Thermal evaluation of polymorphic transitions in layered hybrid organic-inorganic perovskites for energy storage applications

Layered hybrid organic-inorganic perovskites (LHOIPs) have gained specific attention in applications such as optoelectronics. However, from the thermal perspective, these materials present a high potential for thermal energy storage applications in solid-state due to their heat storage capacity during their phase transitions. Here, we evaluate the first-order transition of these materials from the molecular point of view and make a relation with organic size, which is responsible for the ordering-disordering transition. Six LHOIPs have been synthesised, (C₁₂H₂₅N)₂CuCl₄, (C₁₄H₂₉N)₂CuCl₄, (C₁₆H₃₃N)₂CuCl₄, (C₁₂H₂₄N)₂MnCl₄, (C₁₄H₂₉N)₂MnCl₄ and (C₁₆H₃₃N)₂MnCl₄, where the crystal transformation has been evaluated under X-ray diffraction and Raman, and thermal conductivity as well as the thermal expansion have been studied. This work provides a comprehensive evaluation of the disordering phenomenon that is produced during phase transitions.