Hybrid organic-inorganic materials with phase transitions for solid-state cooling and solar thermal energy storage

Resumo

This Ph.D. Thesis is focused on the study of hybrid organic-inorganic materials with phase transitions for solid-state cooling and energy storage applications. Given the importance of substituting the dangerous, toxic and/or polluting compounds employed in such applications, this work is centered in the selection, design and synthesis of materials with organic and inorganic units that can provide high-energetic phase transitions and other functional properties, fundamental for energy systems such as solid-state cooling and energy storage. The chemical structure and functional properties (caloric, electric and magnetic) were studied to analyze the performance of the materials and contemplate innovative options given by the multi-sensitivity to different stimuli (temperature, pressure or electric field). As result of this research, the hybrid perovskite [(CH3)4N]Mn(N3)3 and the hybrid plastic crystals [(CH3)3(CH2Cl)N]FeCl4, [(CH3)3(CH2Cl)N]GaCl4 and [(CH3)3S]FeCl4 are reported as promising barocaloric materials for solid-state cooling. Furthermore, [(CH3)3(CH2Cl)N]GaCl4 and [(CH3)3S]FeCl4, which are new materials reported in this thesis, revealed very interesting caloric, electric and magnetic properties suitable for solar thermal energy storage applications and the possibility of combining them with electrical energy storage for multi-functional systems. The results here presented are an input to the development of sustainable and environmentally-friendly systems for the use and storage of energy.