Colorimetry of Luminescent Lanthanide Complexes

Abstract

Europium, terbium, dysprosium, and samarium are the main trivalent lanthanide ions emitting in the visible spectrum. In this work, the potential of these ions for colorimetric applications and colour reproduction was studied. The conversion of spectral data to colour coordinates was undertaken for three sets of Ln complexes composed of different ligands. We showed that Eu is the most sensitive of the visible Ln ions, regarding ligand-induced colour shifts, due to its hypersensitive transition. Further investigation on the spectral bandwidth of the emission detector, on the wavelengths’ accuracy, on the instrumental correction function, and on the use of incorrect intensity units confirm that the instrumental correction function is the most important spectrophotometric parameter to take into account in order to produce accurate colour values. Finally, we established and discussed the entire colour range (gamut) that can be generated by combining a red-emitting Eu complex with a green-emitting Tb complex and a blue fluorescent compound. The importance of choosing a proper white point is demonstrated. The potential of using different sets of complexes with different spectral fingerprints in order to obtain metameric colours suitable for anti-counterfeiting is also highlighted. This work answers many questions that could arise during a colorimetric analysis of luminescent probes.

Eu-Doped Pyrochlore Crystal Nano-Powders as Fluorescent Solid for Fingerprint Visualization and for Anti-Counterfeiting Applications

“…Figure 4 represents the CIE diagram of Y 2 Sn 2 O 7 :x%Eu (x = 7, 8, 9, 10) nanophosphors. The CIE color coordinates of all the pyrochlore phosphors lie in the range (0.64 ± 0.02, 0.36 ± 0.02), which is very close to that of the ideal red light (0.67, 0.33) [ 31 , 32 ].…”

White-light emitting multi-lanthanide terephthalate thin films by atomic/molecular layer deposition

“…1 Trivalent europium is well known for its strong red emission with the strongest emission peaks located around 620 and 700 nm, while Tb 3+ shows an intense green emission around 545 nm and also a weak blue emission at 490 nm. 8 Hence, these two Ln 3+ species have been combined with a blue emitting lanthanide such as Ce 3+ , Eu 2+ , Dy 3+ , and Tm 3+ . [9][10][11] Blue emitters can also be used in combination with yellow or orange colour emitters such as Ce 3+ or Sm 3+ .…”

Synthesis of Novel Luminescent Double-Decker Silsesquioxanes Based on Partially Condensed TetraSilanolPhenyl POSS and Tb3+/Eu3+ Lanthanide Ions

“…From an optical point of view, it is widely known that lanthanides exhibit sharp absorption bands with unique well-defined optical emissions in the NIR-UV-Vis range, long-lived excited state lifetimes and remarkable photostability [81,82]. Furthermore, lanthanide ions, such as Gd 3+ , Dy 3+ and Ho 3+ , possess specific chemical properties in terms of high effective magnetic moment and variable electronic relaxation times, which make them suitable for bioimaging [83][84][85][86] and electronic applications [87][88][89][90][91][92].…”