The hybrid metal halide [(CH)NOH]CoCl exhibits a first-order phase transition at ∼ 343 K. Its crystal structure and caloric properties respond significantly to moderate pressures (1-1000 bar), demonstrating potential for applications in emerging solid-state refrigeration technologies.
View Article and Find Full Text PDFToday, ≈20% of the electric consumption is devoted to refrigeration; while, ≈50% of the final energy is dedicated to heating applications. In this scenario, many cooling devices and heat-pumps are transitioning toward the use of CO as an eco-friendly refrigerant, favoring carbon circular economy. Nevertheless, CO still has some limitations, such as large operating pressures (70-150 bar) and a critical point at 31 °C, which compromises efficiency and increases technological complexity.
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June 2022
A detailed study of lead halide-layered perovskites with general formula APbX (where A is cyclohexylammonium (CHA) or cyclopentylammonium (CPA) cation and X is Cl or Br anion) is presented. Using variable temperature synchrotron X-ray powder diffraction, we observe that these compounds exhibit diverse crystal structures above room temperature. Very interestingly, we report some unconventional thermomechanical responses such as uniaxial negative thermal expansion and colossal positive thermal expansion in a perpendicular direction.
View Article and Find Full Text PDFIn this work, "breathing-caloric" effect is introduced as a new term to define very large thermal changes that arise from the combination of structural changes and gas adsorption processes occurring during breathing transitions. In regard to cooling and heating applications, this innovative caloric effect appears under very low working pressures and in a wide operating temperature range. This phenomenon, whose origin is analyzed in depth, is observed and reported here for the first time in the porous hybrid organic-inorganic MIL-53(Al) material.
View Article and Find Full Text PDFIn this work, we design, build, and test one of the very first barocaloric devices. The here presented device can recover the energy generated by an individual's footstep and transform it into barocaloric heating and/or cooling. Accordingly, we present an innovative device that can provide eco-friendly and gas-free heating/cooling.
View Article and Find Full Text PDFWe have prepared two new lead halides with the novel general formula of DMAPbX (DMA = [(CH)NH] and X = Cl or Br) by using an easy route under mild conditions at room temperature. These compounds exhibit an unprecedented crystal structure, are formed by layers of distorted [PbX] octahedra, which share corners and faces, and contain intercalated DMA cations. Very interestingly, they display dielectric transitions, which are related to a partial order-disorder process of the DMA cations between 160 and 260 K.
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