USP
Universidade de São Paulo

Hermi Felinto de Brito

Professor Titular - Departamento de Química Fundamental
FOTO E ELETROLUMINESCÊNCIA DE TERRAS RARAS
3091-3847 
 hefbrito@iq.usp.br

Homepage Principal

 

Resumo

As aplicações baseadas na fotoluminescência de íons TR têm alcançado uma posição importante na sociedade moderna. Por exemplo, os fósforos de TR (Sm, Eu, Tb, Tm) são usados em iluminação, lasers, fibras ópticas, tubos de raios catódicos etc. Um dos nossos objetivos é estudar as propriedades fotoluminescentes de compostos de TR que comportem como dispositivos moleculares conversores de luz (DMCL). Os íons TR apresentam propriedades fotofísicas singulares, exibindo espectros com bandas extremamente finas. Os complexos apresentam altos rendimentos quânticos tornando-se promissores na aplicação como marcadores ópticos e fluoroimunoensaios. Além disso, as propriedades eletroluminescentes destes complexos apresentam potencialidades para o desenvolvimento de dispositivos orgânicos emissores de luz (OLEDs). O nosso grupo vem se dedicando ao estudo fotoluminescente de complexos de TR com diferentes ligantes orgânicos: dicetonatos AZT, peptídeos, calixarenos, polímeros, amidas, carboxilatos, sulfóxidos etc. Temos investigado também as propriedades luminescentes de nanomateriais de TR com tungstatos, vanadatos, alumina, boratos etc. Em 2004, iniciou-se projeto de pesquisa visando desenvolver nova geração de fósforos contendo íons TR. Estes materiais luminescentes apresentam alta persistência luminosa, com duração superior a 10 horas, após irradiações de luz solar, UV etc... Estes materiais encontram aplicação, dentre outras, como sinalizadores de segurança, sinais de trânsito, iluminação de emergência, painéis automotivos, pintura luminosa, relógios, mostradores, estamparia têxtil e em cerâmicas. Ademais, o nosso grupo de pesquisa vem atuando na área de marcadores luminescentes em sistemas biológicos.

 

Summary

 The research on the luminescent materials containing rare earth ions (RE) has increased considerably in the last three decades. Major applications are in emissive displays and fluorescent lamps, laser, fluoroimmunoassay. The luminescence of RE complexes has intensively been studied due to the possible applications as light conversion molecular devices (LCMD). The RE ions have extraordinary photophysical properties due to these ions present very narrow bands in their emission and absorption spectra. We have also studied the electroluminescent properties of the organic light emitting devices (OLEDs). The advantages of using the RE ions are the inner quantum yield is near 100% which is four times higher of that similar organic devices and the sharp emission bands. Our group has devoted to photoluminescent study of the rare earth complexes containing different organic ligands: diketonates, AZT, peptides, calyxarene, polymers, amides, carboxylates, sulfoxides etc. We have also investigated the luminescence properties of rare earth nanomaterials such as tungstate, vanadate, alumina, borates etc. In 2004, it was started the project to develop a new generation of phosphors with RE íons. These luminescence materials present high persistence luminescence, which phenomenon that a phosphor after exposure to UV light (day light) shows visible luminescence in the dark that persist during whole night (~10 h). Persistent luminescence materials can be applied as safe traffic, marking of roads, important devices and control elements, wall painting, as well as a filler for plastics, films, artificial fibres, rubbers, textiles and ceramics.Moreover, our research group has been working in the field of luminescent markers in biological systems.

 

 

 

Produção científica

Curriculo (Sistema Lattes - CNPq)

Curriculo (Sistema Researcher ID)

 

  1. Carvalho, José M.; Rodrigues, Lucas C.V.; Felinto, Maria C.F.C.; Nunes, Luiz A.O.; Hölsä, Jorma; Brito, Hermi F.. Structure-property relationship of luminescent zirconia nanomaterials obtained by sol-gel method. Journal of Materials Science, v. 50, p. 873-881, 2015.
  2. ARAGON, FERMIN H.; GONZALEZ, ISMAEL JOSE; COAQUIRA, JOSE A.H.; HIDALGO, PILAR; Brito, Hermi F.; ARDISSON, JOSÉ D.; MACEDO, WALDEMAR AUGUSTO DE ALMEIDA; MORAIS, PAULO C.. Structural and Surface Study of Pr-doped SnO2 Nanoparticles Prepared by the Polymeric Precursor Method. Journal of Physical Chemistry. C, v. 119, p. 150330192207008-8717, 2015.
  3. SILVA, IVAN G.N.; MUSTAFA, D.; ANDREOLI, B.; FELINTO, MARIA C.F.C.; MALTA, OSCAR L.; Brito, Hermi F.. Highly luminescent Eu3+-doped benzenetricarboxylate based materials. Journal of Luminescence, v. xx, p. xxx-xxx, 2015.
  4. MIRANDA, YOLANDA C.; PEREIRA, LEIDE L.A.L.; BARBOSA, JOSÉ H. P.; Brito, Hermi F.; FELINTO, MARIA C.F.C.; MALTA, OSCAR L.; Faustino, Wagner M.; Teotonio, Ercules E. S.. The Role of the Ligand-to-Metal Charge-Transfer State in the Dipivaloylmethanate-Lanthanide Intramolecular Energy Transfer Process. European Journal of Inorganic Chemistry (Print), v. 1, p. 3019-3027, 2015. 
  5. RODRIGUES, R.V.; MACHADO, L.C.; MATOS, J. R.; MURI, E.J.B.; MARINS, A.A. L.; BRITO, H.F.; PASSOS, C.A.C.. Oxysulfate/oxysulfide of Tb3+ obtained by thermal decomposition of terbium sulfate hydrates under different atmospheres. Journal of Thermal Analysis and Calorimetry, v. xx, p. xxx-xxx, 2015.
  6. FULGÊNCIO, F. ; BORGES, A.S. ; ARAÚJO, M.H.; BRITO, H.F.; OLIVEIRA, F.C.; RIBEIRO, T.; WINDMÖLLER, D.; MAGALHÃES, W.F.. Participation of electronic excited states in the positronium formation mechanism in the Gd(III) pentakis (picrate) complexes with imidazolium countercations. Journal of Luminescence, v. xx, p. xxx-xxx, 2015.
  7. SOUZA, A.S.; NUNES, L.A.; FELINTO, M.C.F.C.; BRITO, H.F.; MALTA, O.L.. On the quenching of trivalent terbium luminescence by ligand low lying triplet state energy and the role of the 7F5 level: the [Tb(tta)3 (H2O)2] case. Journal of Luminescence, v. 167, p. 167-171, 2015.
  8. FOSTER, P.L.; PARRA, DUCLERC, F.; LUGAO, ADEMAR, B.; KAI, JIANG; BRITO, H.F.. Highly luminescent polycaprolactone films doped with diaquatris(thenoyltrifluoroacetonate)europate(III) complex. Journal of Luminescence, v. 167, p. 85-90, 2015.
  9. AGUIAR, FRANKLIN P.; COSTA, ISRAEL F.; ESPÍNOLA, J.G.P.; FAUSTINO, W.M.; MOURA, JANDEILSON L.; BRITO, H.F.; PAOLINI, TIAGO B.; FELINTO, M.C.F.C.; TEOTONIO, ERCULES, E.S.. Luminescent hybrid materials functionalized with lanthanide ethylenodiaminotetraacetate complexes containing β-diketonate as antenna ligands. Journal of Luminescence, v. xx, p. xxx-xxx, 2015.
  10. CARVALHO, J.M.; LASTUSAARI, M.; RODRIGUES, L.C.V.; HOLSA, J.; FELINTO, M.C.F.C.; BRITO, H.F.. Valence control of Pr in ZrO2 nanocrystals by aliovalent Gd3+ co-doping. Journal of Luminescence, v. x, p. xxx-xxx, 2015.
  11. RODRIGUES, L.C.V.; HOLSA, J.; BRITO, H.F.; MARYKO, M.; MATOS, J.R; PATURI, PETRIINA; RODRIGUES, R.V.; LASTUSAARI, M.. Magneto-optical studies of valence instability in europium and terbium phosphors. Journal of Luminescence, v. x, p. xxx-xxx, 2015.
  12. BARBOSA, HELLIOMAR P.; Kai, Jiang; Silva, Ivan G.N.; RODRIGUES, L.C.V.; FELINTO, M.C.F.C.; HOLSA, J.; MALTA, O.L.; BRITO, H.F.. Luminescence investigation of R3+-doped alkaline earth tungstates prepared by a soft chemistry method. Journal of Luminescence, v. xx, p. xxx-xxx, 2015.