Grant: Research Tools and Instruments

Understanding charge transport in organic semiconductors (OS) is of paramount importance for gaining deeper knowledge of such molecular solids and conceiving new molecular structures that are more suited for electronic devices. Unlike crystalline silicon, the weak noncovalent nature of the intermolecular interactions in OS does not allow to describe electrons and holes in terms of delocalized Bloch waves therefore most of the conventional experimental techniques employed in solid-state physics to investigate charge transport in these materials fail to describe their complex behavior. Currently, only a few experimental techniques could allow to measure phonon (and vibrational) modes in OS but they are not able to probe the interactions of free charges with such phonon modes.******To fill this major gap, we request the purchase of a cryogenic probestation equipped with windows for optical access that will allow to pioneer a novel type of spectroscopy, Charge Accumulation THz spectroscopy (CATS), which for the first time will measure in situ electron-phonon interactions in molecular materials. Ten research groups at INRS-EMT, McGill University, Polytechnique Montréal, and Université de Montréal (4 applicants and 7 other supportive laboratories) will exploit this tool to support the suggested research. Such novel spectroscopic technique (CATS) represents a major advance in physics, materials science and synthetic chemistry as it is a powerful tool to give a clear indication of which materials are more suited for applications in electronics. By correlating the collected spectral features in absence and in presence of charges, respectively, we could make an efficient screening of the suitability of a given organic molecular design (in the case of OS) for electronics. In the short term, CATS could be extended to other materials such as organic-halide perovskites or quantum dots that have strong phononic response in the THz range. In the long term, the generated knowledge could support future adoption of CATS as a laboratory tool to screen materials for electronics.******The excellent track records and complementary expertise of the three applicants will ensure the fast progress and overall success of the proposed program. Furthermore, given the multipurpose and versatile nature of the requested toolkit, its use will allow to train HQP in at least 11 research teams, which would make a total of ca. 50 Ph.D. students, 20 postdoctoral fellows (PDFs), 20 M.Sc. students and will be also open to host summer students. Since CATS is a novel and powerful technique developed at INRS-EMT, it has a huge potential to provide marketable skills for all HQP trained on the equipment. The requested equipment will also open up opportunities for broad collaborations with industries and universities and thus enhance the students' training by exposing them to industrial working environments and by allowing them to interact with key players in Canada and elsewhere.**