Opal-like photonic structuring of perovskite solar cells using a genetic algorithm approach

Light management is an important area of photovoltaic research, but little is known about it in perovskite solar cells. The present work numerically studies the positive effect of structuring the photo-active layer of perovskite material. This structuration consists of a hybrid absorbing layer made of an uniform part and an opal-like part. A genetic algorithm approach allows us to determine the optimal combination among more than 1.4 10 potential combinations. The optimal combination provides an internal quantum efficiency of 98.1%, nearly 2% higher than for an equivalent unstructured photo-active layer. The robustness of the optimum against potential experimental deviations, as well as the angular dependency of the proposed structure, are examined in the present study.ELSSOL; ARC - Actions de Recherche Concerté

Electrochemical Investigation of Nitinol/Tantalum Hybrid Surfaces Modified by Alkylphosphonic Self-Assembled Monolayers

The surface characteristics of bare and modified nickel-titanium samples (NiTi) are investigated by spectroscopic, microscopic and electrochemical techniques. The successful electrodeposition of a tantalum coating on NiTi and the effective grafting of 1-dodecylphosphonic acid SAMs on both pristine and Ta-covered NiTi surfaces are evidenced and quantified by XPS and SEM. Cyclic voltammetry performed on the different NiTi-based electrodes highlights their specificities regarding electron transfer to a redox probe present in solution (here ruthenium(III) hexamine). Finally, the samples electrochemical characteristics at a local scale are investigated by scanning electrochemical microscopy (SECM). The impact of the surface modifications on mass transport of the redox probe is analyzed through approach curves in the feedback mode, while the recording of current maps in feedback as well as in substrate-generation/tip-collection modes leads to the qualitative identification of electrochemically-active areas corresponding to precursor pitting corrosion sites

Electrochromic Nanomaterials Based on Hybrid Molybdenum-Tungsten Oxide: Synthesis, Wet Coating and Structural / Optoelectronic Characterizations

Hybrid Molybdenum-Tungsten oxides nanomaterials are obtained by solvothermal synthesis. In comparaison with undoped WO3-x, a boost in the optical signature has been observed, which can be linked to a concentration increase of reduced species and oxygen vacancies in the material. The « MoWOx » powder is then wet-processed as thin film by spin coating and succesfully used as plasmonic EC material, dispalying a selective and independent modulation of both visible and NIR wavelengths as a function of the applied potential.PLASMON_E