Excited state properties of lanthanide complexes: Beyond ff states

Sol–gel synthesis, paramagnetism, photoluminescence and optical properties of Gd-doped and Bi–Gd-codoped hybrid organo-silica glasses

“…The identification of these IL states should be facilitated by the absence of other low-energy excited states. Thus, several Gd(III) chelates are characterized by a room temperature phosphorescence which extends from the UV to the red spectral region depending on the ligands [52][53][54]. Similar effects were found by others [33].…”

“…ions neither should show fluorescence nor should be the source of phosphorescence in the visible and near infrared (NIR) regions [33]. This is certainly because neither metalcentered f-f transitions nor CT (MLCT or LMCT) occur at such low energies [33,[52][53][54]. Owing to the small absorption coefficients of Ln 3?…”

Visible‐Light Excitation of Infrared Lanthanide Luminescence via Intra‐Ligand Charge‐Transfer State in 1,3‐Diketonates Containing Push‐Pull Chromophores

“…[4] Whereas energy transfer from the triplet state of the chromophore moiety is often a preferred (and commonly invoked) pathway for the sensitization of the metal ion luminescence, several other mechanisms can be operative, which involve the ligand singlet state, [5,6] metal-to-ligand charge-transfer (MLCT) states, [4] or intra-ligand charge-transfer (ILCT) states. [7][8][9] One of the challenges in the design of luminescent lanthanide tags, particularly those aimed at bioanalyses and bioimaging, is to shift the excitation wavelength from the UV to the visible range, for both an intrinsic reason, since biomolecules are usually damaged by UV light, and a practical one, visible excitation requiring cheaper optical cells and optics. Several strategies have been proposed towards this goal, for instance excitation through d-metal ions, [2,4,10] by multiphoton excitation, [11][12][13][14] or via ILCT states [7][8][9]15] which may have relatively low energy.…”

“…[7][8][9] One of the challenges in the design of luminescent lanthanide tags, particularly those aimed at bioanalyses and bioimaging, is to shift the excitation wavelength from the UV to the visible range, for both an intrinsic reason, since biomolecules are usually damaged by UV light, and a practical one, visible excitation requiring cheaper optical cells and optics. Several strategies have been proposed towards this goal, for instance excitation through d-metal ions, [2,4,10] by multiphoton excitation, [11][12][13][14] or via ILCT states [7][8][9]15] which may have relatively low energy. For instance, we recently showed that energy can be transferred from bodipy (a boradiazaindacene-appended terpyridine at 400-550 nm which was utilized to achieve visible-light excitation of metal-centred infrared luminescence of Nd III with maximum absorption at 529 nm) to Nd III , Er III , and Yb III .…”

Photoemissive polymer composite based on new Y(III), Gd(III), and Tb(III) complexes with N-hydroxyphthalimide

“…The broadband emission spectrum is centered on a peak located at 500 nm, most probably due to radiative transitions occurring through the influence of the central cation over the excited states of the surrounding ligands. 27 The excitation spectrum revealed also a broader band peak located in the UV-A region at 380 nm. Figure 5b presents the excitation/emission spectra of the yttrium complex.…”