In this article, imaging applications of luminescent complexes and recent advances in the design and photophysical behaviour of near‐IR responsive complexes are reviewed. Various properties of the luminescent lanthanide complexes are also discussed in detail.

Lanthanide Complexes for Luminescence Imaging Applications

Fluorescence yields and lifetimes of solutions of europium and terbium salts in solution are greatly enhanced by using deuterated solvents. The magnitude of increase varies from an 18‐fold enhancement in yield and lifetime for an aqueous solution of europium nitrate to a twofold enhancement for europium ethylenediaminetetra‐acetate dissolved in methanol. The enhancement is proportional to the fraction of deuterated solvent present. Results lead to conclusions that the dominant mode of radiationless deactivation of a rare‐earth ion in solution is via loss of energy to hydrogen vibrations. Further, such loss is proportional to the number of hydrogen vibrations in the local rare‐earth environment. Values for the rate constant for radiationless loss of energy to hydrogen vibrations are determined for the salts studied. The influence upon radiationless processes of complexing between the rare earth and anion is discussed. Likewise the dependence of the enhancement factor upon the rare‐earth ion is considered. ...

Luminescence and Energy Transfer in Solutions of Rare‐Earth Complexes. I. Enhancement of Fluorescence by Deuterium Substitution

The luminescence of trivalent lanthanide ions has found applications in lighting, lasers, optical telecommunications, medical diagnostics, and various other fields. This introductory review present...

https://journals.sagepub.com/doi/pdf/10.3184/003685005783238435

Making sense of Lanthanide Luminescence

Absorption spectra and structure of lanthanide coordination compounds in solution

Luminescent lanthanide(III) complexes show narrow emission bands (full widths at half maximum < 10 nm in the visible region) based on 4f–4f transitions, which are suitable for application in displays and sensing devices. The temperature-dependent luminescence of lanthanide complexes is expected to be applied to effective temperature-sensitive paints with higher sensitivity over a wide range for measurements of the physical parameters of a material surface in the fields of fluid dynamics, aeronautical engineering, environmental engineering, and energy technology. In this review, the characteristic emissions of lanthanide ions, suitable detection systems for thermo-sensing properties, temperature dependent luminescence of lanthanide mononuclear complexes, polynuclear clusters, coordination polymers (CPs) and metal–organic frameworks (MOFs) are introduced. The theoretical considerations of their temperature-dependent photophysical processes and advanced ratiometric sensing systems for precise temperature detection are also described. Studies on luminescent lanthanide complexes with thermo-sensing properties open up the frontier field of research in advanced materials chemistry.

Thermo-sensitive luminescence of lanthanide complexes, clusters, coordination polymers and metal–organic frameworks with organic photosensitizers

Changes in the environment of europium ions in solution bring about changes in the structure of the absorption spectrum. For example, an aqueous solution of europium chloride upon having potassium nitrate added to it gives rise to the structures in the spectra of europium nitrate, in addition to the spectrum of europium chloride. Structures in the spectra of europium salts in alcohol differ from those in water. In a mixed solvent of water and alcohol both spectra are present with relative intensities which vary according to the relative amounts of the components. Europium chloride in the mixed solvent has a spectrum which cannot be distinguished from the exact superposition of the spectra of europium chloride in pure water and in pure alcohol. However, the spectrum of europium nitrate in the mixed solvent has its lines shifted from the positions they occupy in the spectra of the nitrate in the pure solvents. The shifts seem to vary continuously with the proportions of water to alcohol. Nevertheless, the l...

Fred E. Fortess

Papers

Ions of Europium Distributed Between Different Configurations in Homogeneous Solutions

The Absorption Spectra of Ions of Europium and the Electric Fields within Some Coördination Compounds