Laboratoire de Physique des Interfaces et des Couches Minces

CNRS - École polytechnique - Institut Polytechnique de Paris

pi-Conjugated Materials for Electronics

Written by : Abderrahim Yassar

Our research interests are focused on the design, synthesis and characterization of pi-conjugated small molecules and polymers with potential applications in the fields of organic electronics and material sciences. Advanced organic synthetic methodologies are used. The intrinsic properties are studied by modern physical organic methods (electronic spectroscopies, cyclic voltammetry…), and the structure-property relationship of these novel systems are investigated. Their supramolecular structure permits self-assembly via π-stacking, making them attractive tunable optical and electronic targets with tailor-made optoelectronic properties. These conjugated molecules are also used to develop the design of 2D and 3D micro- and nanohybrid structures for the further development of electronic devices. We particularly focus on solution processing methods (spin coating, Doctor Blade, ink-jet printing and 3D-laser printing).

Functional conjugated materials
Mixed ionic-electronic organic semiconducting materials have the virtue of being mechanically flexible and biocompatible. They are chemically tunable, solution-processable, they have easily modifiable surface structure, and possess mixed ionic and electronic charge transport. They recently emerged as new materials in many applications such as energy storage e.g., batteries and supercapacitors, transconductance in bioelectronics and organic electrochemical transistors. We demonstrated that a class of amphiphilic rod–rod diblock copolymers, containing nonpolar (hexyl) and polar (triethylene glycol) side chains can be used as a biointerface material for label-free impedimetric detection of Escherichia coli (E. coli). Self-assembly and film formation of P3HT-b-P3TEGT were analyzed by 2D-NMR, Fourier transform infrared, dynamic light scattering, contact angle, and microscopy characterizations. The obtained sensing layer demonstrates targeting ability toward E. coli pili protein with a detection range from 103 to 107 cfu/mL, and its selectivity was studied with Gram(+) bacteria.


We have extended our work to investigate the microbial sensing of fluorescent conjugated polymer nanoparticles (NPs). CTAB-P3HT NPs show a multiple pathogenic bacteria detection and antifungal activity, without the requirement of light with good biocompatibility towards normal human cells. (

Solution processing methods
Meniscus guided coating methods are considered simple, efficient, and low-cost methods to fabricate large-area electronic devices. One of the major challenges is the control of thin film morphology, molecular orientations and directional alignment of polymer films during coating processes. We recently report on a systematic study of the fabrication of large-scale patterning π-conjugated polymers using meniscus guided method.

Micro-Raman spectra of P3HT film coated with a doctor blade technique, at 0.1 mm.s−1, showing a well patterning film with periodic grooves and stripes.