Concomitant Thermochromic and Phase-Change Effect in a Switchable Spin Crossover Material for Efficient PassiveControl of Day and Night Temperature Fluctuations

Abstract

[EN] The increasing environmental protection demand has prompted thedevelopment of passive thermal regulation systems that reduce temperaturefluctuations in buildings. Here, it is demonstrated that the heat generated bythe sun can trigger a spin crossover (SCO) in a molecule-base material,resulting in a concomitant color variation (from pink to white) and a phasetransition. This leads to a cooling effect with respect to other thermochromicmaterials. In addition, when the material is cooled, a dampening of thetemperature decrease is produced. Therefore, these materials can potentiallybe implemented for passive temperature control in buildings. Furthermore,SCO materials are remarkably stable upon cycling and highly versatile, whichallows for the design of compounds with properties tailored for the desiredclimatic conditions and comfortable temperature.