Soutenance de thèse de Madame Agnieszka MARJANOWSKA

Le 29 juin 2026 de 12:00 à 15:00

12:00 June 29, 2026 | Institute of Physics | Nicolaus Copernicus University in Toruń | POLOGNE

Sujet : Photovoltaic and nonlinear optical effects of thin films based on perovskites

Directeur de thèse : Monsieur Bouchta SAHRAOUI

RÉSUMÉ

This dissertation studies selected thin film hybrid perovskites with the MABX3 structure, whereB = Pb, Cd, Ge, Sn, Zn, and X = I, Cl, Br. The materials were synthesized by physical vapor co-deposition (PVco-D) and then characterized using a variety of techniques, including atomic force microscopy (AFM), UV-VIS-NIR spectrophotometry, photoluminescence (PL) spectroscopy, second- and third-harmonic generation (SHG, THG), Z-scan, and electrical and photovoltaic measurements. These studies provided detailed information on the effect of chemical composition and composition percentage on the surface topography, structural stability, linear and nonlinear optical properties, and electrical parameters of perovskite solar cells. The studies demonstrated that the stability of perovskites strongly depends on their chemical composition, with materials containing I and Br atoms proving to be the most stable. Spectroscopic measurements over a wide temperature range confirmed the occurrence of phase transitions –from orthorhombic to tetragonal and from tetragonal to cubic. The strongest second-order nonlinear properties were observed for the perovskite containing the Br halogen. Third-order nonlinear effects were observed for all tested materials. Thin film photovoltaic cells with perovskites containing I, Cl, and Br halogens responded to illumination by generating an electrical voltage and achieving efficiencies of 3.43%, 2.80%, and 3.55%, respectively.

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