Ongoing projects

One of the main challenges of our generation is securing the global energy supply while fighting global warming. In this sense, solar energy is a great alternative since several materials can convert sun light into electricity. Despite the high efficiency of silicon panels, our unstoppable energy consumption demands additional alternative materials. Particularly, organic molecules are the most versatile choice since it is possible to control the materials’ properties by rational molecular design. CHIROTRONICS will contribute to the advance of alternative energy materials by introducing supramolecular chemistry strategies involving hydrogen-bonding and chirality. More particularly, we want to explore the role of chiral supramolecular assemblies in charge transport processes following the recently reported Chiral Induced Spin Selectivity (CISS) effect, which states that electrons of certain spin can go through chiral assemblies preferentially in one direction depending on their handedness. CHIROTRONICS will help identifying the most optimal supramolecular chiral structures to be incorporated in electronic devices. The interdisciplinarity of CHIROTRONICS involves organic synthesis, self-assembly studies and charge transport screening thanks to local and international collaborations, providing the best environment to develop this project

• Participants / Institutions:  
  • A. Ruiz Carretero / STELORG - ICS
  • T. Heiser / STELORG - ICUBE
• Funding: 
  • Unistra - IDEX exploratoire

The project utilizes a reverse engineering  methodology based on computer-assisted molecular design and genetic algorithms coupled with experimental studies to identify alternative bio-sourced  solvents  with low toxicity that allow the elaboration of efficient organic solar cells wih  negligible  impact on the environment and human health.

• Participants / Institutions : 
  •  I. Rodriguez-Donis, S. Thiebaud-Roux, L.E. Ramirez-Cardena / Laboratory of Agro-Industrial Chemistry, Toulouse.
  • T. Heiser, S. Fall, P. Lévêque / STELORG - ICUBE 
  • V. Gerbaud / Chemical Engineering Laboratory, Toulouse
  • U. Würfel, M. Kohlstädt / Freiburg Materials Research Center, Freiburg, Germany
• Funding: 
  • ANR - PRCI, DFG

This project aims to develop the chemistry of n-type materials according to two approaches which can ultimately converge : The synthesis of electro-deficient SCO polymers of homogeneous electronic nature i.e. consisting of aromatic units having close boundary molecular orbitals and The synthesis of electro-deficient SCO polymers carrying solubilizing chains of crown ether type in order to control the doping with alkali metals.

• Participants / Institutions:  
  • N. Leclerc, B. Jismy / STELORG - ICPEES
• Funding: 
  • Unistra - IDEX post-doc

The active matrix of an organic field effect transistor (OFET) is a thin film of semiconducting organic small molecules or polymers. Small molecules display higher efficiencies but more difficult processing. These molecules have planar structures with extended π-electron delocalised surfaces which tend to aggregate and stack in the solid phase. This tight stacking leads directly to high charge mobilities but renders solution processing challenging. Alkyl chains can be appended to these structures to improve processability, but this often occurs at the expense of performance.
Performance in many OFETs suffer under thermal stress due to increased molecular motion at high temperatures and this is exacerbated using alkyl chains as solubilising groups as they have a high degree of flexibility and can also provide degradation pathways.
New molecules which exploit three-dimensionally defined ring-fused iptycene and bicycloalkane fragments as high thermal stability solubilising groups, employed in conjunction with hydrogen bonding to harness intermolecular interactions reveals a new generation of thermally robust molecular materials for high-temperature OFET device

• Participants / Institutions:
  • N. Leclerc, G. Ulrich / STELORG - ICPEES
  • WRIGHT LOUGHBOROUGH UNIVERSITY (UK)
• Funding:
  • DSTL

Chiral semiconductors are promising new materials in the organic photovoltaics field. When charge carriers are created, a preferred spin could be transmitted through a determined handedness structure as recently described by the chiral-induced spin selectivity (CISS) effect. Here, we propose to optimise the CISS effect by strategically changing the molecular structure of monomers that form chiral fibers. We employ a fast screening method to quantify the CISS effect without fabricating entire photovoltaic devices. Namely, we will use contactless microwave spectroscopy pioneered by Prof. Shu Seki, allowing for a full characterization of spin states and charge carrier transport in simple thin films. Once we have a good understanding of how molecular and supramolecular structure relates to the CISS effect, we can provide handles to the photovoltaics community to obtain superior devices. 

• Participants / Institutions:
  • A. Ruiz-Carretero, A. Garcia, K. Hong  / STELORG - ICS
  • S. Seki / KYOTO UNIVERSITY (JAPAN)
• Funding:
  • USIAS

What if body heat could power wearable devices, medical monitors and watches with ultralight, cheap and flexible thermoelectric devices? BODYTEG project aims at taking advantage of the very low thermal conductivity of aerogels made of highly conducting polymers to elaborate new thermoelectric generators. On this basis, BODYTEG has accordingly four main objectives: i) producing both p- and n-type conductive polymer aerogels (CPAs) with controlled morphology, ii) taking benefit of the porous network to decrease the thermal conductivity of the CPAs, iii) maintaining good mechanical and electrical properties of the aerogel, iv) correlate the structure of the CPAs with their electrical and thermal properties. 

• Participants / Institutions:
  • L. Biniek, Q. Weinbach / STELORG - IC 
• Funding:
  • ANR JCJC

The race for achieving efficiency records in organic electronics has hampered research focused on solving other fundamental issues. Likewise, the time consuming processes to optimize device performance, make the study of new systems very challenging. This is the case of hydrogen-bonded semiconductors, which have shown promising results in devices, but that are still not well understood. Recently, techniques based on dielectric loss spectroscopy of microwaves have been developed as noncontact methods to monitor the charge-carrier properties of semiconductors. This way, the effect of external factors that make electrical measurements very difficult is minimized. Prof. Seki is a pioneer world expert in these techniques; thanks to our collaboration, a detailed study of possible influencing parameters on H-bonded semiconductors is being performed. Besides, our work is being extended to other techniques involving magnetic fields to study chiral molecules that could behave as spin filters

• Participants / Institutions: 
  • A. Ruiz-Carretero  / STELORG - ICS
  • S. Seki / KYOTO UNIVERSITY (JAPAN)
• Funding: 
  • CNRS - IEA

THERMOPOLYS develops two innovative strategies to design new efficient and stable n-type thermoelectric polymers. The first strategy combines the original synthesis of new n-type homo-acceptors and controlled processing methods for polymer alignment/crystallization and doping to fine tune and optimize the structure and TE properties of doped polymer films. The second strategy exploits the original p n polarity switch observed in alternated donor-acceptor copolymers doped with strong oxidants with the aim to identify the macromolecular parameters and doping conditions that help optimize TE performances and stability in highly oriented thin films. Ultimately, this project will generate new polymer TE materials with power factors higher than 200 W/mK2 and efficiency ZT>0.05.
Thermoelectric (TE) materials have the capability to convert heat to electricity. Doped conjugated polymers (CPs) have emerged as promising materials since they are light, flexible, easy to process and can be operated at low temperatures. Efficient p-doped and n-doped CPs are required to build TE generators. Despite significant progress made on TE CPs in the last decade, doped n-type CPs still show modest TE performances and stabilities. This project explores two innovative strategies for the fabrication of new stable and efficient n-type thermoelectric polymers. The first approach combines the original synthesis of new n-type full-acceptor polymers and the implementation of orientation/crystallization and controlled doping methods, already successfully explored on p-type polymers, in order to optimize the structures and TE properties of polymer thin films. The second approach exploits the p n Seebeck polarity switch observed when a p-type alternating donor-acceptor copolymer is strongly doped by an oxidant, with the objective of identifying the macromolecular parameters influencing this polarity inversion as well as the underlying physical mechanism.
Finally, this project aims at obtaining new n-type TE polymers with power factors higher than 500 W/mK2.

• Participants / Institutions: 
  • N. Leclerc  / STELORG - ICPEES
  • M. Brinkmann / STELORG - ICS
  • F. Tran-Van, B. Schmaltz  / Laboratoire de Physico-Chimie des Matériaux et des Electrolytes pour l’Energie, Tours

  • P. Limelette / GREMAN, Tours

• Funding: 
  • ANR - PRC

TOTALBOND aims to understand the role and impact of hydrogen-bonds (H-bonds) in organic electronics with the aim of introducing them in organic semiconductors and applying them efficiently in devices. Particularly, TOTALBOND intends to do a systematic study starting with a library based on a simple thiophene-capped diketopyrrolopyrrole (DPP) electroactive segment) as a model system varying several H-bonding parameters semiconductors. 

• Participants / Institutions:   
  • A. Ruiz Carretero, G. Martinez, R. Avila Rovelo, I.Bourbrik / STELORG - ICS 
• Funding:  
  • ANR - JCJC

The objectives of the COMPOMOF project are to explore the possibilities of synthesizing hierarchical structures combining MOFs (Metal-Organic-Framework) and porous conducting polymers as well as to initiate a new theme on 2D MOFs. Thanks to a nanoprobing station under electron microscopy, we want to study for the first time, at different scales and depending on the organisation and orientation of the structural domains, the physical properties (conductivity, mobility of charge carriers, photo-conduction), their band structure by Angle Resolved Photoelectron Spectroscopy (ARPES) and their potential for thermoelectric applications.

• Participants / Institutions:   
  • L. Biniek / STELORG - ICS
  • N. Leclerc / STELORG - ICPEES
  • G. Chaplais, L. Simon / IS2M
• Funding:  
  • ITI HiFunMat - SEED MONEY