silva, Maria C. F. C. Felinto, Ercules E. S. Teotonio, Oscar L. Malta, and Hermi F. Brito
Wiley
The odd-even effect in luminescent [Eu₂(L)₃(H₂O)x]•y(H2O) complexes with aliphatic dicarboxylate ligands (L: OXA, MAL, SUC, GLU, ADP, PIM, SUB, AZL, SEB, UND, and DOD, where x = 2-6 and y = 0-4), prepared by the precipitation method, was observed for the first time in lanthanide compounds. The final dehydration temperatures of the Eu³+ complexes show a zigzag pattern as a function of the carbon chain size of the dicarboxylate ligands, leading to the so-called odd-even effect. The FTIR data confirmed the ligand-metal coordination via the mixed mode of bridge-chelate coordination, except for the Eu³+-oxalate complex. XRD results point out to highly crystalline materials belonging to the monoclinic system. The odd-even effect on the 4f-4f luminescence intensity parameters (Ω₂ and Ω₄) was explained by using an extension of the Dynamic Coupling mechanism, herein named the Ghost-Atom model. In this method, the long-range polarizabilities (α*) were simulated by a Ghost-Atom located at the middle of each ligand chain. The values of α* were estimated using the localized molecular orbital approach. The emission intrinsic quantum yield (Q_Ln^Ln) of the Eu³+ complexes also presented an the odd-even effect, successfully explained in terms of the zigzag behavior showed by the Ω₂ and Ω₄ intensity parameters. Luminescence quenching due to water molecules in the first coordination sphere was discussed and rationalized.
Haryane R.M. Silva, Wagner M. Faustino, Ercules E.S. Teotonio, Hermi F. Brito, Oscar L. Malta, and Maria Cláudia F.C. Felinto
Elsevier BV
Abstract Three new β-diketone–Ln-EDTA (β-diketone = TTA, BTFA, ACAC; Ln=Eu3+ and Tb3+) water-soluble complexes were prepared, and their photophysical properties were investigated in aqueous solutions and compared with the Eu–EDTA complex. A very strong red and green luminescence was observed by the addition of ligands to the aqueous solutions of the Eu–EDTA and Tb–EDTA complexes, respectively, due to the formation of water-soluble β-diketone–Ln–EDTA complexes. To confirm the formation and stoichiometry of the new β-diketone–Ln–EDTA complex, the Judd–Ofelt intensity parameters Ω2 for Eu3+ complexes and the band width at half height (Δλ) for Tb3+ complexes were used. The dependence of these parameters on the addition of the β-diketone strongly suggests that only one β-diketonate ligand is in the first coordination sphere of the β-diketone–Ln–EDTA complexes. These new Eu3+ and Tb3+ systems may act as red and green optical markers for bioassay or bioimaging.
Albano N. Carneiro Neto, Ercules E.S. Teotonio, Gilberto F. de Sá, Hermi F. Brito, Janina Legendziewicz, Luís D. Carlos, Maria Claudia F.C. Felinto, Paula Gawryszewska, Renaldo T. Moura, Ricardo L. Longo,et al.
Elsevier
Abstract A critical review on the mechanisms and behavior of 4f intraconfigurational transitions in controllable chemical environments related to nonradiative intramolecular energy transfer processes in lanthanide chelates is presented. The term “modeling” is here used in the sense of manipulating and controlling the photophysical properties of these compounds, allowing obtaining distinguished and specific luminescent behavior. In this chapter an effort is made to show that a theoretical model, jointly used with experimental available data, is able to provide this modeling process in a comprehensive and useful way. The model allows estimating quantitatively intramolecular energy transfer rates by several mechanisms. Selection rules and the spectral overlap factor (energy mismatch conditions, for which an analytical expression is available) may be used to define relevant energy transfer pathways, and the solution (analytically or numerically) of appropriate systems of rate equations is crucial to deduce dominant pathways. Emission quantum yields, then, can be estimated and rationalized. In these rate equations all possible transition channels (radiative and non-radiative) must be included; some of them may be taken into account through the level decaying lifetime. Attempts to standardize notation is made, and some misinterpretations, perspectives and challenges on this subject are discussed.
Israel Costa, Jandeilson Moura, Rian Aderne, Harold Avila, Marco Cremona, Hermi Brito, Maria Cláudia Felinto, Wagner Faustino, and Ercules Teotonio
Sociedade Brasileira de Quimica (SBQ)
In this study, a novel type of tris(2-acyl-1,3-indandione)-aluminum(III) coordination compounds of the general formula [Al(acind)3]H2O, where 2-acyl-1,3-indandione (acind), 2-acetyl1,3-indandione (aind), 2-benzoyl-1,3-indandione (bind), and 4-methyl-2-benzoyl-1,3-indandione (mbind), were synthesized and characterized by elemental analysis (CHN), Fourier transform infrared (FTIR) and nuclear magnetic resonance (H NMR) spectroscopies, thermal analysis (TG/DTG and DTA), and optical absorption spectroscopy in the UV-Vis region. These compounds present remarkably high green luminescence in powder and in thin-film forms. However, when these compounds are applied in glass/ITO/β-NPB/spiro-2CBP/[Al(acind)3]/Al and glass/ITO/β-NPB/ [Al(acind)3]/LiF/Al electroluminescent devices, where spiro-2CBP is 2,7-bis(carbazol-9-yl)-9,9spirobifluorene and β-NPB is N,N’-bis(naphthalen-2-yl)-N,N’-bis(phenyl)-benzidine, the emission color tuned from green to red, reflecting a change from the direct charge recombination in the emitting layer of the [Al(acind)3] complexes to an exciplex-based emission in which [Al(acind)3] complexes and spiro 2-CBP acted as acceptor and donor, respectively. These results suggest that [Al(acind)3] complexes have potential applications as molecular light converter materials for fabricating new electroluminescent devices.
Everton Bonturim, Leonnam Gotardo Merízio, Roberto dos Reis, Hermi Felinto Brito, Lucas Carvalho Veloso Rodrigues, and Maria Claudia França Cunha Felinto
Elsevier BV
Abstract The synthesis of efficient nanosized persistent luminescence materials remains a challenge for the community. Paradoxically, due to the dependence of the point lattice defects and the persistent luminescence efficiency, the control of the defect formation, favorable when the materials are prepared at high temperatures, normally leads to particle growth and sintering. In this work, efficient nanosized rare earth doped disilicates Sr2MgSi2O7:Eu2+,Dy3+ were synthesized via three different wet-chemical methods taking advantages of the microwave-assisted reduction process as a support step to produce high-quality polycrystalline materials. The crystallite size of the sample showed to be smaller when the decomposition temperature of the precursors is higher and close to the phase formation energy. The excitation VUV spectroscopy indicated that despite being nanocrystalline, the materials optical band gap has just a small difference compared one to another. The reduction of Eu3+ to Eu2+ was successfully obtained, since the f-d interconfigurational transitions of Eu2+ 4f65d1→4f7 emission were observed in the blue region of the spectra. The persistent luminescence efficiency measured through its lasting decay time was close to the commercial materials references and with the advantage of having size control during the synthesis method that can lead to the size dependent applications of photonic materials.
Latif U. Khan, Luis F. M. Zambon, Jacinete L. Santos, Rodrigo V. Rodrigues, Luelc S. Costa, Diego Muraca, Kleber R. Pirota, Maria C. F. C. Felinto, Oscar L. Malta, and Hermi F. Brito
Wiley
Thelma A. Kovacs, Maria Cláudia F.C. Felinto, Tiago B. Paolini, Bakhat Ali, Liana K.O. Nakamura, Ercules E.S. Teotonio, Hermi F. Brito, and Oscar L. Malta
Elsevier BV
Abstract Two novel luminescent europium tris ( β -diketonate) complexes [Eu(dbm) 3 ·PX] and [Eu(acac) 3 ·PX] (dbm: dibenzoylmethane, acac: acetylacetonate and PX: piroxicam) were successfully synthesized. These coordination compounds were characterized by infrared vibrational spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and luminescence spectroscopy. The thermal behavior of the complexes was investigated by thermogravimetric analysis (TG) and differential thermogravimetric analysis (DTG) techniques. The optical results have shown that these complexes present a clear intra and inter-molecular energy transfer and corroborates the sensitivity of their emission efficiency to the excitation wavelength, multiphonon non-radiative decays and temperature dependence. These new complexes may act as efficient light converting molecular devices, suggesting that they can be used for controllable photonic applications.
João Resende Filho, Paulo Santos, Juliana Vale, Wagner Faustino, Danyelle Farias, Hermi Brito, Maria Felinto, and Ercules Teotonio
Sociedade Brasileira de Quimica (SBQ)
In this work, synthesis, characterization and photophysical properties of trivalent rare earth complexes with a nonsteroidal anti-inflammatory drug [the indomethacinate (indo), presenting formulas RE(indo)3(H2O)x (x = 3, for Eu and Gd, and x = 4 for Tb), RE(indo)3(bipy) and RE(indo)3(phen) (bipy: 2,2’-bipyridine, and phen: 1,10-phenanthroline)] were investigated. Based on photoluminescent results, the intramolecular energy transfer process from T1 triplet states of indo, phen and bipy ligands to the D0 emitting level of the Eu ion in the coordination compounds is discussed. Accordingly, it is proposed two possible intramolecular energy transfer mechanisms between indomethacinate ligand and rare earth ions, which involve the participation of excited electronic states of the heterocyclic ligands as intermediate ones.
Navadeep Shrivastava, L. U. Khan, J. M. Vargas, Carlos Ospina, J. A. Q. Coaquira, Giorgio Zoppellaro, H. F. Brito, Yasir Javed, D. K. Shukla, M. C. F. C. Felinto,et al.
Royal Society of Chemistry (RSC)
Visible color tunability in ultrasmall LaF3:xCe3+,xGd3+,yEu3+ (x = 5; y = 1, 5, 10, and 15 mol%) NPs depending on the ratio Eu2+/Eu3+.
Navadeep Shrivastava, L. U. Khan, Z. U. Khan, J. M. Vargas, O. Moscoso-Londoño, Carlos Ospina, H. F. Brito, Yasir Javed, M. C. F. C. Felinto, A. S. Menezes,et al.
Royal Society of Chemistry (RSC)
The bifunctional nanocomposite showing strong green emission of Tb3+ ions under a UV lamp (λ = 254 nm), with and without external magnetic field.