At the Institut national de la recherche scientifique (INRS), the aim of Professor Emanuele Orgiu is to determine the best materials for future electronics. Some of the materials in which Professor Orgiu shows interest are made of molecules with the ability to conduct electricity.
Emanuele has illustrated the role of molecular vibrations on electron conductivity on crystals of these materials. This discovery is crucial for applications of such molecular materials in energy, electronics, and information storage.
Performed in collaboration with a research team from the INRS and the University of Strasbourg (France), the study was published in the renowned journal Advanced Materials.
Researchers showed great interest in finding the relationship between the structure of materials and their potential to conduct electricity. For this purpose, they quantified the speed of propagation of electrons in crystals developed by such molecules.
As part of the study, the researchers made a comparison between two perylene diimide derivatives— semiconducting molecules of interest due to their applications in foldable electronics, smart clothes, or flexible devices.
Both the compounds analyzed in the study exhibit similar chemical structure but very different conduction properties.
The researchers intended to find out what created this variance and could discover that the different molecular vibrations composing the material caused the different electrical behavior noted in devices. This group was the first to show which vibrations have the highest impact on electron flows.
For a current to flow through a material, electrons must ‘hop’ from one molecule to the neighboring one. Depending on the level of ‘movement’ of the molecules, which depends on the amplitude and energy of the related vibrations (called phonons), the electrons can move more or less easily through the material.
Emanuele Orgiu, Professor and Scientific Director, Molecular and Device Physics Laboratory, INRS
An Ad Hoc Molecular Design to Make Electrons Travel Faster
This discovery opens the door for the advent of much more efficient materials for electronics.
By knowing what type of vibrations allows charges to move more easily, we are providing chemists with a formula for synthesizing the right materials, rather than going in blindly.
Marc-Antoine Stoeckel, Study First Author and Doctoral Student, University of Strasbourg
This study provides new applications that could not be foreseen with silicon, the most extensively utilized material in electronics, such as computers.
Professor Orgiu joined hands with INRS Professor Luca Razzari to quantify the vibrations of the molecules. At present, both the scientists are working on a new spectroscopic method that would allow them to observe the vibrations in the presence of electrons. This will enable them to analyze whether charges have an impact on molecular vibrations.
Professor Orgiu began this study while he was a professor at the University of Strasbourg. He co-supervised the thesis of Marc-Antoine Stoeckel, when he was a doctoral student at the University of Strasbourg and first author of the study, with Professor Paolo Samorì.
The research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fonds de Recherche du Québec – Nature et Technologies (FRQNT).
Stoeckel, M.-A., et al. (2021) Analysis of External and Internal Disorder to Understand Band‐Like Transport in n‐Type Organic Semiconductors. Advanced Materials. doi.org/10.1002/adma.202007870.