Covalent integration of Ru-complexes within two-photon patterned photo- and electroluminescent micromaterials

The capability of π-conjugated Ru-complexes as photoinitiators of two-photon polymerization (2PP) of acrylate resulted in an unusual example of ‘one-pot’ direct laser writing of photo and electroactive 3D microstructures with a spatial resolution down to the sub-μm scale. This processing method also allowed the 2D-patterning of electrochemilumiscent materials directly integrated onto electro-active surfaces at the μm-scale.
Covalent integration of Ru-complexes within two-photon patterned photo- and electroluminescent micromaterials

(A). Molecular structures of the RuT et RuF complexes.
(B). Simplified principle of two-photon polymerization (2PP). The two-photon excitation was performed at 800 nm, pulse duration: ~140 fs; repetition rate: 80 MHz; Formulation: PEGDA/PETIA (70 / 30 wt %) with RuL (0.3 % wt).
(C). SEM micrographs of a two-photon polymerized 2D microstructure with its corresponding epiluminescence image.
(D). AFM image of a two-photon polymerized
μ-grid fabricated on a screen-printed gold electrode / ECL-spectrum as a function of the applied potential.

 

This work results from a collaboration of the Rennes Institute of Chemical Sciences (ISCR), the Mulhouse Institute of Material Sciences (IS2M) and the Bordeaux Institute of Molecular Sciences (ISM).


Owing to their high two-photon absorption (2PA) cross sections, the Ru-based complexes RuT (δMAX ∼312 ± 47 GM) and RuF (δMAX ∼597 ± 90 GM) (Scheme A) play a pivotal role as they exhibit a high two-photon initiating ability to fabricate 3D microstructures when directly associated with acrylate-based monomers, as well as an efficient quantum yield for the generation of reactive species that promote monomer cross-linking (Scheme B). Such a direct laser writing strategy resulted in the photopatterning of functional materials with a spatial resolution down to the sub-μm scale (Scheme C). In addition, a covalent integration of the Ru-complex was observed within the polymer matrices implementing for the first time an original electrochemilumiscence (ECL) functionality into two-photon patterned materials (Scheme D).

This approach that judiciously combines two-photon stereolithography and ECL systems clearly paves the way to the future development of new miniaturized ECL-based microsensors and devices  

Reference

  • Micropatterning of electrochemiluminescent polymers based on multipolar Ru-complex two-photon initiators
    Rana Mhanna, Nicolas Durand, Paul Savel, Huriye Akdas-Kiliç, Stephania Abdallah,  Davy-Louis Versace,  Olivier Soppera, Jean-Luc Fillaut, Neso Sojic  and Jean-Pierre Malval
    Chem. Commun., 2022, 58, 9678
    https://doi.org/10.1039/d2cc04159f

Contacts

  • Jean-Pierre Malval, Institut de Science des Matériaux de Mulhouse, UMR 7361 CNRS 
    jean-pierre [dot] malvalatuha [dot] fr
     
  • Jean-Luc Fillaut, Univ Rennes, CNRS, ISCR-UMR 6226, F-35000 Rennes, France
    jean-luc [dot] fillautatuniv-rennes1 [dot] fr

 

Published September 12, 2022