High red luminescence intensity under sunlight exposure of a PMMA polymer doped with a tetrakis Eu³⁺ β-diketonate complex containing a benzimidazolium counterion

Author(s)

Assuncao, Israel P. ; Costa, Israel F. ; Blois, Lucca ; Felinto, Maria Claudia F. C. ; Deflon, Victor M. ; Ando, Romulo A. ; Malta, Oscar L. ; Brito, Hermi F.

• Document type: Journal article
• Source: RSC ADVANCES; v. 15, n. 1, p. 11-pg., 2025-01-02.

Abstract

New tetrakis Eu3+ and Gd3+ beta-diketonate complexes containing benzimidazolium (Bzim) as the counterion were synthesized by the one-pot method. The Bzim[Eu(tta)4]<middle dot>H2O complex was further incorporated into a poly(methyl methacrylate) matrix (PMMA) at 1, 5, and 10% (w/w), which revealed highly desirable photonic features. The Eu3+ and Gd3+ complexes were characterized by elemental and thermal analyses, in addition to ESI-MS spectrometry, FTIR, and Raman spectroscopy. Single-crystal X-ray diffraction studies of the tetrakis Bzim[Eu(tta)4]<middle dot>EtOH complex revealed that the Bzim+ counteraction and EtOH molecules exhibited several intermolecular interactions with very short hydrogen bond distances between two [Eu(tta)4]- anion units. The PMMA:(1%) Bzim[Eu(tta)4]-doped material was thermally stable up to 120 degrees C, which was close to the values found for the Eu3+-complex. Regarding the photoluminescence properties, either the Bzim[Eu(tta)4]<middle dot>H2O or the doped films showed intense emission arising from the metal ion over a wide range of excitation wavelengths comprising UVA, UVB, and UVC regions. In addition, when the polymer films were exposed to sunlight radiation in an open external environment, the materials revealed a high Eu3+-centered red emission arising from the 5D0 -> 7FJ transition. The Bzim[Eu(tta)4]<middle dot>H2O and Bzim[Eu(tta)4]<middle dot>EtOH complexes showed high absolute quantum yields (QLEu) of 56% and 70%, respectively, whereas the doped polymer films displayed only similar to 38%. All materials exhibited a highly red monochromatic emission characteristic. We believe that such luminescent systems could be promising photonic materials with a wide excitation range, including UVA, UVB, UVC, and sunlight, acting as efficient light-converting molecular devices (LCMDs). (AU)

• FAPESP's process: 22/12709-3 - Photophysical properties of lanthanide charge transfer complexes with organic semiconductors for applications in OLEDs
• Grantee: Israel Ferreira da Costa
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/08111-2 - Development of rare earth based light converters: luminescent markers, optical sensors, and amplifiers
• Grantee: Hermi Felinto de Brito
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/11983-4 - Spectroscopy signal enhancement: nanomaterials, theory, and computer simulation
• Grantee: Mauro Carlos Costa Ribeiro
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/16795-6 - Intramolecular energy transfer processes in rare-earth beta-diketonate complexes investigated by means of transient absorption spectroscopy
• Grantee: Lucca Blois Guimarães
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)