The application of rare-earth complexes in electrically driven light sources poses a series of challenges that require specific optimization of the molecular photophysical properties. Here, we present a report on films of three different Eu3+ complexes characterized in terms of emission spectra and fluorescence decay. We compare molecular complexes in powder form and sublimed films, in films on glass and on a metal surface, and in films of thicknesses down to less than 3 nm (< 3 ML), approaching electrical coupling. Our photoluminescence experiments supported by scanning tunneling microscopy of sub-monolayers indicate that Eu3+(trensal) complexes are less affected by sublimation and more stable on the metal surface than typical beta diketonate complexes, making them promising candidates for electroluminescence devices.
@article{arxiv.2602.16377,
title = {Photophysical properties of Eu3+ complexes approaching electronic contact to a metal surface},
author = {Adrian Ebert and Simon Fromme and Lisa Burgert and Umar Rashid and Lukas Gerhard and Julia Feye and Senthil Kumar Kuppusamy and Barbora Brachnakova and Timo Neumann and Mario Ruben and Peter W. Roesky and Michael Seitz and Wulf Wulfhekel},
journal= {arXiv preprint arXiv:2602.16377},
year = {2026}
}