Submitted Abstract
The aim of this Inter-Mobility project is to invite Brahim Dkhil from CentraleSupélec, Université Paris-Saclay (France) to the newly established research group of Jens Kreisel at the University of Luxembourg. The scientific project is entitled “Coupling photo-pyro-piezo-effects in ferroelectrics” (Coφπ2), allowing Brahim Dkhil to stay in Luxembourg for a total of 12 months, distributed over three years. Collaboration context. B. Dkhil (BD) and J. Kreisel (JK) have a long-standing and fruitful research collaboration in ferroelectric materials, a field in which both have an international recognition. During the years 2015 to 2019, BD has already spent considerable time in Luxembourg, visiting JK’s PEARL group, which was then situated at the Luxembourg Institute of Science and Technology (LIST), the stays were financed first through JK’s PEARL, then through an InterMobility-Grant with E. Defay, also member of the PEARL group. These visits have given rise to a total of 9 common publications, plus a book chapter. Double-motivation for this Inter-Mobility application. JK has changed in September 2018 to the University of Luxembourg, where he now sets-up a new research group in the field of Multifunctional Ferroic Materials. As a first motivation, this Mobility-in will provide leverage in the start-up phase of JK’s new group. The second motivation stems from a recent Brainstorming Workshop, which JK has organised to identify future promising research avenues on functional oxides, gathering the PEARL group, three invited profs (among which BD) and colleagues from the University of Luxembourg. Beyond all original ideas, it brought‐up two topics of main consensus 1) Light‐matter interaction in ferroic oxides and 2) Conversion of one energy into another. Motivated by this, we centre the present Inter-Mobility application on photo-effects in pyroelectric and piezoelectric oxide. Scientific context. The present project Coφπ2 stands in the larger context of materials for energy, with the approach to investigate the effect of light on functional oxides. Driven by the ever-increasing demand for clean and renewable energy, various devices that harvest energy from light, heat, and mechanical vibration in our surrounding environment have been widely investigated in the past decades. Among possible candidate materials for energy harvesting, ferroelectrics are very appealing as they show good pyroelectric (conversion of heat into electrical charges), excellent piezoelectric (conversion of mechanical deformations into electrical charges) and, more recently, efficient photovoltaic (conversion of light into electrical charges) properties. However most often each effect is exploited on its own, with little regard to coupling effects. Objective. The main research objective of this research work is to both better understand and explore the physical coupling mechanisms of light to energy-harvesting properties in ferroelectrics. Such understanding step is crucial for the design of improved materials with higher-efficiency. For this, we propose to exploit the multifunctional nature of ferroelectrics, especially through the coupling of a light excitation to pyroelectric and/or piezoelectric properties in order to simultaneously scavenge light, heat and/or mechanical energies with higher efficiency. This two- to three-in-one approach takes advantage of the use of a single, easy to fabricate material structure rather than a complex and costly architecture combining different materials in tandem.