Covalent 2D organic nanostructures by optically controlled cross-linking of molecular self-assemblies

Stage M2
France
January 30 2026
February 2 2026
6 month
2025-covalent-2d-organic-nanostructures-by-optically-co-en

Domain, Specialties : Molecular physics
Keywords: polymerization, optics, nanophotonics, plasmonics, local probes, AFM, STM

Research Unit : SPEC / LEPO

Summary

The manufacture of high-quality 2D materials is an important challenge in nanotechnology. Molecular self-assembly makes it possible to create promising supramolecular structures, but these are not stable. The internship aims to study the photo-crosslinking of such assemblies to make them stable, by playing with the degrees of freedom of light.

Full description

The interaction between a material and its environment occurs primarily at its surface. Nano-structuring this surface makes interactions more selective and allows new optoelectronic properties to be obtained. High-quality two-dimensional (2D) materials are therefore an important scientific goal. One promising approach is the self-assembly of molecules on a crystalline substrate. This method is flexible and allows to obtain a wide variety of organized 2D supramolecular networks with promising properties for optoelectronics and sensing. However, these assemblies are based on non-covalent bonds, making them fragile and thermally unstable.

To strengthen these networks, one solution is to bond the molecules together on the surface, thus creating a covalent 2D network. This covalent network formation can be achieved by heating under ultra-high vacuum. However, this method can cause defects in the surface. An interesting alternative is to use light to trigger the cross-linking of the network, which allows for new control parameters: wavelength and polarization of light. We propose to create such molecular assemblies under ambient conditions and characterize them using optics and scanning probe microscopies.

This internship will aim to:

  • Characterize molecular assemblies synthesized by project partners, in air or at the liquid–solid interface, using scanning probe microscopies (scanning tunneling microscopy (STM), atomic force microscopy (AFM) ).
  • Monitor their evolution under light excitation to demonstrate localized photochemical cross-linking under ambient conditions.

Location

CEA Saclay, Site de l’Orme des merisiers (91) Essonne, France

Internship conditions

  • Internship duration: 6 months
  • Level of study: Bac+5
  • Training: Master 2
  • Continuation in PhD thesis: Yes
  • Application deadline: 3 mars 2025

Experimental skills

Language : English

Useful methods and technics:

  • Scanning tunneling microscopy (STM)
  • Atomic force microscopy (AFM)
  • Optical microscopy
  • Absorption spectroscopy
  • Raman spectroscopy

Computer languages and software: Python

Supervisor

Simon Vassant
Phone: +33 1 69 08 95 97
Email :

Head of the laboratory SPEC / LEPO

Ludovic Douillard
Phone: +33 1 69 08 36 26