High relative thermal sensitivity of luminescent molecular thermometer based on dinuclear [Eu-2(mba)(4)(mu-mba)(2)(H2O)(2)] complex: The role of inefficient intersystem crossing and LMCT

Author(s)

Galico, D. A. ^[1] ; Souza, E. R. ^[1] ; Mazali, I. O. ^[1] ; Sigoli, F. A. ^[1]

Affiliation

^[1] Univ Estadual Campinas, Inst Chem, Lab Funct Mat, UNICAMP Campinas, POB 6154, BR-13083970 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of Luminescence; v. 210, p. 397-403, JUN 2019.
• Web of Science Citations: 0

Abstract

In this work, the photophysical properties of the {[}Eu-2(mba)(4)(mu-mba)(2)(H2O)(2)] is evaluated as a function of temperature. The luminescence intensity ratio (LIR) between the ligand emission and the D-5(0) -> F-7(2) transition band area is analyzed giving a maximum relative sensitivity of 4.55% K-1 at 313 K and a temperature uncertainly smaller than 0.015 K over the operational range (203-313 K) making this complex as a promising molecular temperature optical probe. These results may be explained by the small energy difference between the excited singlet (S-1) and triplet (T-1) states (similar to 1400 cm(-1)) leading to an inefficient intersystem crossing and consequently the fluorescence of the ligand competing with the D-5(0) state emissions. The Mott-Seitz model involving three non-radiative recombination channels suggests that the europium(III) emission deactivation involves the energy back transfer to ligand states, the ligand-to-metal charge transfer state and the third harmonic of the O-H oscillator from a coordinated water molecule. (AU)

• FAPESP's process: 14/50906-9 - INCT 2014: in Functional Complex Materials
• Grantee: Fernando Galembeck
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/22127-2 - Development of novel materials strategic for integrated analytical devices
• Grantee: Lauro Tatsuo Kubota
• Support Opportunities: Research Projects - Thematic Grants