Photoluminescent Investigation of the Doping Site of Eu3+-Doped [Zn-3(BTC)(2)center dot 12H(2)O] Metal-Organic Framework Prepared by Microwave-Assisted Hydrothermal Synthesis

Author(s)

Cunha, Cesar S. ; Malta, Oscar L. ; Terraschke, Huayna ; Brito, Hermi F.

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 31, n. 11, p. 12-pg., 2020-11-01.

Abstract

The [Zn-3(BTC)(2)center dot 12H(2)O] (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 [Zn-3(BTC)(2)center dot 12H(2)O], 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 Omega(lambda) (lambda: 2 and 4) as well as the intrinsic quantum yield (Q(Eu3+)(Eu3+)) of the D-5(0) 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: 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)