Photoluminescent Investigation of the Doping Site of Eu3+-Doped [Zn3(BTC)2·12H2O] Metal-Organic Framework Prepared by Microwave-Assisted Hydrothermal Synthesis

Author(s)

César S. Cunha ^[1] ; Oscar L. Malta ^[2] ; Huayna Terraschke ^[3] ; Hermi F. Brito ^[4]

Affiliation

^[1] Universidade de São Paulo. Instituto de Química - Brasil

^[2] Universidade Federal de Pernambuco. Departamento de Química Fundamental - Brasil

^[3] Christian-Albrechts-Universität zu Kiel. Institut für Anorganische Chemie - Alemanha

^[4] Universidade de São Paulo. Instituto de Química - Brasil

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 31, n. 11, p. 2409-2420, 2020-10-30.

Abstract

The [Zn3(BTC)2·12H2O] (BTC = 1,3,5-tricarboxylate) metal-organic framework (MOF) was successfully synthesized using a microwave-assisted hydrothermal synthesis technique, which allowed for significantly decreased reaction time compared to the production of the same compound via conventional heating. In situ doping with Eu3+ ions at concentrations ranging from 1.0 to 5.0 mol% produced doped materials whose emission ranged from blue to red color. The Eu3+ spectroscopic properties were used to study the incorporation of the dopant into the structure of [Zn3(BTC)2·12H2O], even at very low concentrations. These experiments confirmed the usefulness of this ion as a luminescent probe, as it permitted the identification of small variations in structure not perceptible by X-ray diffraction. The variation in the coordination environment induced by increases in doping percentage was analyzed by evaluating changes in the characteristic Eu3+ excitation and emission profiles, using them to calculate luminescence lifetimes, experimental intensity parameters Ωλ (λ: 2 and 4) as well as the intrinsic quantum yield (QEu+3Eu+3) of the 5D0 emitting level of each doped MOF. The excitation and luminescence spectra show that intramolecular energy transfer from the BTC linker to Eu3+ ion, and we could observe the emission color tuning originated from the emissions of the BTC ligand and Eu3+ ion. (AU)

• FAPESP's process: 13/07521-6 - Preparation of supramolecular - MOF systems containing rare earth ions and their photoluminescent properties investigation
• Grantee: Cesar dos Santos Cunha
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 16/03640-9 - High-throughput investigation of new rare earth-doped bismuth-based metal-organic frameworks (MOFs)
• Grantee: Cesar dos Santos Cunha
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)