Seo Jinyoung, McGillicuddy Ryan D, Slavney Adam H, Zhang Selena, Ukani Rahil, Yakovenko Andrey A, Zheng Shao-Liang, Mason Jarad A
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.
X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA.
Nat Commun. 2022 May 9;13(1):2536. doi: 10.1038/s41467-022-29800-9.
Pressure-induced thermal changes in solids-barocaloric effects-can be used to drive cooling cycles that offer a promising alternative to traditional vapor-compression technologies. Efficient barocaloric cooling requires materials that undergo reversible phase transitions with large entropy changes, high sensitivity to hydrostatic pressure, and minimal hysteresis, the combination of which has been challenging to achieve in existing barocaloric materials. Here, we report a new mechanism for achieving colossal barocaloric effects that leverages the large volume and conformational entropy changes of hydrocarbon order-disorder transitions within the organic bilayers of select two-dimensional metal-halide perovskites. Significantly, we show how the confined nature of these order-disorder phase transitions and the synthetic tunability of layered perovskites can be leveraged to reduce phase transition hysteresis through careful control over the inorganic-organic interface. The combination of ultralow hysteresis and high pressure sensitivity leads to colossal reversible isothermal entropy changes (>200 J kg K) at record-low pressures (<300 bar).
固体中压力诱导的热变化——压热效应——可用于驱动冷却循环，为传统蒸汽压缩技术提供了一种有前景的替代方案。高效的压热冷却需要材料经历具有大熵变、对静水压力高灵敏度且滞后极小的可逆相变，而在现有的压热材料中实现这些特性的组合一直具有挑战性。在此，我们报告了一种实现巨大压热效应的新机制，该机制利用了特定二维金属卤化物钙钛矿有机双层内烃类有序-无序转变的大体积和构象熵变。重要的是，我们展示了如何通过仔细控制无机-有机界面，利用这些有序-无序相变的受限性质和层状钙钛矿的合成可调性来减少相变滞后。超低滞后和高压灵敏度的结合在创纪录的低压（<300巴）下导致巨大的可逆等温熵变（>200 J kg⁻¹ K⁻¹）。
