resumo
White-light emitting materials have emerged as important components for solid state lighting devices with high potential for the replacement of conventional light sources. Herein, amine-functionalized organic-inorganic di-ureasil hybrids consisting of a siliceous skeleton and oligopolyether chains codoped with lanthanide-based complexes, with Eu3+ and Tb3+ ions and 4,4-oxybis(benzoic acid) and 1,10-phenanthroline ligands, and the coumarin 1 dye were synthesized by in situ sol-gel method. The resulting luminescent di-ureasils show red, green, and blue colors originated from the Eu3+, Tb3+, and C1 emissions, respectively. The emission colors can be modulated either by variation of the relative concentration between the emitting centers or by changing the excitation wavelength. White light emission is achieved under UV excitation with absolute quantum yields of 0.148 +/- 0.015, 0.167 +/- 0.017, and 0.202 +/- 0.020 at 350, 332, and 305 nm excitation, respectively. The emission mechanism was investigated by photoluminescence and UV-visible absorption spectroscopy, revealing an efficient energy transfer from the organic ligands to the Ln(3+) ions and the organic dye, whereas negligible interaction between the dopants is discerned. The obtained luminescent di-ureasils have potential for optoelectronic applications, such as in white-light emitting diodes.
palavras-chave
METAL-ORGANIC FRAMEWORK; 3 PRIMARY COLORS; COORDINATION POLYMERS; TUNABLE EMISSION; ORGANIC/INORGANIC HYBRIDS; INFRARED TEMPERATURE; MODIFIED SILICATES; INORGANIC HYBRIDS; ENERGY-TRANSFER; QUANTUM YIELDS
categoria
Materials Science
autores
Fang, M; Fu, LS; Ferreira, RAS; Carlos, LD
nossos autores
agradecimentos
This work was financially supported by project POCI-01-0145-FEDER-030351 and was also developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013) and of the project WINLEDS-POCI-01-0145-FEDER-030351, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. This work was also supported by the China Scholarship Council, grant: 201707920002 (2017-2020).