« Hybrid Perovskite Materials: Characterization of their Electrical Properties and Stability at the Nanoscale »par Monsieur Jaume LLACER MARTINEZ

Quand ?
Le 14 décembre 2020 De 14:30 à 17:00
Où ?
Online

Organisé par

Claudia Casa

La défense publique de la thèse de Monsieur Jaume LLACER MARTINEZ aura lieu le 14 décembre 2020 à 14h30par vidéo-conférence, le lien actif sera publié la veille sur ce site.

Promoteur de thèse: Monsieur Philippe LECLERE et Monsieur Didier THERON (co-promoteur)

Résumé

Global warming is one of the main concerns in our society nowadays, year after year the impact and consequences are becoming more visible. The Paris agreement set a target to limit the CO2 emission, which is mainly caused from the increasing demand for energy based on fossil fuels. Since then, the scientific community has increased their efforts on looking for clean energy sources such as renewable energies. In this regard, solar energy is meant to be one of the main energy sources that could replace fossil fuels. Therefore, photovoltaic technologies have evolved tremendously and, organic-inorganic hybrid halide perovskite materials have been one of the technologies with the fastest growth in solar cell performance. Perovskite materials possess unique properties such as flexibility, low-cost and ease to manufacture. Nonetheless, there are still some issues regarding their stability against atmospheric conditions that need to be understood. This dissertation focuses on the characterization of the electrical properties at the nanoscale of perovskite-based thin films by means of scanning probe microscopies (Conducting AFM, Kelvin Probe Force Microscopy, and Scanning Microwave Microscopy). In this growing field of research, many perovskite structures, deposition methods, and synthesis routes have been developed and introduced in perovskite-based solar cells. In the first part of this dissertation, the context of perovskite materials is detailed, and the methodology used through the thesis is also described. Then, we study and compare the electronic properties at the surface of perovskite materials synthesized following two different routes. Moreover, device engineering has been also proven to increase both, the performance, and the stability of perovskite solar cells. In a second part of the thesis, we show that for a given perovskite structure, the stability upon exposure to controlled small amounts of water can be significantly improved through the synthesis optimization. Finally, we provide a series of conclusions and perspectives that could help to further understand the perovskite behaviour at the local scale and to improve the cell performances.